android/src/com/android/tools/idea/rendering/ClassConverter.java - platform/tools/adt/idea - Git at Google

 /*
  * Copyright (C) 2013 The Android Open Source Project
  *
  * 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.android.tools.idea.rendering;

 import com.android.ide.common.rendering.api.LayoutLog;
 import com.google.common.primitives.Ints;
 import com.google.common.primitives.Shorts;
 import com.intellij.openapi.util.SystemInfo;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.org.objectweb.asm.ClassReader;
 import org.jetbrains.org.objectweb.asm.ClassVisitor;
 import org.jetbrains.org.objectweb.asm.ClassWriter;
 import org.jetbrains.org.objectweb.asm.Label;
 import org.jetbrains.org.objectweb.asm.MethodVisitor;
 import org.jetbrains.org.objectweb.asm.Opcodes;
 import org.jetbrains.org.objectweb.asm.Type;

 import java.util.Collection;

 /**
  * Rewrites classes from one class file version to another and replaces onDraw, onMeasure and onLayout for custom views.
  * <p/>
  * Note that it does not attempt to handle cases where class file constructs cannot
  * be represented in the target version. This is intended for uses such as for example
  * the Android R class, which is simple and can be converted to pretty much any class file
  * version, which makes it possible to load it in an IDE layout render execution context
  * even if it has been compiled for a later version.
  * <p/>
  * For custom views (classes that inherit from android.view.View or any widget in android.widget.*)
  * the onDraw, onMeasure and onLayout methods are replaced with methods that capture any exceptions thrown.
  * This way we avoid custom views breaking the rendering.
  */
 public class ClassConverter {
   private static final String ORIGINAL_SUFFIX = "_Original";
   private static final String ERROR_METHOD_DESCRIPTION;

   static {
     String desc;
     try {
        desc = Type.getMethodDescriptor(LayoutLog.class.getMethod("error", String.class, String.class, Throwable.class, Object.class));
     }
     catch (NoSuchMethodException e) {
       desc = "";
       // We control the API, so the method should always exist.
       assert false;
     }
     ERROR_METHOD_DESCRIPTION = desc;
   }

   /**
    * Rewrites the given class to a version runnable on the current JDK
    */
   @NotNull
   public static byte[] rewriteClass(@NotNull byte[] classData) {
     int current = getCurrentClassVersion();
     return rewriteClass(classData, current, 0);
   }

   /**
    * Rewrites the given class to the given target class file version.
    */
   @NotNull
   public static byte[] rewriteClass(@NotNull byte[] classData, final int maxVersion, final int minVersion) {
     assert maxVersion >= minVersion;

     final ClassWriter classWriter = new ClassWriter(0);
     ClassVisitor classVisitor = new ClassVisitor(Opcodes.ASM5, classWriter) {
       private String myClassName;

       @Override
       public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
         myClassName = name;
         if (version > maxVersion) {
           version = maxVersion;
         }
         if (version < minVersion) {
           version = minVersion;
         }
         super.visit(version, access, name, signature, superName, interfaces);
       }

       /**
        * Creates a new method that calls an existing "name"_Original method and catches any exception the method might throw.
        * The exception is logged via the Bridge logger.
        * <p/>
        * Only void return type methods are currently supported.
        */
       private void wrapMethod(int access, String name, String desc, String signature, String[] exceptions) {
         assert Type.getReturnType(desc) == Type.VOID_TYPE : "Non void return methods are not supported";

         MethodVisitor mw = super.visitMethod(access, name, desc, signature, exceptions);

         Label tryStart = new Label();
         Label tryEnd = new Label();
         Label tryHandler = new Label();
         mw.visitTryCatchBlock(tryStart, tryEnd, tryHandler, "java/lang/Throwable");
         //try{
         mw.visitLabel(tryStart);
         mw.visitVarInsn(Opcodes.ALOAD, 0); // this
         // push all the parameters
         Type[] argumentTypes = Type.getMethodType(desc).getArgumentTypes();
         int nLocals = 1;
         for (Type argType : argumentTypes) {
           mw.visitVarInsn(argType.getOpcode(Opcodes.ILOAD), nLocals++);
         }
         mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, myClassName, name + ORIGINAL_SUFFIX, desc, false);
         mw.visitLabel(tryEnd);
         Label exit = new Label();
         mw.visitJumpInsn(Opcodes.GOTO, exit);
         //} catch(Throwable t) {
         mw.visitLabel(tryHandler);
         mw.visitFrame(Opcodes.F_SAME1, 0, null, 1, new Object[]{"java/lang/Throwable"});
         int throwableIndex = nLocals++;
         mw.visitVarInsn(Opcodes.ASTORE, throwableIndex);

