Add support for exported_deps for aar & jar prebuilts. (#836)

To make generated buck files small and less verbose we can use `exported_deps` for api dependencies. deps of prebuilts are exported by default (i.e dependees of a prebuilt will also get prebuilt's dependencies in it's compile classpath). 

To enable this make the below changes in okbuck extension:
```
okbuck {
    externalDependencies {
        resolutionAction = "latest"
        enableExportedDeps = true
    }
}
```

Note: this only works when `resolutionAction` is either `latest` or `single`.


example generated buck files:
```
// in .okbuck/ext/androidx/activity/BUCK
load('//.okbuck/defs:okbuck_prebuilt.bzl', 'okbuck_prebuilt')

okbuck_prebuilt(
    name = 'activity.aar',
    maven_coords = 'androidx.activity:activity:aar:1.0.0-alpha04',
    sha256 = '4a2c0a2e53933075fa6979b8921a8c7047ec60d5e3906d774f77bd598842aad9',
    sources_sha256 = '6127d87d0d7402172341c6c30591fdb05f7c1e63ec29e79be88d1f8fe46ca762',
    deps = [
        '//3rdparty/jvm/androidx/annotation:annotation.jar',
        '//3rdparty/jvm/androidx/core:core.aar',
        '//3rdparty/jvm/androidx/lifecycle:lifecycle-runtime.aar',
        '//3rdparty/jvm/androidx/lifecycle:lifecycle-viewmodel.aar',
        '//3rdparty/jvm/androidx/savedstate:savedstate-bundle.aar',
    ],
)


// in .okbuck/ext/androidx/lifecycle/BUCK
load('//.okbuck/defs:okbuck_prebuilt.bzl', 'okbuck_prebuilt')

okbuck_prebuilt(
    name = 'lifecycle-runtime.aar',
    maven_coords = 'androidx.lifecycle:lifecycle-runtime:aar:2.0.0',
    sha256 = 'e4afc9e636183f6f3e0edf1cf46121a492ffd2c673075bb07f55c7a99dd43cfb',
    sources_sha256 = '472d99cf093b3b65d24a5707138ce51b160eb81a0ed59095ca8c8e0883ab1524',
    deps = [
        '//3rdparty/jvm/androidx/annotation:annotation.jar',
        '//3rdparty/jvm/androidx/arch/core:core-common.jar',
        '//3rdparty/jvm/androidx/lifecycle:lifecycle-common.jar',
    ],
)

// in an android library buck file
android_library (
    name = 'src_release',
    deps = [
         '//.okbuck/ext/androidx/activity:activity.aar'
    ]
```

In the above android_library we don't need to specify `lifecycle-runtime.aar` or `lifecycle-common.jar` as a dependency since that would be coming transitively. 

To enable this change, make sure you have pulled in facebook/buck#2247 PR on the buck side.

buildSrc/src/main/java/com/uber/okbuck/composer/android/AndroidBuckRuleComposer.java

@@ -3,6 +3,9 @@
 import com.uber.okbuck.composer.jvm.JvmBuckRuleComposer;
 import com.uber.okbuck.core.model.android.AndroidAppTarget;
 import com.uber.okbuck.core.model.android.AndroidTarget;
+import com.uber.okbuck.core.model.base.Target;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 public abstract class AndroidBuckRuleComposer extends JvmBuckRuleComposer {
 
@@ -53,4 +56,12 @@ public static String instrumentation(AndroidAppTarget target) {
   static String instrumentationTest(AndroidAppTarget target) {
     return "instrumentation_" + target.getName() + "_test";
   }
+
+  static Set<String> resources(Set<Target> targets) {
+    return targets
+        .stream()
+        .filter(targetDep -> targetDep instanceof AndroidTarget)
+        .map(targetDep -> resRule((AndroidTarget) targetDep))
+        .collect(Collectors.toSet());
+  }
 }

buildSrc/src/main/java/com/uber/okbuck/composer/android/AndroidLibraryRuleComposer.java

