type) {
return new Builder<>(name, type);
}
/**
* A fluent builder for the {@code Attribute} instances.
*
* All methods could be called only once per builder. The attribute
* already undocumented based on its name cannot be marked as undocumented.
*/
public static class Builder {
private final String name;
private final Type type;
private ConfigurationTransition configTransition = NoTransition.INSTANCE;
private RuleClassNamePredicate allowedRuleClassesForLabels = ANY_RULE;
private RuleClassNamePredicate allowedRuleClassesForLabelsWarning = NO_RULE;
private SplitTransitionProvider splitTransitionProvider;
private FileTypeSet allowedFileTypesForLabels;
private ValidityPredicate validityPredicate = ANY_EDGE;
private Object value;
private AttributeValueSource valueSource = AttributeValueSource.DIRECT;
private boolean valueSet;
private Predicate condition;
private Set propertyFlags = EnumSet.noneOf(PropertyFlag.class);
private PredicateWithMessage allowedValues = null;
private RequiredProviders.Builder requiredProvidersBuilder =
RequiredProviders.acceptAnyBuilder();
private HashMap> aspects = new LinkedHashMap<>();
/**
* Creates an attribute builder with given name and type. This attribute is optional, uses
* target configuration and has a default value the same as its type default value. This
* attribute will be marked as undocumented if its name starts with the dollar sign ({@code $})
* or colon ({@code :}).
*
* @param name attribute name
* @param type attribute type
*/
public Builder(String name, Type type) {
this.name = Preconditions.checkNotNull(name);
this.type = Preconditions.checkNotNull(type);
if (isImplicit(name) || isLateBound(name)) {
setPropertyFlag(PropertyFlag.UNDOCUMENTED, "undocumented");
}
}
private Builder setPropertyFlag(PropertyFlag flag, String propertyName) {
Preconditions.checkState(
!propertyFlags.contains(flag), "%s flag is already set", propertyName);
propertyFlags.add(flag);
return this;
}
/**
* Sets the property flag of the corresponding name if exists, otherwise throws an Exception.
* Only meant to use from Skylark, do not use from Java.
*/
public Builder setPropertyFlag(String propertyName) {
PropertyFlag flag = null;
try {
flag = PropertyFlag.valueOf(propertyName);
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException("unknown attribute flag " + propertyName);
}
setPropertyFlag(flag, propertyName);
return this;
}
/**
* Makes the built attribute mandatory.
*/
public Builder mandatory() {
return setPropertyFlag(PropertyFlag.MANDATORY, "mandatory");
}
/**
* Makes the built attribute non empty, meaning the attribute cannot have an empty list value.
* Only applicable for list type attributes.
*/
public Builder nonEmpty() {
Preconditions.checkNotNull(type.getListElementType(), "attribute '%s' must be a list", name);
return setPropertyFlag(PropertyFlag.NON_EMPTY, "non_empty");
}
/**
* Makes the built attribute producing a single artifact.
*/
public Builder singleArtifact() {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"attribute '%s' must be a label-valued type", name);
return setPropertyFlag(PropertyFlag.SINGLE_ARTIFACT, "single_artifact");
}
/**
* Forces silent ruleclass filtering on the label type attribute.
* This flag is introduced to handle plugins, do not use it in other cases.
*/
public Builder silentRuleClassFilter() {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
return setPropertyFlag(PropertyFlag.SILENT_RULECLASS_FILTER, "silent_ruleclass_filter");
}
/**
* Skip analysis time filetype check. Don't use it if avoidable.
*/
public Builder skipAnalysisTimeFileTypeCheck() {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
return setPropertyFlag(PropertyFlag.SKIP_ANALYSIS_TIME_FILETYPE_CHECK,
"skip_analysis_time_filetype_check");
}
/**
* Mark the built attribute as order-independent.
*/
public Builder orderIndependent() {
Preconditions.checkNotNull(type.getListElementType(), "attribute '%s' must be a list", name);
return setPropertyFlag(PropertyFlag.ORDER_INDEPENDENT, "order-independent");
}
/**
* Mark the built attribute as to use output_licenses for license checking.
*/
public Builder useOutputLicenses() {
Preconditions.checkState(BuildType.isLabelType(type), "must be a label type");
return setPropertyFlag(PropertyFlag.OUTPUT_LICENSES, "output_license");
}
/**
* Defines the configuration transition for this attribute.
*/
public Builder cfg(SplitTransitionProvider splitTransitionProvider) {
Preconditions.checkState(this.configTransition == NoTransition.INSTANCE,
"the configuration transition is already set");
this.splitTransitionProvider = Preconditions.checkNotNull(splitTransitionProvider);
return this;
}
/**
* Defines the configuration transition for this attribute. Defaults to
* {@code NONE}.
*/
public Builder cfg(SplitTransition configTransition) {
return cfg(new BasicSplitTransitionProvider(Preconditions.checkNotNull(configTransition)));
}
/**
* Defines the configuration transition for this attribute. Defaults to
* {@code NONE}.
*/
public Builder cfg(ConfigurationTransition configTransition) {
Preconditions.checkState(this.configTransition == NoTransition.INSTANCE,
"the configuration transition is already set");
if (configTransition instanceof SplitTransition) {
return cfg((SplitTransition) configTransition);
} else {
this.configTransition = configTransition;
return this;
}
}
/**
* Requires the attribute target to be executable; only for label or label
* list attributes. Defaults to {@code false}.
*/
public Builder exec() {
return setPropertyFlag(PropertyFlag.EXECUTABLE, "executable");
}
/**
* Indicates that the attribute (like srcs or hdrs) should be used as an input when calculating
* compile_one_dependency.
*/
public Builder direct_compile_time_input() {
return setPropertyFlag(PropertyFlag.DIRECT_COMPILE_TIME_INPUT,
"direct_compile_time_input");
}
/**
* Makes the built attribute undocumented.
*
* @param reason explanation why the attribute is undocumented. This is not
* used but required for documentation
*/
public Builder undocumented(String reason) {
return setPropertyFlag(PropertyFlag.UNDOCUMENTED, "undocumented");
}
/**
* Sets the attribute default value. The type of the default value must
* match the type parameter. (e.g. list=[], integer=0, string="",
* label=null). The {@code defaultValue} must be immutable.
*
* If defaultValue is of type Label and is a target, that target will
* become an implicit dependency of the Rule; we will load the target
* (and its dependencies) if it encounters the Rule and build the target
* if needs to apply the Rule.
*/
public Builder value(TYPE defaultValue) {
Preconditions.checkState(!valueSet, "the default value is already set");
value = defaultValue;
valueSet = true;
return this;
}
/**
* See value(TYPE) above. This method is only meant for Skylark usage.
*
* The parameter {@code context} is relevant iff the default value is a Label string. In this
* case, {@code context} must point to the parent Label in order to be able to convert the
* default value string to a proper Label.
*
* @param parameterName The name of the attribute to use in error messages
*/
public Builder defaultValue(
Object defaultValue, Object context, @Nullable String parameterName)
throws ConversionException {
Preconditions.checkState(!valueSet, "the default value is already set");
value =
type.convert(
defaultValue,
((parameterName == null) ? "" : String.format("parameter '%s' of ", parameterName))
+ String.format("attribute '%s'", name),
context);
valueSet = true;
return this;
}
/** See value(TYPE) above. This method is only meant for Skylark usage. */
public Builder defaultValue(Object defaultValue) throws ConversionException {
return defaultValue(defaultValue, null, null);
}
public boolean isValueSet() {
return valueSet;
}
/**
* Sets the attribute default value to a computed default value - use this when the default
* value is a function of other attributes of the Rule. The type of the computed default value
* for a mandatory attribute must match the type parameter: (e.g. list=[], integer=0, string="",
* label=null). The {@code defaultValue} implementation must be immutable.
*
* If the computed default returns a Label that is a target, that target will become an
* implicit dependency of this Rule; we will load the target (and its dependencies) if it
* encounters the Rule and build the target if needs to apply the Rule.
