Add support library fragment watcher (#1611)

* watch leaking support library fragments and their views

* add support-fragments to leakcnacary-core, remove duplicated code for fragment watcher creation

build.gradle

@@ -24,6 +24,7 @@ buildscript {
               runner  : 'androidx.test:runner:1.1.0',
           ],
       ],
+      android_support: 'com.android.support:support-v4:28.0.0',
       junit         : 'junit:junit:4.12',
       kotlin        : [
           gradlePlugin: "org.jetbrains.kotlin:kotlin-gradle-plugin:${versions.kotlin}",
@@ -42,7 +43,7 @@ buildscript {
   }
   dependencies {
     classpath deps.kotlin.gradlePlugin
-    classpath 'com.android.tools.build:gradle:3.5.0'
+    classpath 'com.android.tools.build:gradle:3.5.2'
     classpath 'net.ltgt.gradle:gradle-errorprone-plugin:0.0.16'
     classpath 'com.github.ben-manes:gradle-versions-plugin:0.20.0'
     classpath "org.jetbrains.dokka:dokka-gradle-plugin:0.9.18"

leakcanary-android-core/build.gradle

@@ -5,6 +5,7 @@ dependencies {
   api project(':shark-android')
   api project(':leakcanary-object-watcher-android')
   api project(':leakcanary-object-watcher-android-androidx')
+  api project(':leakcanary-object-watcher-android-support-fragments')
 
   implementation deps.kotlin.stdlib
 

leakcanary-object-watcher-android-support-fragments/build.gradle

@@ -0,0 +1,25 @@
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+dependencies {
+  api project(':leakcanary-object-watcher-android')
+
+  implementation deps.kotlin.stdlib
+  // Optional dependency
+  compileOnly deps.android_support
+}
+
+android {
+  compileSdkVersion versions.compileSdk
+  defaultConfig {
+    minSdkVersion versions.minSdk
+    consumerProguardFiles 'consumer-proguard-rules.pro'
+  }
+  lintOptions {
+    disable 'GoogleAppIndexingWarning'
+    error 'ObsoleteSdkInt'
+    check 'Interoperability'
+  }
+}
+
+apply from: rootProject.file('gradle/gradle-mvn-push.gradle')

leakcanary-object-watcher-android-support-fragments/consumer-proguard-rules.pro

@@ -0,0 +1,2 @@
+# AndroidSupportFragmentDestroyWatcher is loaded via reflection
+-keep class leakcanary.internal.AndroidSupportFragmentDestroyWatcher { *; }

leakcanary-object-watcher-android-support-fragments/gradle.properties

@@ -0,0 +1,3 @@
+POM_ARTIFACT_ID=leakcanary-object-watcher-android-support-fragments
+POM_NAME=LeakCanary Object Watcher for Android extension: Android support library fragments support
+POM_PACKAGING=aar

leakcanary-object-watcher-android-support-fragments/src/main/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.squareup.leakcanary.fragments.android_support" />

leakcanary-object-watcher-android-support-fragments/src/main/java/leakcanary/internal/AndroidSupportFragmentDestroyWatcher.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2019 Square, Inc.
+ *
+ * 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 leakcanary.internal
+
+import android.app.Activity
+import android.support.v4.app.Fragment
+import android.support.v4.app.FragmentActivity
+import android.support.v4.app.FragmentManager
+import leakcanary.AppWatcher.Config
+import leakcanary.ObjectWatcher
+
+internal class AndroidSupportFragmentDestroyWatcher(
+  private val objectWatcher: ObjectWatcher,
+  private val configProvider: () -> Config
+) : (Activity) -> Unit {
+
+  private val fragmentLifecycleCallbacks = object : FragmentManager.FragmentLifecycleCallbacks() {
+
+    override fun onFragmentViewDestroyed(
+      fm: FragmentManager,
+      fragment: Fragment
+    ) {
+      val view = fragment.view
+      if (view != null && configProvider().watchFragmentViews) {
+        objectWatcher.watch(view)
+      }
+    }
+
+    override fun onFragmentDestroyed(
+      fm: FragmentManager,
+      fragment: Fragment
+    ) {
+      if (configProvider().watchFragments) {
+        objectWatcher.watch(fragment)
+      }
+    }
+  }
+
+  override fun invoke(activity: Activity) {
+    if (activity is FragmentActivity) {
+      val supportFragmentManager = activity.supportFragmentManager
+      supportFragmentManager.registerFragmentLifecycleCallbacks(fragmentLifecycleCallbacks, true)
+    }
+  }
+}

