// Copyright 2014 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.rules;
import static com.google.devtools.build.lib.syntax.SkylarkFunction.castList;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.packages.Attribute;
import com.google.devtools.build.lib.packages.Attribute.ConfigurationTransition;
import com.google.devtools.build.lib.packages.Attribute.SkylarkLateBound;
import com.google.devtools.build.lib.packages.SkylarkFileType;
import com.google.devtools.build.lib.packages.Type;
import com.google.devtools.build.lib.packages.Type.ConversionException;
import com.google.devtools.build.lib.syntax.Environment;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.syntax.FuncallExpression;
import com.google.devtools.build.lib.syntax.Label;
import com.google.devtools.build.lib.syntax.SkylarkBuiltin;
import com.google.devtools.build.lib.syntax.SkylarkBuiltin.Param;
import com.google.devtools.build.lib.syntax.SkylarkCallbackFunction;
import com.google.devtools.build.lib.syntax.SkylarkEnvironment;
import com.google.devtools.build.lib.syntax.SkylarkFunction;
import com.google.devtools.build.lib.syntax.SkylarkList;
import com.google.devtools.build.lib.syntax.SkylarkModule;
import com.google.devtools.build.lib.syntax.UserDefinedFunction;
import com.google.devtools.build.lib.util.FileTypeSet;
import java.util.Map;
/**
* A helper class to provide Attr module in Skylark.
*/
@SkylarkModule(name = "attr", namespace = true, onlyLoadingPhase = true,
doc = "Module for creating new attributes. "
+ "They are only for use with the rule
function.")
public final class SkylarkAttr {
private static final String MANDATORY_DOC =
"set to True if users have to explicitely specify the value";
private static final String ALLOW_FILES_DOC =
"whether File targets are allowed. Can be True, False (default), or "
+ "a FileType filter.";
private static final String ALLOW_RULES_DOC =
"which rule targets (name of the classes) are allowed. This is deprecated (kept only for "
+ "compatiblity), use providers instead.";
private static final String FLAGS_DOC =
"deprecated, will be removed";
private static final String DEFAULT_DOC =
"sets the default value of the attribute.";
private static final String CONFIGURATION_DOC =
"configuration of the attribute. "
+ "For example, use DATA_CFG or HOST_CFG.";
private static final String EXECUTABLE_DOC =
"set to True if the labels have to be executable. This means the label must refer to an "
+ "executable file, or to a rule that outputs an executable file. Access the labels with "
+ "ctx.executable.<attribute_name>
.";
private static Attribute.Builder> createAttribute(Type> type, Map arguments,
FuncallExpression ast, SkylarkEnvironment env) throws EvalException, ConversionException {
final Location loc = ast.getLocation();
// We use an empty name now so that we can set it later.
// This trick makes sense only in the context of Skylark (builtin rules should not use it).
Attribute.Builder> builder = Attribute.attr("", type);
Object defaultValue = arguments.get("default");
if (defaultValue != null) {
if (defaultValue instanceof UserDefinedFunction) {
// Late bound attribute. Non label type attributes already caused a type check error.
builder.value(new SkylarkLateBound(
new SkylarkCallbackFunction((UserDefinedFunction) defaultValue, ast, env)));
} else {
builder.defaultValue(defaultValue);
}
}
for (String flag : castList(arguments.get("flags"), String.class)) {
builder.setPropertyFlag(flag);
}
if (arguments.containsKey("mandatory") && (Boolean) arguments.get("mandatory")) {
builder.setPropertyFlag("MANDATORY");
}
if (arguments.containsKey("executable") && (Boolean) arguments.get("executable")) {
builder.setPropertyFlag("EXECUTABLE");
}
if (arguments.containsKey("single_file") && (Boolean) arguments.get("single_file")) {
builder.setPropertyFlag("SINGLE_ARTIFACT");
}
if (arguments.containsKey("allow_files")) {
Object fileTypesObj = arguments.get("allow_files");
if (fileTypesObj == Boolean.TRUE) {
builder.allowedFileTypes(FileTypeSet.ANY_FILE);
} else if (fileTypesObj == Boolean.FALSE) {
builder.allowedFileTypes(FileTypeSet.NO_FILE);
} else if (fileTypesObj instanceof SkylarkFileType) {
builder.allowedFileTypes(((SkylarkFileType) fileTypesObj).getFileTypeSet());
} else {
throw new EvalException(loc, "allow_files should be a boolean or a filetype object.");
}
} else if (type.equals(Type.LABEL) || type.equals(Type.LABEL_LIST)) {
builder.allowedFileTypes(FileTypeSet.NO_FILE);
}
Object ruleClassesObj = arguments.get("allow_rules");
if (ruleClassesObj != null) {
builder.allowedRuleClasses(castList(ruleClassesObj, String.class,
"allowed rule classes for attribute definition"));
}
if (arguments.containsKey("providers")) {
builder.mandatoryProviders(castList(arguments.get("providers"), String.class));
}
if (arguments.containsKey("cfg")) {
builder.cfg((ConfigurationTransition) arguments.get("cfg"));
}
return builder;
}
private static Object createAttribute(Map kwargs, Type> type,
FuncallExpression ast, Environment env) throws EvalException {
try {
return createAttribute(type, kwargs, ast, (SkylarkEnvironment) env);
} catch (ConversionException e) {
throw new EvalException(ast.getLocation(), e.getMessage());
}
}
@SkylarkBuiltin(name = "int", doc =
"Creates an attribute of type int.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = Integer.class,
doc = DEFAULT_DOC + " If not specified, default is 0."),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction integer = new SkylarkFunction("int") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.INTEGER, ast, env);