*/
public Builder value(ComputedDefault defaultValue) {
Preconditions.checkState(!valueSet, "the default value is already set");
value = defaultValue;
valueSource = AttributeValueSource.COMPUTED_DEFAULT;
valueSet = true;
return this;
}
/**
* Sets the attribute default value to a Skylark computed default template. Like a native
* Computed Default, this allows a Skylark-defined Rule Class to specify that the default value
* of an attribute is a function of other attributes of the Rule.
*
* During the loading phase, the computed default template will be specialized for each rule
* it applies to. Those rules' attribute values will not be references to {@link
* SkylarkComputedDefaultTemplate}s, but instead will be references to {@link
* SkylarkComputedDefault}s.
*
*
If the computed default returns a Label that is a target, that target will become an
* implicit dependency of this Rule; we will load the target (and its dependencies) if it
* encounters the Rule and build the target if needs to apply the Rule.
*/
public Builder value(SkylarkComputedDefaultTemplate skylarkComputedDefaultTemplate) {
Preconditions.checkState(!valueSet, "the default value is already set");
value = skylarkComputedDefaultTemplate;
valueSource = AttributeValueSource.COMPUTED_DEFAULT;
valueSet = true;
return this;
}
/**
* Sets the attribute default value to be late-bound, i.e., it is derived from the build
* configuration and/or the rule's configured attributes.
*/
public Builder value(LateBoundDefault defaultValue) {
Preconditions.checkState(!valueSet, "the default value is already set");
value = defaultValue;
valueSource = AttributeValueSource.LATE_BOUND;
valueSet = true;
return this;
}
/**
* Returns where the value of this attribute comes from. Useful only for Skylark.
*/
public AttributeValueSource getValueSource() {
return valueSource;
}
/**
* Sets a condition predicate. The default value of the attribute only applies if the condition
* evaluates to true. If the value is explicitly provided, then this condition is ignored.
*
* The condition is only evaluated if the attribute is not explicitly set, and after all
* explicit attributes have been set. It can generally not access default values of other
* attributes.
*/
public Builder condition(Predicate condition) {
Preconditions.checkState(this.condition == null, "the condition is already set");
this.condition = condition;
return this;
}
/**
* Switches on the capability of an attribute to be published to the rule's
* tag set.
*/
public Builder taggable() {
return setPropertyFlag(PropertyFlag.TAGGABLE, "taggable");
}
/**
* Disables dependency checks done by
* {@link com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider.PrerequisiteValidator}.
*/
public Builder skipPrereqValidatorCheck() {
return setPropertyFlag(PropertyFlag.SKIP_PREREQ_VALIDATOR_CHECKS,
"skip_prereq_validator_checks");
}
/**
* Enforces constraint checking on this attribute even if default enforcement policy would skip
* it. If default policy checks the attribute, this is a no-op.
*
* Most attributes are enforced by default, so in the common case this call is unnecessary.
*
*
See {@link com.google.devtools.build.lib.analysis.constraints.ConstraintSemantics#getConstraintCheckedDependencies}
* for enforcement policy details.
*/
public Builder checkConstraints() {
Verify.verify(!propertyFlags.contains(PropertyFlag.SKIP_CONSTRAINTS_OVERRIDE),
"constraint checking is already overridden to be skipped");
return setPropertyFlag(PropertyFlag.CHECK_CONSTRAINTS_OVERRIDE, "check_constraints");
}
/**
* Skips constraint checking on this attribute even if default enforcement policy would check
* it. If default policy skips the attribute, this is a no-op.
*
* See {@link com.google.devtools.build.lib.analysis.constraints.ConstraintSemantics#getConstraintCheckedDependencies}
* for enforcement policy details.
*/
public Builder dontCheckConstraints() {
Verify.verify(!propertyFlags.contains(PropertyFlag.CHECK_CONSTRAINTS_OVERRIDE),
"constraint checking is already overridden to be checked");
return setPropertyFlag(PropertyFlag.SKIP_CONSTRAINTS_OVERRIDE, "dont_check_constraints");
}
/**
* If this is a label or label-list attribute, then this sets the allowed rule types for the
* labels occurring in the attribute.
*
* If the attribute contains Labels of any other rule type, then if they're in
* {@link #allowedRuleClassesForLabelsWarning}, the build continues with a warning. Else if
* they fulfill {@link #getMandatoryNativeProvidersList()}, the build continues without error.
* Else the build fails during analysis.
*
*
If neither this nor {@link #allowedRuleClassesForLabelsWarning} is set, only rules that
* fulfill {@link #getMandatoryNativeProvidersList()} build without error.
*
*
This only works on a per-target basis, not on a per-file basis; with other words, it
* works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedRuleClasses(Iterable allowedRuleClasses) {
return allowedRuleClasses(
RuleClassNamePredicate.only(allowedRuleClasses));
}
/**
* If this is a label or label-list attribute, then this sets the allowed rule types for the
* labels occurring in the attribute.
*
* If the attribute contains Labels of any other rule type, then if they're in
* {@link #allowedRuleClassesForLabelsWarning}, the build continues with a warning. Else if
* they fulfill {@link #getMandatoryNativeProvidersList()}, the build continues without error.
* Else the build fails during analysis.
*
*
If neither this nor {@link #allowedRuleClassesForLabelsWarning} is set, only rules that
* fulfill {@link #getMandatoryNativeProvidersList()} build without error.
*
*
This only works on a per-target basis, not on a per-file basis; with other words, it
* works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedRuleClasses(RuleClassNamePredicate allowedRuleClasses) {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
propertyFlags.add(PropertyFlag.STRICT_LABEL_CHECKING);
allowedRuleClassesForLabels = allowedRuleClasses;
return this;
}
/**
* If this is a label or label-list attribute, then this sets the allowed rule types for the
* labels occurring in the attribute.
*
* If the attribute contains Labels of any other rule type, then if they're in
* {@link #allowedRuleClassesForLabelsWarning}, the build continues with a warning. Else if
* they fulfill {@link #getMandatoryNativeProvidersList()}, the build continues without error.
* Else the build fails during analysis.
*
*
If neither this nor {@link #allowedRuleClassesForLabelsWarning} is set, only rules that
* fulfill {@link #getMandatoryNativeProvidersList()} build without error.
*
*
This only works on a per-target basis, not on a per-file basis; with other words, it
* works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedRuleClasses(String... allowedRuleClasses) {
return allowedRuleClasses(ImmutableSet.copyOf(allowedRuleClasses));
}
/**
* If this is a label or label-list attribute, then this sets the allowed
* file types for file labels occurring in the attribute. If the attribute
* contains labels that correspond to files of any other type, then an error
* is produced during the analysis phase.
*
* This only works on a per-target basis, not on a per-file basis; with
* other words, it works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedFileTypes(FileTypeSet allowedFileTypes) {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
propertyFlags.add(PropertyFlag.STRICT_LABEL_CHECKING);
allowedFileTypesForLabels = Preconditions.checkNotNull(allowedFileTypes);
return this;
}
/**
* Allow all files for legacy compatibility. All uses of this method should be audited and then
* removed. In some cases, it's correct to allow any file, but mostly the set of files should be
* restricted to a reasonable set.
*/
public Builder legacyAllowAnyFileType() {
return allowedFileTypes(FileTypeSet.ANY_FILE);
}
/**
* If this is a label or label-list attribute, then this sets the allowed
* file types for file labels occurring in the attribute. If the attribute
* contains labels that correspond to files of any other type, then an error
* is produced during the analysis phase.
*
* This only works on a per-target basis, not on a per-file basis; with
* other words, it works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedFileTypes(FileType... allowedFileTypes) {
return allowedFileTypes(FileTypeSet.of(allowedFileTypes));
}
/**
* If this is a label or label-list attribute, then this sets the allowed rule types with
* warning for the labels occurring in the attribute. This must be a disjoint set from
* {@link #allowedRuleClasses}.
*
* If the attribute contains Labels of any other rule type (other than this or those set in
* allowedRuleClasses()) and they fulfill {@link #getMandatoryNativeProvidersList()}}, the build
* continues without error. Else the build fails during analysis.
*
*
If neither this nor {@link #allowedRuleClassesForLabels} is set, only rules that
* fulfill {@link #getMandatoryNativeProvidersList()} build without error.