         //  Bridge.getLog().warning()
         mw.visitMethodInsn(Opcodes.INVOKESTATIC, "com/android/layoutlib/bridge/Bridge", "getLog",
                            "()Lcom/android/ide/common/rendering/api/LayoutLog;", false);
         mw.visitLdcInsn(LayoutLog.TAG_BROKEN);
         mw.visitLdcInsn(name + " error");
         mw.visitVarInsn(Opcodes.ALOAD, throwableIndex);
         mw.visitInsn(Opcodes.ACONST_NULL);
         mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "com/android/ide/common/rendering/api/LayoutLog", "error", ERROR_METHOD_DESCRIPTION,
                            false);

         if ("onMeasure".equals(name)) {
           // For onMeasure we need to generate a call to setMeasureDimension to avoid an exception when no size is set
           mw.visitVarInsn(Opcodes.ALOAD, 0); // this
           mw.visitInsn(Opcodes.ICONST_0); // measuredWidth
           mw.visitInsn(Opcodes.ICONST_0); // measuredHeight
           mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, myClassName, "setMeasuredDimension", desc, false);
         }

         mw.visitLabel(exit);
         mw.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
         mw.visitInsn(Opcodes.RETURN);
         mw.visitMaxs(Math.max(argumentTypes.length + 1/*args + this*/, 5/*getLog + getLog parameters*/), nLocals);
       }

       @Override
       public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
         // We catch the exceptions from any onLayout, onMeasure or onDraw that match the signature from the View methods
         if (("onLayout".equals(name) && "(ZIIII)V".equals(desc) ||
              "onMeasure".equals(name) && "(II)V".equals(desc) ||
              "onDraw".equals(name) && "(Landroid/graphics/Canvas;)V".equals(desc)) &&
             ((access & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED)) != 0)) {
           wrapMethod(access, name, desc, signature, exceptions);
           // Make the Original method private so that it does not end up calling the inherited method.
           int modifiedAccess = (access & ~Opcodes.ACC_PUBLIC & ~Opcodes.ACC_PROTECTED) | Opcodes.ACC_PRIVATE;
           return super.visitMethod(modifiedAccess, name + ORIGINAL_SUFFIX, desc, signature, exceptions);
         }

         return super.visitMethod(access, name, desc, signature, exceptions);
       }
     };
     ClassReader reader = new ClassReader(classData);
     reader.accept(classVisitor, 0);
     return classWriter.toByteArray();
   }

   /** Converts a JDK string like 1.6.0_65 to the corresponding class file version number, e.g. 50 */
   public static int jdkToClassVersion(@NotNull String version) { // e.g. 1.6.0_b52
     int dot = version.indexOf('.');
     if (dot != -1) {
       dot++;
       int end = version.length();
       for (int i = dot; i < end; i++) {
         if (!Character.isDigit(version.charAt(i))) {
           end = i;
           break;
         }
       }
       if (end > dot) {
         int major = Integer.valueOf(version.substring(dot, end));
         if (major > 0) {
           return major + 44; // 1.3 => 47, ... 1.6 => 50, 1.7 => 51, ...
         }
       }
     }

     return -1;
   }

   /** Converts a class file version number  JDK string like 1.6.0_65 to the corresponding class file version number, e.g. 50 */
   public static String classVersionToJdk(int version) {
     return "1." + Integer.toString(version - 44); // 47 => 1.3, 50 => 1.6, ...
   }