leakcanary-object-watcher-android/src/main/java/leakcanary/internal/FragmentDestroyWatcher.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2018 Square, Inc.
+ * Copyright (C) 2019 Square, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,10 @@ internal object FragmentDestroyWatcher {
   private const val ANDROIDX_FRAGMENT_DESTROY_WATCHER_CLASS_NAME =
     "leakcanary.internal.AndroidXFragmentDestroyWatcher"
 
+  private const val ANDROID_SUPPORT_FRAGMENT_CLASS_NAME = "android.support.v4.app.Fragment"
+  private const val ANDROID_SUPPORT_FRAGMENT_DESTROY_WATCHER_CLASS_NAME =
+    "leakcanary.internal.AndroidSupportFragmentDestroyWatcher"
+
   fun install(
     application: Application,
     objectWatcher: ObjectWatcher,
@@ -46,15 +50,22 @@ internal object FragmentDestroyWatcher {
       )
     }
 
-    if (classAvailable(ANDROIDX_FRAGMENT_CLASS_NAME) &&
-        classAvailable(ANDROIDX_FRAGMENT_DESTROY_WATCHER_CLASS_NAME)
-    ) {
-      val watcherConstructor = Class.forName(ANDROIDX_FRAGMENT_DESTROY_WATCHER_CLASS_NAME)
-          .getDeclaredConstructor(ObjectWatcher::class.java, Function0::class.java)
-      @kotlin.Suppress("UNCHECKED_CAST")
-      fragmentDestroyWatchers.add(
-          watcherConstructor.newInstance(objectWatcher, configProvider) as (Activity) -> Unit
-      )
+    getWatcherIfAvailable(
+        ANDROIDX_FRAGMENT_CLASS_NAME,
+        ANDROIDX_FRAGMENT_DESTROY_WATCHER_CLASS_NAME,
+        objectWatcher,
+        configProvider
+    )?.let {
+      fragmentDestroyWatchers.add(it)
+    }
+
+    getWatcherIfAvailable(
+        ANDROID_SUPPORT_FRAGMENT_CLASS_NAME,
+        ANDROID_SUPPORT_FRAGMENT_DESTROY_WATCHER_CLASS_NAME,
+        objectWatcher,
+        configProvider
+    )?.let {
+      fragmentDestroyWatchers.add(it)
     }
 
     if (fragmentDestroyWatchers.size == 0) {
@@ -73,6 +84,26 @@ internal object FragmentDestroyWatcher {
     })
   }
 
+  private fun getWatcherIfAvailable(
+    fragmentClassName: String,
+    watcherClassName: String,
+    objectWatcher: ObjectWatcher,
+    configProvider: () -> AppWatcher.Config
+  ): ((Activity) -> Unit)? {
+
+    return if (classAvailable(fragmentClassName) &&
+            classAvailable(watcherClassName)
+    ) {
+      val watcherConstructor = Class.forName(watcherClassName)
+              .getDeclaredConstructor(ObjectWatcher::class.java, Function0::class.java)
+      @Suppress("UNCHECKED_CAST")
+      watcherConstructor.newInstance(objectWatcher, configProvider) as (Activity) -> Unit
+
+    } else {
+      null
+    }
+  }
+
   private fun classAvailable(className: String): Boolean {
     return try {
       Class.forName(className)

settings.gradle

@@ -6,6 +6,7 @@ include ':leakcanary-android-sample'
 include ':leakcanary-object-watcher'
 include ':leakcanary-object-watcher-android'
 include ':leakcanary-object-watcher-android-androidx'
+include ':leakcanary-object-watcher-android-support-fragments'
 include ':shark'
 include ':shark-android'
 include ':shark-cli'