*
*
This only works on a per-target basis, not on a per-file basis; with other words, it
* works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedRuleClassesWithWarning(Collection allowedRuleClasses) {
return allowedRuleClassesWithWarning(
RuleClassNamePredicate.only(allowedRuleClasses));
}
/**
* If this is a label or label-list attribute, then this sets the allowed rule types with
* warning for the labels occurring in the attribute. This must be a disjoint set from
* {@link #allowedRuleClasses}.
*
* If the attribute contains Labels of any other rule type (other than this or those set in
* allowedRuleClasses()) and they fulfill {@link #getMandatoryNativeProvidersList()}}, the build
* continues without error. Else the build fails during analysis.
*
*
If neither this nor {@link #allowedRuleClassesForLabels} is set, only rules that
* fulfill {@link #getMandatoryNativeProvidersList()} build without error.
*
*
This only works on a per-target basis, not on a per-file basis; with other words, it
* works for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedRuleClassesWithWarning(RuleClassNamePredicate allowedRuleClasses) {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
propertyFlags.add(PropertyFlag.STRICT_LABEL_CHECKING);
allowedRuleClassesForLabelsWarning = allowedRuleClasses;
return this;
}
/**
* If this is a label or label-list attribute, then this sets the allowed rule types with
* warning for the labels occurring in the attribute. This must be a disjoint set from {@link
* #allowedRuleClasses}.
*
* If the attribute contains Labels of any other rule type (other than this or those set in
* allowedRuleClasses()) and they fulfill {@link #getRequiredProviders()}}, the build continues
* without error. Else the build fails during analysis.
*
*
If neither this nor {@link #allowedRuleClassesForLabels} is set, only rules that fulfill
* {@link #getRequiredProviders()} build without error.
*
*
This only works on a per-target basis, not on a per-file basis; with other words, it works
* for 'deps' attributes, but not 'srcs' attributes.
*/
public Builder allowedRuleClassesWithWarning(String... allowedRuleClasses) {
return allowedRuleClassesWithWarning(ImmutableSet.copyOf(allowedRuleClasses));
}
/**
* Sets a list of lists of mandatory native providers. Every configured target occurring in this
* label type attribute has to provide all the providers from one of those lists, otherwise an
* error is produced during the analysis phase.
*/
public final Builder mandatoryNativeProvidersList(
Iterable>> providersList) {
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
for (Iterable> providers : providersList) {
this.requiredProvidersBuilder.addNativeSet(ImmutableSet.copyOf(providers));
}
return this;
}
public Builder mandatoryNativeProviders(
Iterable> providers) {
if (providers.iterator().hasNext()) {
mandatoryNativeProvidersList(ImmutableList.of(providers));
}
return this;
}
/**
* Sets a list of sets of mandatory Skylark providers. Every configured target occurring in
* this label type attribute has to provide all the providers from one of those sets,
* or be one of {@link #allowedRuleClasses}, otherwise an error is produced during
* the analysis phase.
*/
public Builder mandatoryProvidersList(
Iterable> providersList){
Preconditions.checkState(type.getLabelClass() == LabelClass.DEPENDENCY,
"must be a label-valued type");
for (Iterable providers : providersList) {
this.requiredProvidersBuilder.addSkylarkSet(ImmutableSet.copyOf(providers));
}
return this;
}
public Builder legacyMandatoryProviders(String... ids) {
return mandatoryProviders(
Iterables.transform(
Arrays.asList(ids),
s -> {
Preconditions.checkNotNull(s);
return SkylarkProviderIdentifier.forLegacy(s);
}));
}
public Builder mandatoryProviders(Iterable providers) {
if (providers.iterator().hasNext()) {
mandatoryProvidersList(ImmutableList.of(providers));
}
return this;
}
public Builder mandatoryProviders(SkylarkProviderIdentifier... providers) {
mandatoryProviders(Arrays.asList(providers));
return this;
}
/**
* Asserts that a particular parameterized aspect probably needs to be computed for all direct
* dependencies through this attribute.
*
* @param evaluator function that extracts aspect parameters from rule. If it returns null,
* then the aspect will not be attached.
*/
public Builder aspect(
NativeAspectClass aspect, Function evaluator) {
NativeRuleAspect nativeRuleAspect = new NativeRuleAspect(aspect, evaluator);
RuleAspect oldAspect = this.aspects.put(nativeRuleAspect.getName(), nativeRuleAspect);
if (oldAspect != null) {
throw new AssertionError(
String.format("Aspect %s has already been added", oldAspect.getName()));
}
return this;
}
/**
* Asserts that a particular parameterized aspect probably needs to be computed for all direct
* dependencies through this attribute.
*/
public Builder aspect(NativeAspectClass aspect) {
return this.aspect(aspect, input -> AspectParameters.EMPTY);
}
public Builder aspect(SkylarkDefinedAspect skylarkAspect, Location location)
throws EvalException {
SkylarkRuleAspect skylarkRuleAspect = new SkylarkRuleAspect(skylarkAspect);
RuleAspect oldAspect = this.aspects.put(skylarkAspect.getName(), skylarkRuleAspect);
if (oldAspect != null) {
throw new EvalException(
location, String.format("aspect %s added more than once", skylarkAspect.getName()));
}
return this;
}
/**
* Should only be used for deserialization.
*/
public Builder aspect(final Aspect aspect) {
PredefinedRuleAspect predefinedRuleAspect = new PredefinedRuleAspect(aspect);
RuleAspect oldAspect =
this.aspects.put(predefinedRuleAspect.getName(), predefinedRuleAspect);
if (oldAspect != null) {
throw new AssertionError(
String.format("Aspect %s has already been added", oldAspect.getName()));
}
return this;
}
/**
* Sets the predicate-like edge validity checker.
*/
public Builder validityPredicate(ValidityPredicate validityPredicate) {
propertyFlags.add(PropertyFlag.STRICT_LABEL_CHECKING);
this.validityPredicate = validityPredicate;
return this;
}
/**
* The value of the attribute must be one of allowedValues.
*/
public Builder allowedValues(PredicateWithMessage allowedValues) {
this.allowedValues = allowedValues;
propertyFlags.add(PropertyFlag.CHECK_ALLOWED_VALUES);
return this;
}
/**
* Makes the built attribute "non-configurable", i.e. its value cannot be influenced by
* the build configuration. Attributes are "configurable" unless explicitly opted out here.
*
* Non-configurability indicates an exceptional state: there exists Blaze logic that needs
* the attribute's value, has no access to configurations, and can't apply a workaround
* through an appropriate {@link AbstractAttributeMapper} implementation. Scenarios like
* this should be as uncommon as possible, so it's important we maintain clear documentation
* on what causes them and why users consequently can't configure certain attributes.
*
* @param reason why this attribute can't be configurable. This isn't used by Blaze - it's
* solely a documentation mechanism.
*/
public Builder nonconfigurable(String reason) {
Preconditions.checkState(!reason.isEmpty());
return setPropertyFlag(PropertyFlag.NONCONFIGURABLE, "nonconfigurable");
}
/**
* Creates the attribute. Uses name, type, optionality, configuration type
* and the default value configured by the builder.
*/
public Attribute build() {
return build(this.name);
}
/**
* Creates the attribute. Uses type, optionality, configuration type
* and the default value configured by the builder. Use the name
* passed as an argument. This function is used by Skylark where the
* name is provided only when we build. We don't want to modify the
* builder, as it is shared in a multithreaded environment.
*/
public Attribute build(String name) {
Preconditions.checkState(!name.isEmpty(), "name has not been set");
if (valueSource == AttributeValueSource.LATE_BOUND) {
Preconditions.checkState(isLateBound(name));
}
// TODO(bazel-team): Set the default to be no file type, then remove this check, and also
// remove all allowedFileTypes() calls without parameters.
// do not modify this.allowedFileTypesForLabels, instead create a copy.