   /** Given a set of exceptions, return the highest known classfile version format */
   public static int findHighestMajorVersion(Collection<Throwable> list) {
     int result = 0;
     for (Throwable t : list) {
       if (t instanceof InconvertibleClassError) {
         InconvertibleClassError error = (InconvertibleClassError)t;
         result = Math.max(result, error.getMajor());
       }
     }

     return result;
   }

   /** Return the current JDK version number */
   public static String getCurrentJdkVersion() {
     String version = SystemInfo.JAVA_VERSION;
     int suffix = version.indexOf('_');
     if (suffix != -1) {
       version = version.substring(0, suffix);
     }

     return version;
   }

   /** Return the classfile version of the current JDK */
   public static int getCurrentClassVersion() {
     return jdkToClassVersion(SystemInfo.JAVA_VERSION);
   }

   /** Returns true if the given class file data represents a valid class */
   public static boolean isValidClassFile(@NotNull byte[] classData) {
     // See http://en.wikipedia.org/wiki/Java_class_file
     return classData.length >= 7 && getMagic(classData) == 0xCAFEBABE;
   }

   /** Returns the magic number of the given class file */
   public static int getMagic(@NotNull byte[] classData) {
     // See http://en.wikipedia.org/wiki/Java_class_file
     return Ints.fromBytes(classData[0], classData[1], classData[2], classData[3]);
   }

   /** Returns the major class file version */
   public static short getMajorVersion(byte[] classData) {
     // See http://en.wikipedia.org/wiki/Java_class_file
     return Shorts.fromBytes(classData[6], classData[7]);
   }

   /** Returns the minor class file version */
   public static short getMinorVersion(byte[] classData) {
     // See http://en.wikipedia.org/wiki/Java_class_file
     return Shorts.fromBytes(classData[4], classData[5]);
   }
 }
	/*
	* Copyright (C) 2013 The Android Open Source Project
	*
	* 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.android.tools.idea.rendering;

	import com.android.ide.common.rendering.api.LayoutLog;
	import com.google.common.primitives.Ints;
	import com.google.common.primitives.Shorts;
	import com.intellij.openapi.util.SystemInfo;
	import org.jetbrains.annotations.NotNull;
	import org.jetbrains.org.objectweb.asm.ClassReader;
	import org.jetbrains.org.objectweb.asm.ClassVisitor;
	import org.jetbrains.org.objectweb.asm.ClassWriter;
	import org.jetbrains.org.objectweb.asm.Label;
	import org.jetbrains.org.objectweb.asm.MethodVisitor;
	import org.jetbrains.org.objectweb.asm.Opcodes;
	import org.jetbrains.org.objectweb.asm.Type;

	import java.util.Collection;

	/**
	* Rewrites classes from one class file version to another and replaces onDraw, onMeasure and onLayout for custom views.
	* <p/>
	* Note that it does not attempt to handle cases where class file constructs cannot
	* be represented in the target version. This is intended for uses such as for example
	* the Android R class, which is simple and can be converted to pretty much any class file
	* version, which makes it possible to load it in an IDE layout render execution context
	* even if it has been compiled for a later version.
	* <p/>
	* For custom views (classes that inherit from android.view.View or any widget in android.widget.*)
	* the onDraw, onMeasure and onLayout methods are replaced with methods that capture any exceptions thrown.
	* This way we avoid custom views breaking the rendering.
	*/
	public class ClassConverter {
	private static final String ORIGINAL_SUFFIX = "_Original";
	private static final String ERROR_METHOD_DESCRIPTION;

	static {
	String desc;
	try {
	desc = Type.getMethodDescriptor(LayoutLog.class.getMethod("error", String.class, String.class, Throwable.class, Object.class));
	}
	catch (NoSuchMethodException e) {
	desc = "";
	// We control the API, so the method should always exist.
	assert false;
	}
	ERROR_METHOD_DESCRIPTION = desc;
	}

	/**
	* Rewrites the given class to a version runnable on the current JDK
	*/
	@NotNull
	public static byte[] rewriteClass(@NotNull byte[] classData) {
	int current = getCurrentClassVersion();
	return rewriteClass(classData, current, 0);
	}

	/**
	* Rewrites the given class to the given target class file version.
	*/
	@NotNull
	public static byte[] rewriteClass(@NotNull byte[] classData, final int maxVersion, final int minVersion) {
	assert maxVersion >= minVersion;

	final ClassWriter classWriter = new ClassWriter(0);
	ClassVisitor classVisitor = new ClassVisitor(Opcodes.ASM5, classWriter) {
	private String myClassName;

