| // 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.android; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.actions.Artifact; |
| import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder; |
| import com.google.devtools.build.lib.analysis.RuleContext; |
| import com.google.devtools.build.lib.analysis.actions.ActionConstructionContext; |
| import com.google.devtools.build.lib.analysis.actions.FileWriteAction; |
| import com.google.devtools.build.lib.analysis.actions.SymlinkAction; |
| import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget; |
| import com.google.devtools.build.lib.cmdline.Label; |
| import com.google.devtools.build.lib.packages.BuildType; |
| import com.google.devtools.build.lib.rules.java.JavaInfo; |
| import com.google.devtools.build.lib.rules.java.JavaPluginInfoProvider; |
| import com.google.devtools.build.lib.rules.java.JavaTargetAttributes; |
| import com.google.devtools.build.lib.syntax.Type; |
| import com.google.devtools.build.lib.util.ResourceFileLoader; |
| import com.google.devtools.build.lib.vfs.PathFragment; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Support logic for Bazel's <a |
| * href="https://developer.android.com/topic/libraries/data-binding/index.html">data binding</a> |
| * integration. |
| * |
| * <p>In short, data binding in Bazel works as follows: |
| * |
| * <ol> |
| * <li>If a rule enables data binding and has layout resources with data binding expressions, |
| * resource processing invokes the data binding library to preprocess these expressions, then |
| * strips them out before feeding the resources into aapt. A separate "layout info" XML file |
| * gets produced that contains the bindings. |
| * <li>The data binding annotation processor gets activated on Java compilation. This processor |
| * reads a custom-generated <code>DataBindingInfo.java</code> which specifies the path to the |
| * layout info file (as an annotation). The processor reads that file and produces the |
| * corresponding Java classes that end-user code uses to access the resources. |
| * <li>The data binding compile-time and runtime support libraries get linked into the binary's |
| * deploy jar. |
| * </ol> |
| * |
| * <p>For data binding to work, the corresponding support libraries must be checked into the depot |
| * via the implicit dependencies specified inside this class. |
| * |
| * <p>Unless otherwise specified, all methods in this class assume the current rule applies data |
| * binding. Callers can intelligently trigger this logic by checking {@link #isEnabled}. |
| */ |
| public final class DataBinding { |
| /** The rule attribute supplying data binding's annotation processor. */ |
| public static final String DATABINDING_ANNOTATION_PROCESSOR_ATTR = |
| "$databinding_annotation_processor"; |
| |
| /** |
| * Annotation processing creates the following metadata files that describe how data binding is |
| * applied. The full file paths include prefixes as implemented in {@link #getMetadataOutputs}. |
| */ |
| private static final ImmutableList<String> METADATA_OUTPUT_SUFFIXES = |
| ImmutableList.<String>of("setter_store.bin", "layoutinfo.bin", "br.bin"); |
| |
| /** The directory where the annotation processor looks for dep metadata. */ |
| private static final String DEP_METADATA_INPUT_DIR = "dependent-lib-artifacts"; |
| |
| /** The directory where the annotation processor write metadata output for the current rule. */ |
| private static final String METADATA_OUTPUT_DIR = "bin-files"; |
| |
| /** |
| * Should data binding support be enabled for this rule? |
| * |
| * <p>Data binding incurs additional resource processing and compilation work as well as |
| * additional compile/runtime dependencies. But rules with data binding disabled will fail if data |
| * binding expressions appear in their layout resources. |
| */ |
| public static boolean isEnabled(RuleContext ruleContext) { |
| return ruleContext.attributes().has("enable_data_binding", Type.BOOLEAN) |
| && ruleContext.attributes().get("enable_data_binding", Type.BOOLEAN); |
| } |
| |