FileTypeSet allowedFileTypesForLabels = this.allowedFileTypesForLabels;
if (type.getLabelClass() == LabelClass.DEPENDENCY) {
if (isPrivateAttribute(name) && allowedFileTypesForLabels == null) {
allowedFileTypesForLabels = FileTypeSet.ANY_FILE;
}
Preconditions.checkNotNull(
allowedFileTypesForLabels, "allowedFileTypesForLabels not set for %s", name);
} else if (type.getLabelClass() == LabelClass.OUTPUT) {
// TODO(bazel-team): Set the default to no file type and make explicit calls instead.
if (allowedFileTypesForLabels == null) {
allowedFileTypesForLabels = FileTypeSet.ANY_FILE;
}
}
Preconditions.checkState(
!allowedRuleClassesForLabels.consideredOverlapping(allowedRuleClassesForLabelsWarning),
"allowedRuleClasses %s and allowedRuleClassesWithWarning %s "
+ "may not contain the same rule classes",
allowedRuleClassesForLabels,
allowedRuleClassesForLabelsWarning);
return new Attribute(
name,
type,
Sets.immutableEnumSet(propertyFlags),
valueSet ? value : type.getDefaultValue(),
configTransition,
splitTransitionProvider,
allowedRuleClassesForLabels,
allowedRuleClassesForLabelsWarning,
allowedFileTypesForLabels,
validityPredicate,
condition,
allowedValues,
requiredProvidersBuilder.build(),
ImmutableList.copyOf(aspects.values()));
}
}
/**
* A strategy for dealing with too many computations, used when creating lookup tables for {@link
* ComputedDefault}s.
*
* @param The type of exception this strategy throws if too many computations are
* attempted.
*/
interface ComputationLimiter {
void onComputationCount(int count) throws TException;
}
/**
* An implementation of {@link ComputationLimiter} that never throws. For use with
* natively-defined {@link ComputedDefault}s, which are limited in the number of configurable
* attributes they depend on, not on the number of different combinations of possible inputs.
*/
private static final ComputationLimiter NULL_COMPUTATION_LIMITER =
new ComputationLimiter() {
@Override
public void onComputationCount(int count) throws RuntimeException {}
};
/** Exception for computed default attributes that depend on too many configurable attributes. */
private static class TooManyConfigurableAttributesException extends Exception {
TooManyConfigurableAttributesException(int max) {
super(
String.format(
"Too many configurable attributes to compute all possible values: "
+ "Found more than %d possible values.",
max));
}
}
private static class FixedComputationLimiter
implements ComputationLimiter {
/** Upper bound of the number of combinations of values for a computed default attribute. */
private static final int COMPUTED_DEFAULT_MAX_COMBINATIONS = 64;
private static final FixedComputationLimiter INSTANCE = new FixedComputationLimiter();
@Override
public void onComputationCount(int count) throws TooManyConfigurableAttributesException {
if (count > COMPUTED_DEFAULT_MAX_COMBINATIONS) {
throw new TooManyConfigurableAttributesException(COMPUTED_DEFAULT_MAX_COMBINATIONS);
}
}
}
/**
* Specifies how values of {@link ComputedDefault} attributes are computed based on the values of
* other attributes.
*
* The {@code TComputeException} type parameter allows the two specializations of this class to
* describe whether and how their computations throw. For natively defined computed defaults,
* computation does not throw, but for Skylark-defined computed defaults, computation may throw
* {@link InterruptedException}.
*/
private abstract static class ComputationStrategy {
abstract Object compute(AttributeMap map) throws TComputeException;
/**
* Returns a lookup table mapping from:
*
*
* tuples of values that may be assigned by {@code rule} to attributes with names in {@code
* dependencies} (note that there may be more than one such tuple for any given rule, if any
* of the dependencies are configurable)
*
*
* to:
*
*
* the value {@link #compute(AttributeMap)} evaluates to when the provided {@link
* AttributeMap} contains the values specified by that assignment, or {@code null} if the
* {@link ComputationStrategy} failed to evaluate.
*
*
* The lookup table contains a tuple for each possible assignment to the {@code dependencies}
* attributes. The meaning of each tuple is well-defined because {@code dependencies} is
* ordered.
*
*
This is useful because configurable attributes may have many possible values. During the
* loading phase a configurable attribute can't be resolved to a single value. Configuration
* information, needed to resolve such an attribute, is only available during analysis. However,
* any labels that a ComputedDefault attribute may evaluate to must be loaded during the loading
* phase.
*/
Map, T> computeValuesForAllCombinations(
List dependencies,
Type type,
Rule rule,
ComputationLimiter limiter)
throws TComputeException, TLimitException {
// This will hold every (value1, value2, ..) combination of the declared dependencies.
// Collect those combinations.
AggregatingAttributeMapper mapper = AggregatingAttributeMapper.of(rule);
List> depMaps = mapper.visitAttributes(dependencies, limiter);
// For each combination, call compute() on a specialized AttributeMap providing those
// values.
Map, T> valueMap = new HashMap<>(depMaps.size());
for (Map depMap : depMaps) {
AttributeMap attrMap = mapper.createMapBackedAttributeMap(depMap);
Object value = compute(attrMap);
List key = createDependencyAssignmentTuple(dependencies, attrMap);
valueMap.put(key, type.cast(value));
}
return valueMap;
}
/**
* Given an {@link AttributeMap}, containing an assignment to each attribute in {@code
* dependencies}, this returns a list of the assigned values, ordered as {@code dependencies} is
* ordered.
*/
static List createDependencyAssignmentTuple(
List dependencies, AttributeMap attrMap) {
ArrayList tuple = new ArrayList<>(dependencies.size());
for (String attrName : dependencies) {
Type attrType = attrMap.getAttributeType(attrName);
tuple.add(attrMap.get(attrName, attrType));
}
return tuple;
}
}
/**
* A computed default is a default value for a Rule attribute that is a function of other
* attributes of the rule.
*
* Attributes whose defaults are computed are first initialized to the default for their type,
* and then the computed defaults are evaluated after all non-computed defaults have been
* initialized. There is no defined order among computed defaults, so they must not depend on each
* other.
*
*
If a computed default reads the value of another attribute, at least one of the following
* must be true:
*
*
* The other attribute must be declared in the computed default's constructor
* The other attribute must be non-configurable ({@link Builder#nonconfigurable}
*
*
* The reason for enforced declarations is that, since attribute values might be configurable,
* a computed default that depends on them may itself take multiple values. Since we have no
* access to a target's configuration at the time these values are computed, we need the ability
* to probe the default's *complete* dependency space. Declared dependencies allow us to do so
* sanely. Non-configurable attributes don't have this problem because their value is fixed and
* known even without configuration information.
*
*
Implementations of this interface must be immutable.
*/
public abstract static class ComputedDefault {
private final ImmutableList dependencies;
/**
* Create a computed default that can read all non-configurable attribute values and no
* configurable attribute values.
*/
public ComputedDefault() {
this(ImmutableList.of());
}
/**
* Create a computed default that can read all non-configurable attributes values and one
* explicitly specified configurable attribute value
*/
public ComputedDefault(String depAttribute) {
this(ImmutableList.of(depAttribute));
}
/**
* Create a computed default that can read all non-configurable attributes values and two
* explicitly specified configurable attribute values.
*/
public ComputedDefault(String depAttribute1, String depAttribute2) {
this(ImmutableList.of(depAttribute1, depAttribute2));
}
/**
* Creates a computed default that can read all non-configurable attributes and some explicitly
* specified configurable attribute values.
*
* This constructor should not be used by native {@link ComputedDefault} functions. The limit
* of at-most-two depended-on configurable attributes is intended, to limit the exponential
* growth of possible values. {@link SkylarkComputedDefault} uses this, but is limited by {@link
* FixedComputationLimiter#COMPUTED_DEFAULT_MAX_COMBINATIONS}.
*/
protected ComputedDefault(ImmutableList dependencies) {
// Order is important for #createDependencyAssignmentTuple.
this.dependencies = Ordering.natural().immutableSortedCopy(dependencies);
}
Iterable getPossibleValues(Type type, Rule rule) {
final ComputedDefault owner = ComputedDefault.this;
ComputationStrategy strategy =
new ComputationStrategy() {
@Override
public Object compute(AttributeMap map) {
return owner.getDefault(map);
}
};
// Note that this uses ArrayList instead of something like ImmutableList because some
// values may be null.
return new ArrayList<>(
strategy
.computeValuesForAllCombinations(dependencies, type, rule, NULL_COMPUTATION_LIMITER)
.values());
}
/** The list of configurable attributes this ComputedDefault declares it may read. */
public ImmutableList dependencies() {
return dependencies;
}
/**
* Returns the value this {@link ComputedDefault} evaluates to, given the inputs contained in
* {@code rule}.