}
};
@SkylarkBuiltin(name = "string", doc =
"Creates an attribute of type string.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = String.class,
doc = DEFAULT_DOC + " If not specified, default is \"\"."),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction string = new SkylarkFunction("string") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.STRING, ast, env);
}
};
@SkylarkBuiltin(name = "label", doc =
"Creates an attribute of type Label. "
+ "It is the only way to specify a dependency to another target. "
+ "If you need a dependency that the user cannot overwrite, make the attribute "
+ "private (starts with _
).",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = Label.class, callbackEnabled = true,
doc = DEFAULT_DOC + " If not specified, default is None. "
+ "Use the Label
function to specify a default value."),
@Param(name = "executable", type = Boolean.class, doc = EXECUTABLE_DOC),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "allow_files", doc = ALLOW_FILES_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "providers", type = SkylarkList.class, generic1 = String.class,
doc = "mandatory providers every dependency has to have"),
@Param(name = "allow_rules", type = SkylarkList.class, generic1 = String.class,
doc = ALLOW_RULES_DOC),
@Param(name = "single_file", doc =
"if True, the label must correspond to a single File. "
+ "Access it through ctx.file.<attribute_name>
."),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction label = new SkylarkFunction("label") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.LABEL, ast, env);
}
};
@SkylarkBuiltin(name = "string_list", doc =
"Creates an attribute of type list of strings",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = SkylarkList.class, generic1 = String.class,
doc = DEFAULT_DOC + " If not specified, default is []."),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class,
doc = CONFIGURATION_DOC)})
private static SkylarkFunction stringList = new SkylarkFunction("string_list") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.STRING_LIST, ast, env);
}
};
@SkylarkBuiltin(name = "label_list", doc =
"Creates an attribute of type list of labels. "
+ "See label
for more information.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = SkylarkList.class, generic1 = Label.class,
callbackEnabled = true,
doc = DEFAULT_DOC + " If not specified, default is []. "
+ "Use the Label
function to specify a default value."),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "allow_files", doc = ALLOW_FILES_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "allow_rules", type = SkylarkList.class, generic1 = String.class,
doc = ALLOW_RULES_DOC),
@Param(name = "providers", type = SkylarkList.class, generic1 = String.class,
doc = "mandatory providers every dependency has to have"),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction labelList = new SkylarkFunction("label_list") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.LABEL_LIST, ast, env);
}
};
@SkylarkBuiltin(name = "bool", doc =
"Creates an attribute of type bool. Its default value is False.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = Boolean.class, doc = DEFAULT_DOC),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction bool = new SkylarkFunction("bool") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.BOOLEAN, ast, env);
}
};
@SkylarkBuiltin(name = "output", doc =
"Creates an attribute of type output. Its default value is None. "
+ "The user provides a file name (string) and the rule must create an action that "
+ "generates the file.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = Label.class, doc = DEFAULT_DOC),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction output = new SkylarkFunction("output") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.OUTPUT, ast, env);
}
};
@SkylarkBuiltin(name = "output_list", doc =
"Creates an attribute of type list of outputs. Its default value is []. "
+ "See output
above for more information.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = SkylarkList.class, generic1 = Label.class, doc = DEFAULT_DOC),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction outputList = new SkylarkFunction("output_list") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.OUTPUT_LIST, ast, env);
}
};
@SkylarkBuiltin(name = "string_dict", doc =
"Creates an attribute of type dictionary, mapping from string to string. "
+ "Its default value is {}.",
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", type = Map.class, doc = DEFAULT_DOC),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction stringDict = new SkylarkFunction("string_dict") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.STRING_DICT, ast, env);
}
};
@SkylarkBuiltin(name = "license", doc =
"Creates an attribute of type license. Its default value is NO_LICENSE.",
// TODO(bazel-team): Implement proper license support for Skylark.
objectType = SkylarkAttr.class,
returnType = Attribute.class,
optionalParams = {
@Param(name = "default", doc = DEFAULT_DOC),
@Param(name = "flags", type = SkylarkList.class, generic1 = String.class, doc = FLAGS_DOC),
@Param(name = "mandatory", type = Boolean.class, doc = MANDATORY_DOC),
@Param(name = "cfg", type = ConfigurationTransition.class, doc = CONFIGURATION_DOC)})
private static SkylarkFunction license = new SkylarkFunction("license") {
@Override
public Object call(Map kwargs, FuncallExpression ast, Environment env)
throws EvalException {
return createAttribute(kwargs, Type.LICENSE, ast, env);
}
};
}