Add LiveData Transformation

chao2zhang · Apr 6, 2021 · ca29bed · ca29bed
1 parent 39cc830
commit ca29bed
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Showing 5 changed files with 118 additions and 7 deletions.
diff --git a/build.gradle b/build.gradle
@@ -6,9 +6,13 @@ plugins {
 }
 
 repositories {
-    mavenCentral()
     google()
-    jcenter()
+    mavenCentral()
+    jcenter {
+        content {
+            includeGroup "org.jetbrains.trove4j"
+        }
+    }
 }
 
 gradlePlugin {
@@ -26,7 +30,16 @@ compileJava {
 }
 
 dependencies {
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.4.31"
+    constraints {
+        implementation("org.jetbrains.kotlin:kotlin-reflect:1.4.31") {
+            because("Android Gradle Plugin 4.1 depends on Kotlin 1.3.72 but we should not mix 1.3 and 1.4.")
+        }
+        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.4.31") {
+            because("Android Gradle Plugin 4.1 depends on Kotlin 1.3.72 but we should not mix 1.3 and 1.4.")
+        }
+    }
     implementation 'com.android.tools.build:gradle-api:4.1.3'
+    implementation 'org.ow2.asm:asm:9.1'
     compileOnly 'com.android.tools.build:gradle:4.1.3'
 }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0-milestone-3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/src/main/kotlin/io/github/chao2zhang/LoggingLiveDataClassVisitor.kt b/src/main/kotlin/io/github/chao2zhang/LoggingLiveDataClassVisitor.kt
@@ -0,0 +1,25 @@
+package io.github.chao2zhang
+
+import org.objectweb.asm.ClassVisitor
+import org.objectweb.asm.MethodVisitor
+import org.objectweb.asm.Opcodes.ASM9
+
+class LoggingLiveDataClassVisitor(
+    private val classVisitor: ClassVisitor
+) : ClassVisitor(ASM9, classVisitor) {
+
+    override fun visitMethod(
+        access: Int,
+        name: String?,
+        descriptor: String?,
+        signature: String?,
+        exceptions: Array<out String>?
+    ): MethodVisitor {
+        val methodVisitor = classVisitor.visitMethod(access, name, descriptor, signature, exceptions)
+        return if (name == "considerNotify") {
+            LoggingLiveDataMethodVisitor(methodVisitor)
+        } else {
+            methodVisitor
+        }
+    }
+}
diff --git a/src/main/kotlin/io/github/chao2zhang/LoggingLiveDataMethodVisitor.kt b/src/main/kotlin/io/github/chao2zhang/LoggingLiveDataMethodVisitor.kt
@@ -0,0 +1,54 @@
+package io.github.chao2zhang
+
+import org.objectweb.asm.MethodVisitor
+import org.objectweb.asm.Opcodes
+import org.objectweb.asm.Opcodes.ASM9
+
+/**
+ * Add the following code after invoking `observer.onChanged`:
+ * ```
+ *     Log.i("LiveData", "considerNotify() called with LiveData = " + this + " Observer = " + observer.mObserver + " Data = " + this.mData);
+ * ```
+ */
+class LoggingLiveDataMethodVisitor(
+    private val methodVisitor: MethodVisitor
+) : MethodVisitor(ASM9, methodVisitor) {
+
+    override fun visitMethodInsn(
+        opcode: Int,
+        owner: String?,
+        name: String?,
+        descriptor: String?,
+        isInterface: Boolean
+    ) {
+        methodVisitor.visitMethodInsn(opcode, owner, name, descriptor, isInterface)
+        if (opcode == Opcodes.INVOKEINTERFACE && owner == "androidx/lifecycle/Observer" && name == "onChanged") {
+            methodVisitor.visitLdcInsn("LiveData")
+            methodVisitor.visitTypeInsn(Opcodes.NEW, "java/lang/StringBuilder")
+            methodVisitor.visitInsn(Opcodes.DUP)
+            methodVisitor.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "()V", false)
+            methodVisitor.visitLdcInsn("considerNotify() called with LiveData = ")
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false)
+            methodVisitor.visitVarInsn(Opcodes.ALOAD, 0)
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/Object;)Ljava/lang/StringBuilder;", false)
+            methodVisitor.visitLdcInsn(" Observer = ")
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false)