*/
public abstract Object getDefault(AttributeMap rule);
}
/**
* A Skylark-defined computed default, which can be precomputed for a specific {@link Rule} by
* calling {@link #computePossibleValues}, which returns a {@link SkylarkComputedDefault} that
* contains a lookup table.
*/
public static final class SkylarkComputedDefaultTemplate {
private final Type type;
private final SkylarkCallbackFunction callback;
private final Location location;
private final ImmutableList dependencies;
/**
* Creates a new SkylarkComputedDefaultTemplate that allows the computation of attribute values
* via a callback function during loading phase.
*
* @param type The type of the value of this attribute.
* @param dependencies A list of all names of other attributes that are accessed by this
* attribute.
* @param callback A function to compute the actual attribute value.
* @param location The location of the Skylark function.
*/
public SkylarkComputedDefaultTemplate(
Type type,
ImmutableList dependencies,
SkylarkCallbackFunction callback,
Location location) {
this.type = Preconditions.checkNotNull(type);
// Order is important for #createDependencyAssignmentTuple.
this.dependencies =
Ordering.natural().immutableSortedCopy(Preconditions.checkNotNull(dependencies));
this.callback = Preconditions.checkNotNull(callback);
this.location = Preconditions.checkNotNull(location);
}
/**
* Returns a {@link SkylarkComputedDefault} containing a lookup table specifying the output of
* this {@link SkylarkComputedDefaultTemplate}'s callback given each possible assignment {@code
* rule} might make to the attributes specified by {@link #dependencies}.
*
* If the rule is missing an attribute specified by {@link #dependencies}, or if there are
* too many possible assignments, or if any evaluation fails, this throws {@link
* CannotPrecomputeDefaultsException}.
*
*
May only be called after all non-{@link ComputedDefault} attributes have been set on the
* {@code rule}.
*/
SkylarkComputedDefault computePossibleValues(
Attribute attr, final Rule rule, final EventHandler eventHandler)
throws InterruptedException, CannotPrecomputeDefaultsException {
final SkylarkComputedDefaultTemplate owner = SkylarkComputedDefaultTemplate.this;
final String msg =
String.format(
"Cannot compute default value of attribute '%s' in rule '%s': ",
attr.getPublicName(), rule.getLabel());
final AtomicReference caughtEvalExceptionIfAny = new AtomicReference<>();
ComputationStrategy strategy =
new ComputationStrategy() {
@Override
public Object compute(AttributeMap map) throws InterruptedException {
try {
return owner.computeValue(eventHandler, map);
} catch (EvalException ex) {
caughtEvalExceptionIfAny.compareAndSet(null, ex);
return null;
}
}
};
ImmutableList.Builder> dependencyTypesBuilder = ImmutableList.builder();
Map, Object> lookupTable = new HashMap<>();
try {
for (String dependency : dependencies) {
Attribute attribute = rule.getRuleClassObject().getAttributeByNameMaybe(dependency);
if (attribute == null) {
throw new AttributeNotFoundException(
String.format("No such attribute %s in rule %s", dependency, rule.getLabel()));
}
dependencyTypesBuilder.add(attribute.getType());
}
lookupTable.putAll(
strategy.computeValuesForAllCombinations(
dependencies, attr.getType(), rule, FixedComputationLimiter.INSTANCE));
if (caughtEvalExceptionIfAny.get() != null) {
throw caughtEvalExceptionIfAny.get();
}
} catch (AttributeNotFoundException
| TooManyConfigurableAttributesException
| EvalException ex) {
String error = msg + ex.getMessage();
rule.reportError(error, eventHandler);
throw new CannotPrecomputeDefaultsException(error);
}
return new SkylarkComputedDefault(dependencies, dependencyTypesBuilder.build(), lookupTable);
}
private Object computeValue(EventHandler eventHandler, AttributeMap rule)
throws EvalException, InterruptedException {
Map attrValues = new HashMap<>();
for (String attrName : rule.getAttributeNames()) {
Attribute attr = rule.getAttributeDefinition(attrName);
if (!attr.hasComputedDefault()) {
Object value = rule.get(attrName, attr.getType());
if (!EvalUtils.isNullOrNone(value)) {
attrValues.put(attr.getName(), value);
}
}
}
return invokeCallback(eventHandler, attrValues);
}
private Object invokeCallback(EventHandler eventHandler, Map attrValues)
throws EvalException, InterruptedException {
ClassObject attrs =
NativeProvider.STRUCT.create(
attrValues, "No such regular (non computed) attribute '%s'.");
Object result = callback.call(eventHandler, attrs);
try {
return type.cast((result == Runtime.NONE) ? type.getDefaultValue() : result);
} catch (ClassCastException ex) {
throw new EvalException(
location,
String.format(
"expected '%s', but got '%s'", type, EvalUtils.getDataTypeName(result, true)));
}
}
private static class AttributeNotFoundException extends Exception {
private AttributeNotFoundException(String message) {
super(message);
}
}
static class CannotPrecomputeDefaultsException extends Exception {
private CannotPrecomputeDefaultsException(String message) {
super(message);
}
}
}
/**
* A class for computed attributes defined in Skylark.
*
* Unlike {@link ComputedDefault}, instances of this class contain a pre-computed table of all
* possible assignments of depended-on attributes and what the Skylark function evaluates to, and
* {@link #getPossibleValues(Type, Rule)} and {@link #getDefault(AttributeMap)} do lookups in that
* table.
*/
static final class SkylarkComputedDefault extends ComputedDefault {
private final List> dependencyTypes;
private final Map, Object> lookupTable;
/**
* Creates a new SkylarkComputedDefault containing a lookup table.
*
* @param requiredAttributes A list of all names of other attributes that are accessed by this
* attribute.
* @param dependencyTypes A list of requiredAttributes' types.
* @param lookupTable An exhaustive mapping from requiredAttributes assignments to values this
* computed default evaluates to.
*/
SkylarkComputedDefault(
ImmutableList requiredAttributes,
ImmutableList> dependencyTypes,
Map, Object> lookupTable) {
super(Preconditions.checkNotNull(requiredAttributes));
this.dependencyTypes = Preconditions.checkNotNull(dependencyTypes);
this.lookupTable = Preconditions.checkNotNull(lookupTable);
}
List> getDependencyTypes() {
return dependencyTypes;
}
Map, Object> getLookupTable() {
return lookupTable;
}
@Override
public Object getDefault(AttributeMap rule) {
List key = ComputationStrategy.createDependencyAssignmentTuple(dependencies(), rule);
Preconditions.checkState(
lookupTable.containsKey(key),
"Error in rule '%s': precomputed value missing for dependencies: %s. Available keys: %s.",
rule.getLabel(),
Iterables.toString(key),
Iterables.toString(lookupTable.keySet()));
return lookupTable.get(key);
}
@Override
Iterable getPossibleValues(Type type, Rule rule) {
List result = new ArrayList<>(lookupTable.size());
for (Object obj : lookupTable.values()) {
result.add(type.cast(obj));
}
return result;
}
}
private static class SimpleLateBoundDefault
extends LateBoundDefault {
private final Resolver resolver;
private SimpleLateBoundDefault(boolean useHostConfiguration,
Class fragmentClass,
ValueT defaultValue, Resolver resolver) {
super(useHostConfiguration, fragmentClass, defaultValue);
this.resolver = resolver;
}
@Override
public ValueT resolve(Rule rule, AttributeMap attributes, FragmentT input) {
return resolver.resolve(rule, attributes, input);
}
}
// TODO(b/65746853): Remove documentation about accepting BuildConfiguration when uses are cleaned
// up.
/**
* Provider of values for late-bound attributes. See {@link Attribute#value(LateBoundDefault value)}.
*
* Use sparingly - having different values for attributes during loading and analysis can
* confuse users.