@@ -3,7 +3,6 @@
 import com.google.common.collect.ImmutableSet;
 import com.uber.okbuck.composer.base.BuckRuleComposer;
 import com.uber.okbuck.core.model.android.AndroidLibTarget;
-import com.uber.okbuck.core.model.android.AndroidTarget;
 import com.uber.okbuck.core.model.base.RuleType;
 import com.uber.okbuck.core.model.jvm.JvmTarget;
 import com.uber.okbuck.core.util.D8Util;
@@ -34,13 +33,8 @@ public static Rule compose(
     Set<String> libraryDeps = new HashSet<>(deps);
     libraryDeps.addAll(external(target.getExternalDeps(false)));
     libraryDeps.addAll(targets(target.getTargetDeps(false)));
-    libraryDeps.addAll(
-        target
-            .getTargetDeps(false)
-            .stream()
-            .filter(targetDep -> targetDep instanceof AndroidTarget)
-            .map(targetDep -> resRule((AndroidTarget) targetDep))
-            .collect(Collectors.toSet()));
+    libraryDeps.addAll(resources(target.getTargetDeps(false)));
+    libraryDeps.addAll(resources(target.getTargetExportedDeps(false)));
 
     List<String> libraryAptDeps = new ArrayList<>();
     libraryAptDeps.addAll(externalApt(target.getExternalAptDeps(false)));
@@ -54,6 +48,7 @@ public static Rule compose(
     Set<String> libraryExportedDeps = new HashSet<>();
     libraryExportedDeps.addAll(external(target.getExternalExportedDeps(false)));
     libraryExportedDeps.addAll(targets(target.getTargetExportedDeps(false)));
+    libraryExportedDeps.addAll(aidlRuleNames);
 
     List<String> testTargets = new ArrayList<>();
     if (target.getRobolectricEnabled() && !target.getTest().getSources().isEmpty()) {
@@ -80,7 +75,6 @@ public static Rule compose(
             .sourceCompatibility(target.getSourceCompatibility())
             .targetCompatibility(target.getTargetCompatibility())
             .testTargets(testTargets)
-            .exportedDeps(aidlRuleNames)
             .excludes(appClass != null ? ImmutableSet.of(appClass) : ImmutableSet.of())
             .generateR2(target.getGenerateR2())
             .options(target.getMain().getCustomOptions());

buildSrc/src/main/java/com/uber/okbuck/composer/android/AndroidResourceRuleComposer.java

@@ -4,10 +4,9 @@
 import com.uber.okbuck.core.model.base.RuleType;
 import com.uber.okbuck.template.android.ResourceRule;
 import com.uber.okbuck.template.core.Rule;
-import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
-import java.util.stream.Collectors;
+import java.util.Set;
 
 public final class AndroidResourceRuleComposer extends AndroidBuckRuleComposer {
 
@@ -16,24 +15,22 @@ private AndroidResourceRuleComposer() {
   }
 
   public static Rule compose(AndroidTarget target, List<String> extraResDeps) {
-    List<String> resDeps = new ArrayList<>();
-    resDeps.addAll(external(new HashSet<>(target.getMain().getExternalAarDeps())));
-    resDeps.addAll(
-        target
-            .getTargetDeps(false)
-            .stream()
-            .filter(targetDep -> targetDep instanceof AndroidTarget)
-            .map(targetDep -> resRule((AndroidTarget) targetDep))
-            .collect(Collectors.toSet()));
-
+    Set<String> resDeps = new HashSet<>();
+    resDeps.addAll(external(target.getExternalAarDeps(false)));
+    resDeps.addAll(resources(target.getTargetDeps(false)));
     resDeps.addAll(extraResDeps);
 
