| // 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.databinding; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.actions.Artifact; |
| 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.packages.Type; |
| import com.google.devtools.build.lib.rules.android.AndroidCommon; |
| import com.google.devtools.build.lib.rules.android.AndroidConfiguration; |
| import com.google.devtools.build.lib.rules.android.AndroidDataContext; |
| import com.google.devtools.build.lib.rules.android.AndroidResources; |
| import com.google.devtools.build.lib.util.ResourceFileLoader; |
| import com.google.devtools.build.lib.vfs.PathFragment; |
| import java.io.IOException; |
| import java.util.List; |
| import javax.annotation.Nullable; |
| |
| /** |
| * 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. |
| */ |
| public final class DataBinding { |
| |
| /** The rule attribute supplying data binding's annotation processor. */ |
| public static final String DATABINDING_ANNOTATION_PROCESSOR_ATTR = |
| "$databinding_annotation_processor"; |
| |
| /** The rule attribute supplying data binding's build helper (exec). */ |
| public static final String DATABINDING_EXEC_PROCESSOR_ATTR = "$databinding_exec"; |
| |
| private static final String ENABLE_DATA_BINDING_ATTR = "enable_data_binding"; |
| |
| /** The directory where the annotation processor looks for dep metadata. */ |
| public static final String DEP_METADATA_INPUT_DIR = "dependent-lib-artifacts"; |
| |
| /** The directory where the annotation processor writes metadata output for the current rule. */ |
| public static final String METADATA_OUTPUT_DIR = "bin-files"; |
| |
| @VisibleForTesting |
| public static final DataBindingContext DISABLED_V1_CONTEXT = new DisabledDataBindingV1Context(); |
| |
| private static final DataBindingContext DISABLED_V2_CONTEXT = new DisabledDataBindingV2Context(); |
| |
| /** Supplies a databinding context from a rulecontext. */ |
| public static DataBindingContext contextFrom( |
| RuleContext ruleContext, AndroidConfiguration androidConfig) { |
| |
| return contextFrom(isEnabled(ruleContext), ruleContext, androidConfig); |
| } |
| |
| /** Supplies a databinding context from an action context. */ |
| public static DataBindingContext contextFrom( |
| boolean enabled, ActionConstructionContext context, AndroidConfiguration androidConfig) { |
| |
| if (enabled) { |
| if (androidConfig.useDataBindingV2()) { |
| return new DataBindingV2Context(context, androidConfig.useDataBindingUpdatedArgs()); |
| } else { |
| return new DataBindingV1Context(context, androidConfig.useDataBindingUpdatedArgs()); |
| } |
| } else { |
| if (androidConfig.useDataBindingV2()) { |
| return DISABLED_V2_CONTEXT; |
| } else { |
| return DISABLED_V1_CONTEXT; |
| } |
| } |
| } |
| |
| /** |
| * 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. |
| */ |
| private static boolean isEnabled(RuleContext ruleContext) { |
| return ruleContext.attributes().has(ENABLE_DATA_BINDING_ATTR, Type.BOOLEAN) |
| && Boolean.TRUE.equals( |
| ruleContext.attributes().get(ENABLE_DATA_BINDING_ATTR, Type.BOOLEAN)); |
| } |
| |
| /** Supplies a disabled (no-op) DataBindingContext. */ |
| public static DataBindingContext getDisabledDataBindingContext(AndroidDataContext ctx) { |
| if (ctx.useDataBindingV2()) { |
| return DISABLED_V2_CONTEXT; |
| } else { |
| return DISABLED_V1_CONTEXT; |
| } |
| } |
| |
| /** Returns this rule's data binding base output dir (as an execroot-relative path). */ |
| static PathFragment getDataBindingExecPath(RuleContext ruleContext) { |
| return ruleContext |
| .getBinOrGenfilesDirectory() |
| .getExecPath() |
| .getRelative(ruleContext.getUniqueDirectory("databinding")); |
| } |
| |
| @VisibleForTesting |
| public static Artifact getLayoutInfoFile(ActionConstructionContext actionConstructionContext) { |
| return actionConstructionContext.getUniqueDirectoryArtifact("databinding", "layout-info.zip"); |
| } |
| |
| /** Returns an artifact for the specified output under a standardized data binding base dir. */ |
| static Artifact getDataBindingArtifact(RuleContext ruleContext, String relativePath) { |
| PathFragment binRelativeBasePath = |