*
* @param The type of value that is used to compute this value. This is usually a
* subclass of BuildConfiguration.Fragment. It may also be Void to receive null, or
* BuildConfiguration itself to receive the entire configuration.
* @param The type of value returned by this class. Must be either {@link Void}, a {@link
* Label}, or a {@link List} of {@link Label} objects.
*/
@Immutable
public abstract static class LateBoundDefault {
/**
* Functional interface for computing the value of a late-bound attribute.
*
* Implementations of this interface must be immutable.
*/
@FunctionalInterface
public interface Resolver {
ValueT resolve(Rule rule, AttributeMap attributeMap, FragmentT input);
}
private final boolean useHostConfiguration;
private final ValueT defaultValue;
private final Class fragmentClass;
/**
* Creates a new LateBoundDefault which always returns the given value.
*
* This is used primarily for matching names with late-bound attributes on other rules and
* for testing. Use normal default values if the name does not matter.
*/
@VisibleForTesting
public static LabelLateBoundDefault fromConstantForTesting(Label defaultValue) {
return new LabelLateBoundDefault(
false,
Void.class,
Preconditions.checkNotNull(defaultValue),
(rule, attributes, unused) -> defaultValue) {};
}
/**
* Creates a new LateBoundDefault which always returns null.
*
* This is used primarily for matching names with late-bound attributes on other rules and
* for testing. Use normal default values if the name does not matter.
*/
@SuppressWarnings("unchecked") // bivariant implementation
public static LateBoundDefault alwaysNull() {
return (LateBoundDefault) AlwaysNullLateBoundDefault.INSTANCE;
}
protected LateBoundDefault(
boolean useHostConfiguration,
Class fragmentClass,
ValueT defaultValue) {
this.useHostConfiguration = useHostConfiguration;
this.defaultValue = defaultValue;
this.fragmentClass = fragmentClass;
}
/**
* Whether to look up the label in the host configuration. This is only here for host
* compilation tools - we usually need to look up labels in the target configuration.
*/
public final boolean useHostConfiguration() {
return useHostConfiguration;
}
/**
* Returns the input type that the attribute expects. This is almost always a configuration
* fragment to be retrieved from the target's configuration (or the host configuration).
*
* It may also be {@link Void} to receive null. This is rarely necessary, but can be used,
* e.g., if the attribute is named to match an attribute in another rule which is late-bound.
*
*
It may also be BuildConfiguration to receive the entire configuration. This is deprecated,
* and only necessary when the default is computed from methods of BuildConfiguration itself.
*/
public final Class getFragmentClass() {
return fragmentClass;
}
/** The default value for the attribute that is set during the loading phase. */
public final ValueT getDefault() {
return defaultValue;
}
/**
* The actual value for the attribute for the analysis phase, which depends on the build
* configuration. Note that configurations transitions are applied after the late-bound
* attribute was evaluated.
*
* @param rule the rule being evaluated
* @param attributes interface for retrieving the values of the rule's other attributes
* @param input the configuration fragment to evaluate with
*/
public abstract ValueT resolve(Rule rule, AttributeMap attributes, FragmentT input);
}
/**
* An abstract {@link LateBoundDefault} class so that {@code SkylarkLateBoundDefault} can derive
* from {@link LateBoundDefault} without compromising the type-safety of the second generic
* parameter to {@link LateBoundDefault}.
*/
public abstract static class AbstractLabelLateBoundDefault
extends LateBoundDefault {
protected AbstractLabelLateBoundDefault(
boolean useHostConfiguration, Class fragmentClass, Label defaultValue) {
super(useHostConfiguration, fragmentClass, defaultValue);
}
}
private static class AlwaysNullLateBoundDefault extends SimpleLateBoundDefault {
static final AlwaysNullLateBoundDefault INSTANCE = new AlwaysNullLateBoundDefault();
private AlwaysNullLateBoundDefault() {
super(false, Void.class, null, (rule, attributes, unused) -> null);
}
}
/** A {@link LateBoundDefault} for a {@link Label}. */
public static class LabelLateBoundDefault
extends SimpleLateBoundDefault {
private LabelLateBoundDefault(
boolean useHostConfiguration,
Class fragmentClass,
Label defaultValue,
Resolver resolver) {
super(useHostConfiguration, fragmentClass, defaultValue, resolver);
}
/**
* Creates a new LabelLateBoundDefault which uses the rule, its configured attributes, and a
* fragment of the target configuration.
*
* Note that the configuration fragment here does not take into account any transitions that
* are on the attribute with this LabelLateBoundDefault as its value. The configuration will be
* the same as the configuration given to the target bearing the attribute.
*
*
Nearly all LateBoundDefaults should use this constructor or {@link
* LabelListLateBoundDefault#fromTargetConfiguration}. There are few situations where it isn't
* the appropriate option.
*
*
If you want a late-bound dependency which is configured in the host configuration, just
* use this method with {@link com.google.devtools.build.lib.analysis.config.HostTransition}. If
* you also need to decide the label of the dependency with information gained from the host
* configuration - and it's very unlikely that you do - you can use {@link
* LabelLateBoundDefault#fromHostConfiguration} as well.
*
*
If you want to decide an attribute's value based on the value of its other attributes, use
* a subclass of {@link ComputedDefault}. The only time you should need {@link
* LabelListLateBoundDefault#fromRuleAndAttributesOnly} is if you need access to three or more
* configurable attributes, or if you need to match names with a late-bound attribute on another
* rule.
*
*
If you have a constant-valued attribute, but you need it to have the same name as an
* attribute on another rule which is late-bound, use {@link #alwaysNull}.
*
* @param fragmentClass The fragment to receive from the target configuration. May also be
* BuildConfiguration.class to receive the entire configuration (deprecated) - in this case,
* you must only use methods of BuildConfiguration itself, and not use any fragments.
* @param defaultValue The default {@link Label} to return at loading time, when the
* configuration is not available.
* @param resolver A function which will compute the actual value with the configuration.
*/
public static LabelLateBoundDefault fromTargetConfiguration(
Class fragmentClass, Label defaultValue, Resolver resolver) {
Preconditions.checkArgument(
!fragmentClass.equals(Void.class),
"Use fromRuleAndAttributesOnly to specify a LateBoundDefault which does not use "
+ "configuration.");
return new LabelLateBoundDefault<>(false, fragmentClass, defaultValue, resolver);
}
/**
* Creates a new LateBoundDefault which uses the rule, its configured attributes, and a fragment
* of the host configuration.
*
* This should only be necessary in very specialized cases. In almost all cases, you don't
* need this method, just {@link #fromTargetConfiguration} and {@link
* com.google.devtools.build.lib.analysis.config.HostTransition}.
*
*
This method only affects the configuration fragment passed to {@link #resolve}. You must
* also use {@link com.google.devtools.build.lib.analysis.config.HostTransition}, so that the
* dependency will be analyzed in the host configuration.
*
* @param fragmentClass The fragment to receive from the host configuration. May also be
* BuildConfiguration.class to receive the entire configuration (deprecated) - in this case,
* you must only use methods of BuildConfiguration itself, and not use any fragments. It is
* very rare that a LateBoundDefault should need a host configuration fragment; use {@link
* #fromTargetConfiguration} in most cases.
* @param defaultValue The default {@link Label} to return at loading time, when the
* configuration is not available.
* @param resolver A function which will compute the actual value with the configuration.
*/
public static LabelLateBoundDefault fromHostConfiguration(
Class fragmentClass, Label defaultValue, Resolver resolver) {
Preconditions.checkArgument(
!fragmentClass.equals(Void.class),
"Use fromRuleAndAttributesOnly to specify a LateBoundDefault which does not use "
+ "configuration.");
return new LabelLateBoundDefault<>(true, fragmentClass, defaultValue, resolver);
}
}
/** A {@link LateBoundDefault} for a {@link List} of {@link Label} objects. */
public static class LabelListLateBoundDefault
extends SimpleLateBoundDefault> {
private LabelListLateBoundDefault(
boolean useHostConfiguration,
Class fragmentClass,
Resolver> resolver) {
super(useHostConfiguration, fragmentClass, ImmutableList.of(), resolver);
}
public static LabelListLateBoundDefault fromTargetConfiguration(
Class fragmentClass, Resolver> resolver) {
Preconditions.checkArgument(
!fragmentClass.equals(Void.class),
"Use fromRuleAndAttributesOnly to specify a LateBoundDefault which does not use "
+ "configuration.");
return new LabelListLateBoundDefault<>(false, fragmentClass, resolver);
}
/**
* Creates a new LabelListLateBoundDefault which uses only the rule and its configured
* attributes.