+    Set<String> resExportedDeps = new HashSet<>();
+    resExportedDeps.addAll(external(target.getExternalExportedAarDeps(false)));
+    resExportedDeps.addAll(resources(target.getTargetExportedDeps(false)));
+
     return new ResourceRule()
         .pkg(target.getResPackage())
         .res(target.getResDirs())
         .projectRes(target.getProjectResDir())
         .assets(target.getAssetDirs())
         .resourceUnion(target.getOkbuck().useResourceUnion())
+        .exportedDeps(resExportedDeps)
         .defaultVisibility()
         .ruleType(RuleType.ANDROID_RESOURCE.getBuckName())
         .deps(resDeps)

buildSrc/src/main/java/com/uber/okbuck/composer/android/ExopackageAndroidLibraryRuleComposer.java

@@ -31,8 +31,9 @@ public static Rule compose(AndroidAppTarget target) {
     deps.add(":" + buildConfig(target));
 
     Set<String> libraryAptDeps = new LinkedHashSet<>();
-    libraryAptDeps.addAll(externalApt(target.getApt().getExternalJarDeps()));
-    libraryAptDeps.addAll(targetsApt(target.getApt().getTargetDeps()));
+
+    libraryAptDeps.addAll(externalApt(target.getExternalAptDeps(false)));
+    libraryAptDeps.addAll(targetsApt(target.getTargetAptDeps(false)));
 
     Set<String> providedDeps = new LinkedHashSet<>();
     providedDeps.add(D8Util.RT_STUB_JAR_RULE);

buildSrc/src/main/java/com/uber/okbuck/composer/java/JavaAnnotationProcessorRuleComposer.java

@@ -1,5 +1,7 @@
 package com.uber.okbuck.composer.java;
 
+import static com.uber.okbuck.core.dependency.ExternalDependency.filterJar;
+
 import com.google.common.collect.ImmutableSet;
 import com.uber.okbuck.composer.jvm.JvmBuckRuleComposer;
 import com.uber.okbuck.core.model.base.RuleType;
@@ -33,7 +35,7 @@ public static List<Rule> compose(Collection<Scope> scopeList) {
         .map(
             scope -> {
               ImmutableSet.Builder<String> depsBuilder = new ImmutableSet.Builder<>();
-              depsBuilder.addAll(externalApt(scope.getExternalJarDeps()));
+              depsBuilder.addAll(externalApt(filterJar(scope.getExternalDeps())));
               depsBuilder.addAll(targetsApt(scope.getTargetDeps()));
 
               return new JavaAnnotationProcessorRule()

buildSrc/src/main/java/com/uber/okbuck/composer/java/LocalPrebuiltRuleComposer.java

@@ -3,7 +3,6 @@
 import static com.uber.okbuck.core.dependency.BaseExternalDependency.AAR;
 import static com.uber.okbuck.core.dependency.BaseExternalDependency.JAR;
 
-import com.google.common.collect.ImmutableList;
 import com.uber.okbuck.composer.jvm.JvmBuckRuleComposer;
 import com.uber.okbuck.core.dependency.ExternalDependency;
 import com.uber.okbuck.core.model.base.RuleType;
@@ -45,20 +44,16 @@ public static List<Rule> compose(Collection<ExternalDependency> dependencies) {
                 source = null;
               }
 
-              ImmutableList.Builder<Rule> rulesBuilder = ImmutableList.builder();
-              rulesBuilder.add(
-                  new NativePrebuilt()
-                      .prebuiltType(ruleType.getProperties().get(0))
-                      .prebuilt(dependency.getDependencyFileName())
-                      .mavenCoords(dependency.getMavenCoords())
-                      .enableJetifier(dependency.enableJetifier())
-                      .source(source)
-                      .ruleType(ruleType.getBuckName())
-                      .name(dependency.getTargetName()));
-
-              return rulesBuilder.build();
+              return new NativePrebuilt()
+                  .prebuiltType(ruleType.getProperties().get(0))
+                  .prebuilt(dependency.getDependencyFileName())
+                  .mavenCoords(dependency.getMavenCoords())
+                  .enableJetifier(dependency.enableJetifier())
+                  .source(source)
+                  .ruleType(ruleType.getBuckName())
+                  .deps(dependency.getDeps())
+                  .name(dependency.getTargetName());
             })
-        .flatMap(Collection::stream)
         .collect(Collectors.toList());
   }
 }

buildSrc/src/main/java/com/uber/okbuck/composer/java/PrebuiltRuleComposer.java

@@ -45,8 +45,10 @@ public static List<Rule> compose(Collection<ExternalDependency> dependencies) {
                   .getRealSourceFile()
                   .ifPresent(file -> rule.sourcesSha256(DependencyUtils.shaSum256(file)));
 