| /** Returns this rule's data binding base output dir (as an execroot-relative path). */ |
| private static PathFragment getDataBindingExecPath(RuleContext ruleContext) { |
| return ruleContext |
| .getBinOrGenfilesDirectory() |
| .getExecPath() |
| .getRelative(ruleContext.getUniqueDirectory("databinding")); |
| } |
| |
| /** Returns an artifact for the specified output under a standardized data binding base dir. */ |
| private static Artifact getDataBindingArtifact(RuleContext ruleContext, String relativePath) { |
| PathFragment binRelativeBasePath = |
| getDataBindingExecPath(ruleContext) |
| .relativeTo(ruleContext.getBinOrGenfilesDirectory().getExecPath()); |
| return ruleContext.getDerivedArtifact( |
| binRelativeBasePath.getRelative(relativePath), ruleContext.getBinOrGenfilesDirectory()); |
| } |
| |
| /** |
| * Returns the file where data binding's resource processing produces binding xml. For example, |
| * given: |
| * |
| * <pre>{@code |
| * <layout> |
| * <data> |
| * <variable name="foo" type="String" /> |
| * </data> |
| * </layout> |
| * <LinearLayout> |
| * ... |
| * </LinearLayout> |
| * }</pre> |
| * |
| * <p>data binding strips out and processes this part: |
| * |
| * <pre>{@code |
| * <data> |
| * <variable name="foo" type="String" /> |
| * </data> |
| * }</pre> |
| * |
| * for each layout file with data binding expressions. Since this may produce multiple files, |
| * outputs are zipped up into a single container. |
| */ |
| static Artifact getLayoutInfoFile(ActionConstructionContext context) { |
| return getSuffixedInfoFile(context, ""); |
| } |
| |
| /** Gets a layout info file with the specified suffix (for use in having different outputs) */ |
| static Artifact getSuffixedInfoFile(ActionConstructionContext context, String suffix) { |
| return context.getUniqueDirectoryArtifact( |
| "databinding", "layout-info" + suffix + ".zip"); |
| } |
| |
| /** |
| * Adds data binding's annotation processor as a plugin to the given Java compilation context. |
| * |
| * <p>This, in conjunction with {@link #createAnnotationFile} extends the Java compilation to |
| * translate data binding .xml into corresponding classes. |
| */ |
| static void addAnnotationProcessor( |
| RuleContext ruleContext, JavaTargetAttributes.Builder attributes) { |
| JavaPluginInfoProvider plugin = |
| JavaInfo.getProvider( |
| JavaPluginInfoProvider.class, |
| ruleContext.getPrerequisite( |
| DATABINDING_ANNOTATION_PROCESSOR_ATTR, RuleConfiguredTarget.Mode.HOST)); |
| |
| for (String name : plugin.getProcessorClasses()) { |
| // For header compilation (see JavaHeaderCompileAction): |
| attributes.addApiGeneratingProcessorName(name); |
| // For full compilation: |
| attributes.addProcessorName(name); |
| } |
| // For header compilation (see JavaHeaderCompileAction): |
| attributes.addApiGeneratingProcessorPath(plugin.getProcessorClasspath()); |
| // For full compilation: |
| attributes.addProcessorPath(plugin.getProcessorClasspath()); |
| attributes.addAdditionalOutputs(getMetadataOutputs(ruleContext)); |
| } |
| |
| /** The javac flags that are needed to configure data binding's annotation processor. */ |
| static ImmutableList<String> getJavacOpts(RuleContext ruleContext, boolean isBinary) { |
| ImmutableList.Builder<String> flags = ImmutableList.builder(); |
| String metadataOutputDir = getDataBindingExecPath(ruleContext).getPathString(); |
| |
| // Directory where the annotation processor looks for deps metadata output. The annotation |
| // processor automatically appends {@link DEP_METADATA_INPUT_DIR} to this path. Individual |
| // files can be anywhere under this directory, recursively. |
| flags.add(createProcessorFlag("bindingBuildFolder", metadataOutputDir)); |
| // Directory where the annotation processor should write this rule's metadata output. The |
| // annotation processor automatically appends {@link METADATA_OUTPUT_DIR} to this path. |
| flags.add(createProcessorFlag("generationalFileOutDir", metadataOutputDir)); |
| // Path to the Android SDK installation (if available). |
| flags.add(createProcessorFlag("sdkDir", "/not/used")); |
| // Whether the current rule is a library or binary. |