*
* This should only be necessary in very specialized cases. In almost all cases, you don't
* need this method, just use {@link ComputedDefault}.
*
*
This is used primarily for computing values based on three or more configurable attributes
* and/or matching names with late-bound attributes on other rules.
*
* @param resolver A function which will compute the actual value with the configuration.
*/
public static LabelListLateBoundDefault fromRuleAndAttributesOnly(
Resolver> resolver) {
return new LabelListLateBoundDefault<>(false, Void.class, resolver);
}
}
private final String name;
private final Type type;
private final Set propertyFlags;
// Exactly one of these conditions is true:
// 1. defaultValue == null.
// 2. defaultValue instanceof ComputedDefault &&
// type.isValid(defaultValue.getDefault())
// 3. defaultValue instanceof SkylarkComputedDefaultTemplate &&
// type.isValid(defaultValue.computePossibleValues().getDefault())
// 4. type.isValid(defaultValue).
// 5. defaultValue instanceof LateBoundDefault &&
// type.isValid(defaultValue.getDefault(configuration))
// (We assume a hypothetical Type.isValid(Object) predicate.)
private final Object defaultValue;
private final ConfigurationTransition configTransition;
private final SplitTransitionProvider splitTransitionProvider;
/**
* For label or label-list attributes, this predicate returns which rule
* classes are allowed for the targets in the attribute.
*/
private final RuleClassNamePredicate allowedRuleClassesForLabels;
/**
* For label or label-list attributes, this predicate returns which rule
* classes are allowed for the targets in the attribute with warning.
*/
private final RuleClassNamePredicate allowedRuleClassesForLabelsWarning;
/**
* For label or label-list attributes, this predicate returns which file
* types are allowed for targets in the attribute that happen to be file
* targets (rather than rules).
*/
private final FileTypeSet allowedFileTypesForLabels;
/**
* This predicate-like object checks
* if the edge between two rules using this attribute is valid
* in the dependency graph. Returns null if valid, otherwise an error message.
*/
private final ValidityPredicate validityPredicate;
private final Predicate condition;
private final PredicateWithMessage allowedValues;
private final RequiredProviders requiredProviders;
private final ImmutableList> aspects;
/**
* Constructs a rule attribute with the specified name, type and default value.
*
* @param name the name of the attribute
* @param type the type of the attribute
* @param defaultValue the default value to use for this attribute if none is specified in rule
* declaration in the BUILD file. Must be null, or of type "type". May be an instance of
* ComputedDefault, in which case its getDefault() method must return an instance of "type",
* or null. Must be immutable.
* @param configTransition the configuration transition for this attribute (which must be of type
* LABEL, LABEL_LIST, NODEP_LABEL or NODEP_LABEL_LIST).
*/
private Attribute(
String name,
Type type,
Set propertyFlags,
Object defaultValue,
ConfigurationTransition configTransition,
SplitTransitionProvider splitTransitionProvider,
RuleClassNamePredicate allowedRuleClassesForLabels,
RuleClassNamePredicate allowedRuleClassesForLabelsWarning,
FileTypeSet allowedFileTypesForLabels,
ValidityPredicate validityPredicate,
Predicate condition,
PredicateWithMessage allowedValues,
RequiredProviders requiredProviders,
ImmutableList> aspects) {
Preconditions.checkNotNull(configTransition);
Preconditions.checkArgument(
(configTransition == NoTransition.INSTANCE)
|| type.getLabelClass() == LabelClass.DEPENDENCY
|| type.getLabelClass() == LabelClass.NONDEP_REFERENCE,
"Configuration transitions can only be specified for label or label list attributes");
Preconditions.checkArgument(
isLateBound(name) == (defaultValue instanceof LateBoundDefault),
"late bound attributes require a default value that is late bound (and vice versa): %s",
name);
if (isLateBound(name)) {
LateBoundDefault lateBoundDefault = (LateBoundDefault) defaultValue;
Preconditions.checkArgument(!lateBoundDefault.useHostConfiguration()
|| (configTransition.isHostTransition()),
"a late bound default value using the host configuration must use the host transition");
}
this.name = name;
this.type = type;
this.propertyFlags = propertyFlags;
this.defaultValue = defaultValue;
this.configTransition = configTransition;
this.splitTransitionProvider = splitTransitionProvider;
this.allowedRuleClassesForLabels = allowedRuleClassesForLabels;
this.allowedRuleClassesForLabelsWarning = allowedRuleClassesForLabelsWarning;
this.allowedFileTypesForLabels = allowedFileTypesForLabels;
this.validityPredicate = validityPredicate;
this.condition = condition;
this.allowedValues = allowedValues;
this.requiredProviders = requiredProviders;
this.aspects = aspects;
}
/**
* Returns the name of this attribute.
*/
public String getName() {
return name;
}
/**
* Returns the public name of this attribute. This is the name we use in Skylark code
* and we can use it to display to the end-user.
* Implicit and late-bound attributes start with '_' (instead of '$' or ':').
*/
public String getPublicName() {
return getSkylarkName(getName());
}
/**
* Returns the logical type of this attribute. (May differ from the actual
* representation as a value in the build interpreter; for example, an
* attribute may logically be a list of labels, but be represented as a list
* of strings.)
*/
public Type getType() {
return type;
}
private boolean getPropertyFlag(PropertyFlag flag) {
return propertyFlags.contains(flag);
}
/**
* Returns true if this parameter is mandatory.
*/
public boolean isMandatory() {
return getPropertyFlag(PropertyFlag.MANDATORY);
}
/**
* Returns true if this list parameter cannot have an empty list as a value.
*/
public boolean isNonEmpty() {
return getPropertyFlag(PropertyFlag.NON_EMPTY);
}
/**
* Returns true if this label parameter must produce a single artifact.
*/
public boolean isSingleArtifact() {
return getPropertyFlag(PropertyFlag.SINGLE_ARTIFACT);
}
/**
* Returns true if this label type parameter is checked by silent ruleclass filtering.
*/
public boolean isSilentRuleClassFilter() {
return getPropertyFlag(PropertyFlag.SILENT_RULECLASS_FILTER);
}
/**
* Returns true if this label type parameter skips the analysis time filetype check.
*/
public boolean isSkipAnalysisTimeFileTypeCheck() {
return getPropertyFlag(PropertyFlag.SKIP_ANALYSIS_TIME_FILETYPE_CHECK);
}
/**
* Returns true if this parameter is order-independent.
*/
public boolean isOrderIndependent() {
return getPropertyFlag(PropertyFlag.ORDER_INDEPENDENT);
}
/**
* Returns true if output_licenses should be used for checking licensing.
*/
public boolean useOutputLicenses() {
return getPropertyFlag(PropertyFlag.OUTPUT_LICENSES);
}
/**
* Returns the configuration transition for this attribute for label or label
* list attributes. For other attributes it will always return {@code NONE}.
*/
public ConfigurationTransition getConfigurationTransition() {
return configTransition;
}
/**
* Returns the split configuration transition for this attribute.
*
* @param attributeMapper the attribute mapper of the current {@link Rule}
* @return a SplitTransition object
* @throws IllegalStateException if {@link #hasSplitConfigurationTransition} is not true
*/
public SplitTransition getSplitTransition(AttributeMap attributeMapper) {
Preconditions.checkState(hasSplitConfigurationTransition());
return splitTransitionProvider.apply(attributeMapper);
}
/**
* Returns true if this attribute transitions on a split transition.
* See {@link SplitTransition}.
*/
public boolean hasSplitConfigurationTransition() {
return (splitTransitionProvider != null);
}
/**
* Returns whether the target is required to be executable for label or label
* list attributes. For other attributes it always returns {@code false}.