-              rule.name(dependency.getTargetName());
-              rule.ruleType(RuleType.PREBUILT.getBuckName());
+              rule.ruleType(RuleType.PREBUILT.getBuckName())
+                  .deps(external(dependency.getDeps()))
+                  .name(dependency.getTargetName());
+
               return rule;
             })
         .collect(Collectors.toList());

buildSrc/src/main/java/com/uber/okbuck/core/dependency/DependencyCache.java

@@ -1,17 +1,15 @@
 package com.uber.okbuck.core.dependency;
 
+import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableSet;
 import com.uber.okbuck.core.manager.DependencyManager;
-import com.uber.okbuck.core.model.base.Scope;
 import com.uber.okbuck.core.util.ProjectUtil;
 import com.uber.okbuck.extension.ExternalDependenciesExtension;
 import com.uber.okbuck.extension.JetifierExtension;
 import com.uber.okbuck.extension.OkBuckExtension;
 import java.io.File;
 import java.io.IOException;
 import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -23,6 +21,7 @@
 import org.apache.commons.io.IOUtils;
 import org.gradle.api.Project;
 import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.artifacts.DependencySet;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -44,13 +43,9 @@ public DependencyCache(
     this.skipPrebuilt = skipPrebuilt;
 
     if (forcedConfiguration != null) {
-      Scope.builder(project)
-          .configuration(forcedConfiguration)
-          .build()
-          .getAllExternal()
+      build(forcedConfiguration)
           .forEach(
               dependency -> {
-                get(dependency);
                 forcedDeps.put(dependency.getVersionless(), dependency);
               });
     }
@@ -81,6 +76,16 @@ public final ExternalDependency get(ExternalDependency externalDependency) {
     return dependency;
   }
 
+  public final void addDependencies(DependencySet dependencySet) {
+    this.dependencyManager.addDependencies(
+        dependencySet
+            .stream()
+            .filter(dependency -> dependency instanceof org.gradle.api.artifacts.ExternalDependency)
+            .filter(dependency -> dependency.getGroup() != null && dependency.getVersion() != null)
+            .map(dependency -> (org.gradle.api.artifacts.ExternalDependency) dependency)
+            .collect(Collectors.toSet()));
+  }
+
   /**
    * Get the list of annotation processor classes provided by a dependency.
    *
@@ -90,7 +95,6 @@ public final ExternalDependency get(ExternalDependency externalDependency) {
   public Set<String> getAnnotationProcessors(ExternalDependency externalDependency) {
     ExternalDependency dependency =
         forcedDeps.getOrDefault(externalDependency.getVersionless(), externalDependency);
-    String key = dependency.getTargetName();
 
     try {
       String processors =
@@ -148,32 +152,34 @@ private static String getJarFileContent(File dependencyFile, String filePathStri
     return content;
   }
 
-  public Set<ExternalDependency> build(Configuration configuration) {
-    return build(Collections.singleton(configuration));
-  }
-
   /**
    * Use this method to populate dependency caches of tools/languages etc. This is not meant to be
    * used across multiple threads/gradle task executions which can run in parallel. This method is
    * fully synchronous.
    *
-   * @param configurations The set of configurations to materialize into the dependency cache
+   * @param configuration The configuration to materialize into the dependency cache
    */
-  private Set<ExternalDependency> build(Set<Configuration> configurations) {
+  public Set<ExternalDependency> build(Configuration configuration) {
     OkBuckExtension okBuckExtension = ProjectUtil.getOkBuckExtension(rootProject);
 