+            methodVisitor.visitVarInsn(Opcodes.ALOAD, 1)
+            methodVisitor.visitFieldInsn(Opcodes.GETFIELD, "androidx/lifecycle/LiveData\$ObserverWrapper", "mObserver", "Landroidx/lifecycle/Observer;")
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/Object;)Ljava/lang/StringBuilder;", false)
+            methodVisitor.visitLdcInsn(" Data = ")
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false)
+            methodVisitor.visitVarInsn(Opcodes.ALOAD, 0)
+            methodVisitor.visitFieldInsn(Opcodes.GETFIELD, "androidx/lifecycle/LiveData", "mData", "Ljava/lang/Object;")
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/Object;)Ljava/lang/StringBuilder;", false)
+            methodVisitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;", false)
+            methodVisitor.visitMethodInsn(Opcodes.INVOKESTATIC, "android/util/Log", "i", "(Ljava/lang/String;Ljava/lang/String;)I", false)
+            methodVisitor.visitInsn(Opcodes.POP)
+        }
+    }
+
+
+    override fun visitMaxs(maxStack: Int, maxLocals: Int) {
+        methodVisitor.visitMaxs(3, 2)
+    }
+}
diff --git a/src/main/kotlin/io/github/chao2zhang/LoggingLiveDataTransform.kt b/src/main/kotlin/io/github/chao2zhang/LoggingLiveDataTransform.kt
@@ -9,9 +9,14 @@ import com.android.build.api.transform.TransformInput
 import com.android.build.api.transform.TransformInvocation
 import com.android.build.api.variant.VariantInfo
 import org.gradle.api.logging.Logger
+import org.objectweb.asm.ClassReader
+import org.objectweb.asm.ClassWriter
+import org.objectweb.asm.util.TraceClassVisitor
 import java.io.BufferedOutputStream
 import java.io.File
 import java.io.FileOutputStream
+import java.io.PrintWriter
+import java.io.StringWriter
 import java.util.zip.ZipEntry
 import java.util.zip.ZipFile
 import java.util.zip.ZipOutputStream
@@ -47,7 +52,6 @@ class LoggingLiveDataTransform(private val logger: Logger) : Transform() {
                 jarInput.scopes,
                 Format.JAR
             )
-            logger.lifecycle("Transforming ${jarInput.file}")
             if (transformInvocation.isIncremental) {
                 when (jarInput.status) {
                     Status.ADDED, Status.CHANGED -> transformJarInput(jarInput, inputJar, outputJar)
@@ -74,10 +78,22 @@ class LoggingLiveDataTransform(private val logger: Logger) : Transform() {
         val inputEntries = inputZip.entries()
         while (inputEntries.hasMoreElements()) {
             val inputEntry = inputEntries.nextElement()
+            val inputBytes = inputZip.getInputStream(inputEntry).readAllBytes()
+            var outputBytes = inputBytes
+            if (inputEntry.isLiveDataClass()) {
+                logger.lifecycle("Transforming $inputEntry to add logging statements in LiveData")
+                val stringWriter = StringWriter()
+                val classReader = ClassReader(inputBytes)
+                val classWriter = ClassWriter(classReader, 0)
+                val tracingClassVisitor = TraceClassVisitor(classWriter, PrintWriter(stringWriter))
+                val classVisitor = LoggingLiveDataClassVisitor(tracingClassVisitor)
+                classReader.accept(classVisitor, 0)
+                outputBytes = classWriter.toByteArray()
+            }
             val outputEntry = ZipEntry(inputEntry.name)
             with(outputZip) {
                 putNextEntry(outputEntry)
-                write(inputZip.getInputStream(inputEntry).readAllBytes())
+                write(outputBytes)
                 closeEntry()
             }
         }
@@ -86,5 +102,8 @@ class LoggingLiveDataTransform(private val logger: Logger) : Transform() {
     }
 
     private fun JarInput.isLiveDataJarInput(): Boolean =
-        name.startsWith("androidx.lifecycle:lifecycle-livedata:")
+        name.startsWith("androidx.lifecycle:lifecycle-livedata-core:")
+
+    private fun ZipEntry.isLiveDataClass(): Boolean =
+        name == "androidx/lifecycle/LiveData.class"
 }