*/
public boolean isExecutable() {
return getPropertyFlag(PropertyFlag.EXECUTABLE);
}
/**
* Returns {@code true} iff the rule is a direct input for an action.
*/
public boolean isDirectCompileTimeInput() {
return getPropertyFlag(PropertyFlag.DIRECT_COMPILE_TIME_INPUT);
}
/**
* Returns {@code true} iff this attribute requires documentation.
*/
public boolean isDocumented() {
return !getPropertyFlag(PropertyFlag.UNDOCUMENTED);
}
/**
* Returns {@code true} iff this attribute should be published to the rule's
* tag set. Note that not all Type classes support tag conversion.
*/
public boolean isTaggable() {
return getPropertyFlag(PropertyFlag.TAGGABLE);
}
public boolean isStrictLabelCheckingEnabled() {
return getPropertyFlag(PropertyFlag.STRICT_LABEL_CHECKING);
}
/**
* Returns true if the value of this attribute should be a part of a given set.
*/
public boolean checkAllowedValues() {
return getPropertyFlag(PropertyFlag.CHECK_ALLOWED_VALUES);
}
public boolean performPrereqValidatorCheck() {
return !getPropertyFlag(PropertyFlag.SKIP_PREREQ_VALIDATOR_CHECKS);
}
public boolean checkConstraintsOverride() {
return getPropertyFlag(PropertyFlag.CHECK_CONSTRAINTS_OVERRIDE);
}
public boolean skipConstraintsOverride() {
return getPropertyFlag(PropertyFlag.SKIP_CONSTRAINTS_OVERRIDE);
}
/**
* Returns true if this attribute's value can be influenced by the build configuration.
*/
public boolean isConfigurable() {
// Output types are excluded because of Rule#populateExplicitOutputFiles.
return !(type.getLabelClass() == LabelClass.OUTPUT
|| getPropertyFlag(PropertyFlag.NONCONFIGURABLE));
}
/**
* Returns a predicate that evaluates to true for rule classes that are allowed labels in this
* attribute. If this is not a label or label-list attribute, the returned predicate always
* evaluates to true.
*
* NOTE: This may return Predicates.alwaysTrue() as a sentinel meaning "do the right
* thing", rather than actually allowing all rule classes in that attribute. Others parts of bazel
* code check for that specific instance.
*/
public Predicate getAllowedRuleClassesPredicate() {
return allowedRuleClassesForLabels.asPredicateOfRuleClass();
}
/**
* Returns a predicate that evaluates to true for rule classes that are
* allowed labels in this attribute. If this is not a label or label-list
* attribute, the returned predicate always evaluates to true.
*/
// TODO(b/69917891) Remove these methods once checkbuilddeps no longer depends on them.
public Predicate getAllowedRuleClassNamesPredicate() {
return allowedRuleClassesForLabels.asPredicateOfRuleClassName();
}
/**
* Returns a predicate that evaluates to true for rule classes that are
* allowed labels in this attribute with warning. If this is not a label or label-list
* attribute, the returned predicate always evaluates to true.
*/
public Predicate getAllowedRuleClassesWarningPredicate() {
return allowedRuleClassesForLabelsWarning.asPredicateOfRuleClass();
}
public RequiredProviders getRequiredProviders() {
return requiredProviders;
}
public FileTypeSet getAllowedFileTypesPredicate() {
return allowedFileTypesForLabels;
}
public ValidityPredicate getValidityPredicate() {
return validityPredicate;
}
public Predicate getCondition() {
return condition == null ? Predicates.alwaysTrue() : condition;
}
public PredicateWithMessage getAllowedValues() {
return allowedValues;
}
/**
* Returns the list of aspects required for dependencies through this attribute.
*/
public ImmutableList getAspects(Rule rule) {
ImmutableList.Builder builder = ImmutableList.builder();
for (RuleAspect aspect : aspects) {
Aspect a = aspect.getAspect(rule);
if (a != null) {
builder.add(a);
}
}
return builder.build();
}
public ImmutableList getAspectClasses() {
ImmutableList.Builder result = ImmutableList.builder();
for (RuleAspect aspect : aspects) {
result.add(aspect.getAspectClass());
}
return result.build();
}
/**
* Returns the default value of this attribute in the context of the
* specified Rule. For attributes with a computed default, i.e. {@code
* hasComputedDefault()}, {@code rule} must be non-null since the result may
* depend on the values of its other attributes.
*
* The result may be null (although this is not a value in the build
* language).
*
*
During population of the rule's attribute dictionary, all non-computed
* defaults must be set before all computed ones.
*
* @param rule the rule to which this attribute belongs; non-null if
* {@code hasComputedDefault()}; ignored otherwise.
*/
public Object getDefaultValue(Rule rule) {
if (!getCondition().apply(rule == null ? null : NonconfigurableAttributeMapper.of(rule))) {
return null;
} else if (defaultValue instanceof LateBoundDefault) {
return ((LateBoundDefault) defaultValue).getDefault();
} else {
return defaultValue;
}
}
/**
* Returns the default value of this attribute, even if it has a condition, is a computed default,
* or a late-bound default.
*/
@VisibleForTesting
public Object getDefaultValueForTesting() {
return defaultValue;
}
public LateBoundDefault getLateBoundDefault() {
Preconditions.checkState(isLateBound());
return (LateBoundDefault) defaultValue;
}
/**
* Returns true iff this attribute has a computed default or a condition.
*
* @see #getDefaultValue(Rule)
*/
boolean hasComputedDefault() {
return (defaultValue instanceof ComputedDefault)
|| (defaultValue instanceof SkylarkComputedDefaultTemplate)
|| (condition != null);
}
/**
* Returns if this attribute is an implicit dependency according to the naming policy that
* designates implicit attributes.
*/
public boolean isImplicit() {
return isImplicit(getName());
}
/**
* Returns if an attribute with the given name is an implicit dependency according to the
* naming policy that designates implicit attributes.
*/
public static boolean isImplicit(String name) {
return name.startsWith("$");
}
/**
* Returns if this attribute is late-bound according to the naming policy that designates
* late-bound attributes.
*/
public boolean isLateBound() {
return isLateBound(getName());
}
/**
* Returns if an attribute with the given name is late-bound according to the naming policy
* that designates late-bound attributes.
*/
public static boolean isLateBound(String name) {
return name.startsWith(":");
}
/** Returns whether this attribute is considered private in Skylark. */
private static boolean isPrivateAttribute(String nativeAttrName) {
return isLateBound(nativeAttrName) || isImplicit(nativeAttrName);
}
/**
* Returns the Skylark-usable name of this attribute.
*
* Implicit and late-bound attributes start with '_' (instead of '$' or ':').
*/
public static String getSkylarkName(String nativeAttrName) {
if (isPrivateAttribute(nativeAttrName)) {
return "_" + nativeAttrName.substring(1);
}
return nativeAttrName;
}
@Override
public String toString() {
return "Attribute(" + name + ", " + type + ")";
}
@Override
public int compareTo(Attribute other) {
return name.compareTo(other.name);
}
/**
* Returns a replica builder of this Attribute.
*/
public Attribute.Builder cloneBuilder(Type tp) {
Preconditions.checkArgument(tp == this.type);
Builder builder = new Builder<>(name, tp);
builder.allowedFileTypesForLabels = allowedFileTypesForLabels;
builder.allowedRuleClassesForLabels = allowedRuleClassesForLabels;
builder.allowedRuleClassesForLabelsWarning = allowedRuleClassesForLabelsWarning;
builder.requiredProvidersBuilder = requiredProviders.copyAsBuilder();
builder.validityPredicate = validityPredicate;
builder.condition = condition;
builder.configTransition = configTransition;
builder.splitTransitionProvider = splitTransitionProvider;
builder.propertyFlags = newEnumSet(propertyFlags, PropertyFlag.class);
builder.value = defaultValue;
builder.valueSet = false;
builder.allowedValues = allowedValues;
builder.aspects = new LinkedHashMap<>();
for (RuleAspect aspect : aspects) {
builder.aspects.put(aspect.getName(), aspect);
}
return builder;
}
public Attribute.Builder cloneBuilder() {
return cloneBuilder(this.type);
}
}