| getDataBindingExecPath(ruleContext) |
| .relativeTo(ruleContext.getBinOrGenfilesDirectory().getExecPath()); |
| return ruleContext.getDerivedArtifact( |
| binRelativeBasePath.getRelative(relativePath), ruleContext.getBinOrGenfilesDirectory()); |
| } |
| |
| static ImmutableList<Artifact> getAnnotationFile(RuleContext ruleContext) { |
| // Add this rule's annotation processor input. If the rule doesn't have direct resources, |
| // there's no direct data binding info, so there's strictly no need for annotation processing. |
| // But it's still important to process the deps' .bin files so any Java class references get |
| // re-referenced so they don't get filtered out of the compilation classpath by JavaBuilder |
| // (which filters out classpath .jars that "aren't used": see --reduce_classpath). If data |
| // binding didn't reprocess a library's data binding expressions redundantly up the dependency |
| // chain (meaning each depender processes them again as if they were its own), this problem |
| // wouldn't happen. |
| try { |
| String contents = |
| ResourceFileLoader.loadResource( |
| DataBinding.class, "databinding_annotation_template.txt"); |
| Artifact annotationFile = getDataBindingArtifact(ruleContext, "DataBindingInfo.java"); |
| ruleContext.registerAction( |
| FileWriteAction.create(ruleContext, annotationFile, contents, false)); |
| return ImmutableList.of(annotationFile); |
| } catch (IOException e) { |
| ruleContext.ruleError("Cannot load annotation processor template: " + e.getMessage()); |
| return ImmutableList.of(); |
| } |
| } |
| |
| /** Returns the data binding resource processing output from deps under the given attribute. */ |
| 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.PROVIDER)) { |
| 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. |
| */ |
| static ImmutableList<Artifact> getMetadataOutputs( |
| RuleContext ruleContext, boolean useUpdatedArgs, List<String> metadataOutputSuffixes) { |
| |
| 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.of(); |
| } |
| ImmutableList.Builder<Artifact> outputs = ImmutableList.<Artifact>builder(); |
| String javaPackage = AndroidCommon.getJavaPackage(ruleContext); |
| for (String suffix : metadataOutputSuffixes) { |
| // The annotation processor automatically creates files with this naming pattern under the |
| // {@code -Aandroid.databinding.generationalFileOutDir} base directory. |
| if (useUpdatedArgs) { |
| outputs.add( |
| getDataBindingArtifact( |
| ruleContext, String.format("%s/%s-%s", METADATA_OUTPUT_DIR, javaPackage, suffix))); |
| } else { |
| outputs.add( |
| getDataBindingArtifact( |
| ruleContext, |
| String.format( |
| "%s/%s-%s-%s", METADATA_OUTPUT_DIR, javaPackage, javaPackage, suffix))); |
| } |
| } |
| return outputs.build(); |
| } |
| |
| @Nullable |
| static Artifact getMetadataOutput( |
| RuleContext ruleContext, boolean useUpdatedArgs, String metadataOutputSuffix) { |
| |
| 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 null; |
| } |
| String javaPackage = AndroidCommon.getJavaPackage(ruleContext); |
| |
| // The annotation processor automatically creates files with this naming pattern under the |
| // {@code -Aandroid.databinding.generationalFileOutDir} base directory. |
| if (useUpdatedArgs) { |
| return getDataBindingArtifact( |
| ruleContext, |
| String.format("%s/%s-%s", METADATA_OUTPUT_DIR, javaPackage, metadataOutputSuffix)); |
| } else { |
| return getDataBindingArtifact( |
| ruleContext, |
| String.format( |
| "%s/%s-%s-%s", METADATA_OUTPUT_DIR, javaPackage, javaPackage, metadataOutputSuffix)); |
| } |
| } |
| |
| /** |
| * Data binding's annotation processor reads the transitive metadata outputs of the target's deps |
| * (see {@link #getMetadataOutputs(RuleContext, List<String>)}) 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 |
| */ |
| 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( |
| SymlinkAction.toArtifact( |
| ruleContext.getActionOwner(), |
| depMetadata, |
| symlink, |
| String.format( |
| "Symlinking dep metadata output %s for %s", depMetadata.getFilename(), ruleLabel))); |
| return symlink; |
| } |
| |
| } |