// Copyright 2014 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.cpp;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Optional;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.ActionExecutionContext;
import com.google.devtools.build.lib.actions.ActionOwner;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.Artifact.ArtifactExpander;
import com.google.devtools.build.lib.analysis.actions.AbstractFileWriteAction;
import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
import com.google.devtools.build.lib.util.Fingerprint;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
/**
* Creates C++ module map artifact genfiles. These are then passed to Clang to
* do dependency checking.
*/
@Immutable
public final class CppModuleMapAction extends AbstractFileWriteAction {
private static final String GUID = "4f407081-1951-40c1-befc-d6b4daff5de3";
// C++ module map of the current target
private final CppModuleMap cppModuleMap;
/**
* If set, the paths in the module map are relative to the current working directory instead
* of relative to the module map file's location.
*/
private final boolean moduleMapHomeIsCwd;
// Data required to build the actual module map.
// NOTE: If you add a field here, you'll likely need to add it to the cache key in computeKey().
private final ImmutableList<Artifact> privateHeaders;
private final ImmutableList<Artifact> publicHeaders;
private final ImmutableList<CppModuleMap> dependencies;
private final ImmutableList<PathFragment> additionalExportedHeaders;
private final boolean compiledModule;
private final boolean generateSubmodules;
private final boolean externDependencies;
public CppModuleMapAction(
ActionOwner owner,
CppModuleMap cppModuleMap,
Iterable<Artifact> privateHeaders,
Iterable<Artifact> publicHeaders,
Iterable<CppModuleMap> dependencies,
Iterable<PathFragment> additionalExportedHeaders,
boolean compiledModule,
boolean moduleMapHomeIsCwd,
boolean generateSubmodules,
boolean externDependencies) {
super(
owner,
ImmutableList.<Artifact>builder()
.addAll(Iterables.filter(privateHeaders, Artifact.IS_TREE_ARTIFACT))
.addAll(Iterables.filter(publicHeaders, Artifact.IS_TREE_ARTIFACT))
.build(),
cppModuleMap.getArtifact(),
/*makeExecutable=*/false);
this.cppModuleMap = cppModuleMap;
this.moduleMapHomeIsCwd = moduleMapHomeIsCwd;
this.privateHeaders = ImmutableList.copyOf(privateHeaders);
this.publicHeaders = ImmutableList.copyOf(publicHeaders);
this.dependencies = ImmutableList.copyOf(dependencies);
this.additionalExportedHeaders = ImmutableList.copyOf(additionalExportedHeaders);
this.compiledModule = compiledModule;
this.generateSubmodules = generateSubmodules;
this.externDependencies = externDependencies;
}
@Override
public DeterministicWriter newDeterministicWriter(ActionExecutionContext ctx) {
final ArtifactExpander artifactExpander = ctx.getArtifactExpander();
return new DeterministicWriter() {
@Override
public void writeOutputFile(OutputStream out) throws IOException {
StringBuilder content = new StringBuilder();
PathFragment fragment = cppModuleMap.getArtifact().getExecPath();
int segmentsToExecPath = fragment.segmentCount() - 1;
Optional<Artifact> umbrellaHeader = cppModuleMap.getUmbrellaHeader();
// For details about the different header types, see:
// http://clang.llvm.org/docs/Modules.html#header-declaration
String leadingPeriods = moduleMapHomeIsCwd ? "" : Strings.repeat("../", segmentsToExecPath);
content.append("module \"").append(cppModuleMap.getName()).append("\" {\n");
content.append(" export *\n");
HashSet<PathFragment> deduper = new HashSet<>();
if (umbrellaHeader.isPresent()) {
appendHeader(
content,
"",
umbrellaHeader.get().getExecPath(),
leadingPeriods,
/*canCompile=*/ false,
deduper,
/*isUmbrellaHeader*/ true);
} else {
for (Artifact artifact : expandedHeaders(artifactExpander, publicHeaders)) {
appendHeader(
content,
"",
