// Copyright 2016 The Bazel Authors. 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.objc; import static com.google.devtools.build.lib.packages.Attribute.attr; import static com.google.devtools.build.lib.packages.BuildType.LABEL_KEYED_STRING_DICT; import static com.google.devtools.build.lib.packages.BuildType.LABEL_LIST; import static com.google.devtools.build.lib.packages.ImplicitOutputsFunction.fromTemplates; import com.google.common.collect.ImmutableList; import com.google.devtools.build.lib.analysis.BaseRuleClasses; import com.google.devtools.build.lib.analysis.RuleDefinition; import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment; import com.google.devtools.build.lib.analysis.config.ComposingRuleTransitionFactory; import com.google.devtools.build.lib.packages.ImplicitOutputsFunction; import com.google.devtools.build.lib.packages.ImplicitOutputsFunction.SafeImplicitOutputsFunction; import com.google.devtools.build.lib.packages.RuleClass; import com.google.devtools.build.lib.packages.RuleClass.Builder; import com.google.devtools.build.lib.rules.apple.AppleConfiguration; import com.google.devtools.build.lib.rules.config.ConfigFeatureFlagProvider; import com.google.devtools.build.lib.rules.config.ConfigFeatureFlagTransitionFactory; import com.google.devtools.build.lib.rules.cpp.CppConfiguration; /** * Rule definition for apple_static_library. */ public class AppleStaticLibraryRule implements RuleDefinition { private final ObjcProtoAspect objcProtoAspect; public AppleStaticLibraryRule(ObjcProtoAspect objcProtoAspect) { this.objcProtoAspect = objcProtoAspect; } /** * Template for the fat archive output (using Apple's "lipo" tool to combine .a archive files of * multiple architectures). */ static final SafeImplicitOutputsFunction LIPO_ARCHIVE = fromTemplates("%{name}_lipo.a"); /** * Attribute name for dependent libraries which should not be linked into the outputs of this * rule. */ static final String AVOID_DEPS_ATTR_NAME = "avoid_deps"; @Override public RuleClass build(Builder builder, RuleDefinitionEnvironment env) { MultiArchSplitTransitionProvider splitTransitionProvider = new MultiArchSplitTransitionProvider(); return builder .requiresConfigurationFragments( ObjcConfiguration.class, J2ObjcConfiguration.class, AppleConfiguration.class, CppConfiguration.class) /*
A list of targets which should not be included (nor their transitive dependencies
included) in the outputs of this rule -- even if they are otherwise transitively depended
on via the deps
attribute.
This attribute effectively serves to remove portions of the dependency tree from a static library, and is useful most commonly in scenarios where static libraries depend on each other.
That is, suppose static libraries X and C are typically distributed to consumers
separately. C is a very-common base library, and X contains less-common functionality; X
depends on C, such that applications seeking to import library X must also import library
C. The target describing X would set C's target in avoid_deps
. In this way,
X can depend on C without also containing C. Without this avoid_deps
usage,
an application importing both X and C would have duplicate symbols for C.
name_lipo.a
: a 'lipo'ed archive file. All transitive
dependencies and srcs
are linked, minus all transitive dependencies
specified in avoid_deps
.This rule produces single- or multi-architecture ("fat") Objective-C statically-linked libraries, typically used in creating static Apple Frameworks for distribution and re-use in multiple extensions or applications.
The lipo
tool is used to combine files of multiple architectures; a build flag
controls which architectures are targeted. The build flag examined depends on the
platform_type
attribute for this rule (and is described in its documentation).