| flags.add(createProcessorFlag("artifactType", isBinary ? "APPLICATION" : "LIBRARY")); |
| // The path where data binding's resource processor wrote its output (the data binding XML |
| // expressions). The annotation processor reads this file to translate that XML into Java. |
| flags.add(createProcessorFlag("xmlOutDir", getDataBindingExecPath(ruleContext).toString())); |
| // Unused. |
| flags.add(createProcessorFlag("exportClassListTo", "/tmp/exported_classes")); |
| // The Java package for the current rule. |
| flags.add(createProcessorFlag("modulePackage", AndroidCommon.getJavaPackage(ruleContext))); |
| // The minimum Android SDK compatible with this rule. |
| flags.add(createProcessorFlag("minApi", "14")); // TODO(gregce): update this |
| // If enabled, the annotation processor reports detailed output about its activities. |
| // addProcessorFlag(attributes, "enableDebugLogs", "1"); |
| // If enabled, produces cleaner output for Android Studio. |
| flags.add(createProcessorFlag("printEncodedErrors", "0")); |
| // Specifies whether the current rule is a test. Currently unused. |
| // addDataBindingProcessorFlag(attributes, "isTestVariant", "false"); |
| // Specifies that data binding is only used for test instrumentation. Currently unused. |
| // addDataBindingProcessorFlag(attributes, "enableForTests", null); |
| return flags.build(); |
| } |
| |
| /** Turns a key/value pair into a javac annotation processor flag received by data binding. */ |
| private static String createProcessorFlag(String flag, String value) { |
| return String.format("-Aandroid.databinding.%s=%s", flag, value); |
| } |
| |
| /** |
| * Creates and returns the generated Java source that data binding's annotation processor reads to |
| * translate layout info xml (from {@link #getLayoutInfoFile} into the classes that end user code |
| * consumes. |
| * |
| * <p>This mostly just triggers the annotation processor. Annotation processor settings are |
| * configured separately in {@link #getJavacopts}. |
| */ |
| static Artifact createAnnotationFile(RuleContext ruleContext) { |
| String contents; |
| try { |
| contents = |
| ResourceFileLoader.loadResource(DataBinding.class, "databinding_annotation_template.txt"); |
| } catch (IOException e) { |
| ruleContext.ruleError("Cannot load annotation processor template: " + e.getMessage()); |
| return null; |
| } |
| Artifact output = getDataBindingArtifact(ruleContext, "DataBindingInfo.java"); |
| ruleContext.registerAction(FileWriteAction.create(ruleContext, output, contents, false)); |
| return output; |
| } |
| |
| /** |
| * Adds the appropriate {@link UsesDataBindingProvider} for a rule if it should expose one. |
| * |
| * <p>A rule exposes {@link UsesDataBindingProvider} if either it or its deps set {@code |
| * enable_data_binding = 1}. |
| */ |
| public static void maybeAddProvider( |
| RuleConfiguredTargetBuilder builder, RuleContext ruleContext) { |
| // Expose the data binding provider if this rule either applies data binding or exports a dep |
| // that applies it. |
| List<Artifact> dataBindingMetadataOutputs = new ArrayList<>(); |
| if (DataBinding.isEnabled(ruleContext)) { |
| dataBindingMetadataOutputs.addAll(getMetadataOutputs(ruleContext)); |
| } |
| dataBindingMetadataOutputs.addAll(getTransitiveMetadata(ruleContext, "exports")); |
| if (!AndroidResources.definesAndroidResources(ruleContext.attributes())) { |
| // If this rule doesn't declare direct resources, no resource processing is run so no data |
| // binding outputs are produced. In that case, we need to explicitly propagate data binding |
| // outputs from the deps to make sure they continue up the build graph. |
| dataBindingMetadataOutputs.addAll(getTransitiveMetadata(ruleContext, "deps")); |
| } |
| if (!dataBindingMetadataOutputs.isEmpty()) { |
| builder.addProvider( |
| UsesDataBindingProvider.class, new UsesDataBindingProvider(dataBindingMetadataOutputs)); |
| } |
| } |
| |
| /** Returns the data binding resource processing output from deps under the given attribute. */ |
| private static List<Artifact> getTransitiveMetadata(RuleContext ruleContext, String attr) { |