     ExternalDependenciesExtension externalDependenciesExtension =
         okBuckExtension.getExternalDependenciesExtension();
     JetifierExtension jetifierExtension = okBuckExtension.getJetifierExtension();
 
-    return configurations
+    addDependencies(configuration.getAllDependencies());
+
+    return DependencyUtils.resolveExternal(
+            rootProject, configuration, externalDependenciesExtension, jetifierExtension)
         .stream()
-        .map(
-            configuration ->
-                DependencyUtils.resolveExternal(
-                    rootProject, configuration, externalDependenciesExtension, jetifierExtension))
-        .flatMap(Collection::stream)
         .map(this::get)
         .collect(Collectors.toSet());
   }
+
+  private Set<ExternalDependency> build(String configuration) {
+    Configuration useful = DependencyUtils.useful(configuration, rootProject);
+
+    Preconditions.checkNotNull(useful);
+
+    return build(useful);
+  }
 }

buildSrc/src/main/java/com/uber/okbuck/core/dependency/DependencyFactory.java

@@ -3,13 +3,18 @@
 import com.uber.okbuck.extension.ExternalDependenciesExtension;
 import com.uber.okbuck.extension.JetifierExtension;
 import java.io.File;
+import java.util.HashSet;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 import org.apache.commons.io.FilenameUtils;
-import org.gradle.api.artifacts.Dependency;
+import org.gradle.api.artifacts.ResolvedDependency;
 
 public final class DependencyFactory {
 
-  private static final String LOCAL_GROUP = "local";
+  public static final String LOCAL_GROUP = "local";
+
   private static final String LOCAL_DEP_VERSION = "1.0.0-LOCAL";
 
   private DependencyFactory() {}
@@ -84,24 +89,58 @@ public static LocalExternalDependency fromLocal(
   }
 
   /**
-   * Returns a versionless dependency from the given gradle dependency.
+   * Returns a set of versionless dependencies from the given gradle dependency.
    *
    * @param dependency gradle dependency
    * @return VersionlessDependency object
    */
-  public static VersionlessDependency fromDependency(Dependency dependency) {
-    VersionlessDependency.Builder vDependency =
+  public static Set<VersionlessDependency> fromDependency(
+      org.gradle.api.artifacts.ExternalDependency dependency) {
+    VersionlessDependency.Builder vDependencyBuilder =
         VersionlessDependency.builder().setName(dependency.getName());
 
     String group = dependency.getGroup();
     if (group == null) {
-      vDependency.setGroup(LOCAL_GROUP);
+      vDependencyBuilder.setGroup(LOCAL_GROUP);
     } else {
-      vDependency.setGroup(group);
+      vDependencyBuilder.setGroup(group);
     }
 
-    // TODO: Add support of specifying classifier
-    return vDependency.build();
+    if (dependency.getArtifacts().size() > 0) {
+      return dependency
+          .getArtifacts()
+          .stream()
+          .map(
+              dependencyArtifact ->
+                  vDependencyBuilder
+                      .setClassifier(Optional.ofNullable(dependencyArtifact.getClassifier()))
+                      .build())
+          .collect(Collectors.toSet());
+    } else {
+      Set<VersionlessDependency> dependencies = new HashSet<>();
+      dependencies.add(vDependencyBuilder.build());
+      return dependencies;
+    }
+  }
+
+  /**
+   * Returns a set of versionless dependency from the given gradle resolved dependency.
+   *
+   * @param dependency gradle dependency
+   * @return VersionlessDependency object
+   */
+  public static Set<VersionlessDependency> fromDependency(ResolvedDependency dependency) {
+    return dependency
+        .getModuleArtifacts()
+        .stream()
+        .map(
+            resolvedArtifact ->
+                VersionlessDependency.builder()
+                    .setName(dependency.getModuleName())
+                    .setGroup(dependency.getModuleGroup())
+                    .setClassifier(Optional.ofNullable(resolvedArtifact.getClassifier()))
+                    .build())
+        .collect(Collectors.toSet());
   }
 
   /**