artifact.getExecPath(),
leadingPeriods,
/*canCompile=*/ true,
deduper,
/*isUmbrellaHeader*/ false);
}
for (Artifact artifact : expandedHeaders(artifactExpander, privateHeaders)) {
appendHeader(
content,
"private",
artifact.getExecPath(),
leadingPeriods,
/*canCompile=*/ true,
deduper,
/*isUmbrellaHeader*/ false);
}
for (PathFragment additionalExportedHeader : additionalExportedHeaders) {
appendHeader(
content,
"",
additionalExportedHeader,
leadingPeriods,
/*canCompile*/ false,
deduper,
/*isUmbrellaHeader*/ false);
}
}
for (CppModuleMap dep : dependencies) {
content.append(" use \"").append(dep.getName()).append("\"\n");
}
content.append("}");
if (externDependencies) {
for (CppModuleMap dep : dependencies) {
content
.append("\nextern module \"")
.append(dep.getName())
.append("\" \"")
.append(leadingPeriods)
.append(dep.getArtifact().getExecPath())
.append("\"");
}
}
out.write(content.toString().getBytes(StandardCharsets.ISO_8859_1));
}
};
}
private static Iterable<Artifact> expandedHeaders(ArtifactExpander artifactExpander,
Iterable<Artifact> unexpandedHeaders) {
List<Artifact> expandedHeaders = new ArrayList<>();
for (Artifact unexpandedHeader : unexpandedHeaders) {
if (unexpandedHeader.isTreeArtifact()) {
artifactExpander.expand(unexpandedHeader, expandedHeaders);
} else {
expandedHeaders.add(unexpandedHeader);
}
}
return ImmutableList.copyOf(expandedHeaders);
}
private void appendHeader(StringBuilder content, String visibilitySpecifier, PathFragment path,
String leadingPeriods, boolean canCompile, HashSet<PathFragment> deduper,
boolean isUmbrellaHeader) {
if (deduper.contains(path)) {
return;
}
deduper.add(path);
if (isUmbrellaHeader) {
content.append(" umbrella header \"umbrella.h\"\n");
return;
}
if (generateSubmodules) {
content.append(" module \"").append(path).append("\" {\n");
content.append(" export *\n ");
}
content.append(" ");
if (!visibilitySpecifier.isEmpty()) {
content.append(visibilitySpecifier).append(" ");
}
if (!canCompile || !shouldCompileHeader(path)) {
content.append("textual ");
}
content.append("header \"").append(leadingPeriods).append(path).append("\"");
if (generateSubmodules) {
content.append("\n }");
}
content.append("\n");
}
private boolean shouldCompileHeader(PathFragment path) {
return compiledModule && !CppFileTypes.CPP_TEXTUAL_INCLUDE.matches(path);
}
@Override
public String getMnemonic() {
return "CppModuleMap";
}
@Override
protected String computeKey() {
Fingerprint f = new Fingerprint();
f.addString(GUID);
f.addInt(privateHeaders.size());
for (Artifact artifact : privateHeaders) {
f.addPath(artifact.getExecPath());
}
f.addInt(publicHeaders.size());
for (Artifact artifact : publicHeaders) {
f.addPath(artifact.getExecPath());
}
f.addInt(dependencies.size());
for (CppModuleMap dep : dependencies) {
f.addPath(dep.getArtifact().getExecPath());
}
f.addInt(additionalExportedHeaders.size());
for (PathFragment path : additionalExportedHeaders) {
f.addPath(path);
}
f.addPath(cppModuleMap.getArtifact().getExecPath());
Optional<Artifact> umbrellaHeader = cppModuleMap.getUmbrellaHeader();
if (umbrellaHeader.isPresent()) {
f.addPath(umbrellaHeader.get().getExecPath());
}
f.addString(cppModuleMap.getName());
f.addBoolean(moduleMapHomeIsCwd);
f.addBoolean(compiledModule);
f.addBoolean(generateSubmodules);
f.addBoolean(externDependencies);
return f.hexDigestAndReset();
}
@VisibleForTesting
public Collection<Artifact> getPublicHeaders() {
return publicHeaders;
}
@VisibleForTesting
public Collection<Artifact> getPrivateHeaders() {
return privateHeaders;
}
@VisibleForTesting
public ImmutableList<PathFragment> getAdditionalExportedHeaders() {
return additionalExportedHeaders;
}
@VisibleForTesting
public Collection<Artifact> getDependencyArtifacts() {
List<Artifact> artifacts = new ArrayList<>();
for (CppModuleMap map : dependencies) {
artifacts.add(map.getArtifact());
}
return artifacts;
}
}