| ImmutableList.Builder<Artifact> dataBindingMetadataOutputs = ImmutableList.builder(); |
| if (ruleContext.attributes().has(attr, BuildType.LABEL_LIST)) { |
| for (UsesDataBindingProvider provider : |
| ruleContext.getPrerequisites( |
| attr, RuleConfiguredTarget.Mode.TARGET, UsesDataBindingProvider.class)) { |
| dataBindingMetadataOutputs.addAll(provider.getMetadataOutputs()); |
| } |
| } |
| return dataBindingMetadataOutputs.build(); |
| } |
| |
| /** |
| * Returns metadata outputs from this rule's annotation processing that describe what it did with |
| * data binding. This is used by parent rules to ensure consistent binding patterns. |
| * |
| * <p>>For example, if {@code foo.AndroidBinary} depends on {@code foo.lib.AndroidLibrary} and the |
| * library defines data binding expression {@code Bar}, compiling the library produces Java class |
| * {@code foo.lib.Bar}. But since the binary applies data binding over the merged resources of its |
| * deps, that means the binary also sees {@code Bar}, so it compiles it into {@code foo.Bar}. This |
| * would be a class redefinition conflict. But by feeding the library's metadata outputs into the |
| * binary's compilation, enough information is available to only use the first version. |
| */ |
| private static List<Artifact> getMetadataOutputs(RuleContext ruleContext) { |
| if (!AndroidResources.definesAndroidResources(ruleContext.attributes())) { |
| // If this rule doesn't define local resources, no resource processing was done, so it |
| // doesn't produce data binding output. |
| return ImmutableList.<Artifact>of(); |
| } |
| ImmutableList.Builder<Artifact> outputs = ImmutableList.<Artifact>builder(); |
| String javaPackage = AndroidCommon.getJavaPackage(ruleContext); |
| for (String suffix : METADATA_OUTPUT_SUFFIXES) { |
| // The annotation processor automatically creates files with this naming pattern under the |
| // {@code -Aandroid.databinding.generationalFileOutDir} base directory. |
| outputs.add( |
| getDataBindingArtifact( |
| ruleContext, |
| String.format("%s/%s-%s-%s", METADATA_OUTPUT_DIR, javaPackage, javaPackage, suffix))); |
| } |
| return outputs.build(); |
| } |
| |
| /** |
| * Processes deps that also apply data binding. |
| * |
| * @param ruleContext the current rule |
| * @return the deps' metadata outputs. These need to be staged as compilation inputs to the |
| * current rule. |
| */ |
| static ImmutableList<Artifact> processDeps(RuleContext ruleContext) { |
| ImmutableList.Builder<Artifact> dataBindingJavaInputs = ImmutableList.<Artifact>builder(); |
| if (AndroidResources.definesAndroidResources(ruleContext.attributes())) { |
| dataBindingJavaInputs.add(DataBinding.getLayoutInfoFile(ruleContext)); |
| } |
| for (Artifact dataBindingDepMetadata : getTransitiveMetadata(ruleContext, "deps")) { |
| dataBindingJavaInputs.add( |
| symlinkDepsMetadataIntoOutputTree(ruleContext, dataBindingDepMetadata)); |
| } |
| return dataBindingJavaInputs.build(); |
| } |
| |
| /** |
| * Data binding's annotation processor reads the transitive metadata outputs of the target's deps |
| * (see {@link #getMetadataOutputs(RuleContext)}) in the directory specified by the processor flag |
| * {@code -Aandroid.databinding.bindingBuildFolder}. Since dependencies don't generate their |
| * outputs under a common directory, we symlink them into a common place here. |
| * |
| * @return the symlink paths of the transitive dep metadata outputs for this rule |
| */ |
| private static Artifact symlinkDepsMetadataIntoOutputTree( |
| RuleContext ruleContext, Artifact depMetadata) { |
| Label ruleLabel = ruleContext.getRule().getLabel(); |
| Artifact symlink = |
| getDataBindingArtifact( |
| ruleContext, |
| String.format( |
| "%s/%s", DEP_METADATA_INPUT_DIR, depMetadata.getRootRelativePathString())); |
| ruleContext.registerAction( |
| new SymlinkAction( |
| ruleContext.getActionOwner(), |
| depMetadata, |
| symlink, |
| String.format( |
| "Symlinking dep metadata output %s for %s", depMetadata.getFilename(), ruleLabel))); |
| return symlink; |
| } |
| } |