	@Override
	public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
	myClassName = name;
	if (version > maxVersion) {
	version = maxVersion;
	}
	if (version < minVersion) {
	version = minVersion;
	}
	super.visit(version, access, name, signature, superName, interfaces);
	}

	/**
	* Creates a new method that calls an existing "name"_Original method and catches any exception the method might throw.
	* The exception is logged via the Bridge logger.
	* <p/>
	* Only void return type methods are currently supported.
	*/
	private void wrapMethod(int access, String name, String desc, String signature, String[] exceptions) {
	assert Type.getReturnType(desc) == Type.VOID_TYPE : "Non void return methods are not supported";

	MethodVisitor mw = super.visitMethod(access, name, desc, signature, exceptions);

	Label tryStart = new Label();
	Label tryEnd = new Label();
	Label tryHandler = new Label();
	mw.visitTryCatchBlock(tryStart, tryEnd, tryHandler, "java/lang/Throwable");
	//try{
	mw.visitLabel(tryStart);
	mw.visitVarInsn(Opcodes.ALOAD, 0); // this
	// push all the parameters
	Type[] argumentTypes = Type.getMethodType(desc).getArgumentTypes();
	int nLocals = 1;
	for (Type argType : argumentTypes) {
	mw.visitVarInsn(argType.getOpcode(Opcodes.ILOAD), nLocals++);
	}
	mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, myClassName, name + ORIGINAL_SUFFIX, desc, false);
	mw.visitLabel(tryEnd);
	Label exit = new Label();
	mw.visitJumpInsn(Opcodes.GOTO, exit);
	//} catch(Throwable t) {
	mw.visitLabel(tryHandler);
	mw.visitFrame(Opcodes.F_SAME1, 0, null, 1, new Object[]{"java/lang/Throwable"});
	int throwableIndex = nLocals++;
	mw.visitVarInsn(Opcodes.ASTORE, throwableIndex);

	// Bridge.getLog().warning()
	mw.visitMethodInsn(Opcodes.INVOKESTATIC, "com/android/layoutlib/bridge/Bridge", "getLog",
	"()Lcom/android/ide/common/rendering/api/LayoutLog;", false);
	mw.visitLdcInsn(LayoutLog.TAG_BROKEN);
	mw.visitLdcInsn(name + " error");
	mw.visitVarInsn(Opcodes.ALOAD, throwableIndex);
	mw.visitInsn(Opcodes.ACONST_NULL);
	mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "com/android/ide/common/rendering/api/LayoutLog", "error", ERROR_METHOD_DESCRIPTION,
	false);

	if ("onMeasure".equals(name)) {
	// For onMeasure we need to generate a call to setMeasureDimension to avoid an exception when no size is set
	mw.visitVarInsn(Opcodes.ALOAD, 0); // this
	mw.visitInsn(Opcodes.ICONST_0); // measuredWidth
	mw.visitInsn(Opcodes.ICONST_0); // measuredHeight
	mw.visitMethodInsn(Opcodes.INVOKEVIRTUAL, myClassName, "setMeasuredDimension", desc, false);
	}

	mw.visitLabel(exit);
	mw.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
	mw.visitInsn(Opcodes.RETURN);
	mw.visitMaxs(Math.max(argumentTypes.length + 1/args + this/, 5/getLog + getLog parameters/), nLocals);
	}

	@Override
	public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	// We catch the exceptions from any onLayout, onMeasure or onDraw that match the signature from the View methods
	if (("onLayout".equals(name) && "(ZIIII)V".equals(desc) \|\|
	"onMeasure".equals(name) && "(II)V".equals(desc) \|\|
	"onDraw".equals(name) && "(Landroid/graphics/Canvas;)V".equals(desc)) &&
	((access & (Opcodes.ACC_PUBLIC \| Opcodes.ACC_PROTECTED)) != 0)) {
	wrapMethod(access, name, desc, signature, exceptions);
	// Make the Original method private so that it does not end up calling the inherited method.
	int modifiedAccess = (access & ~Opcodes.ACC_PUBLIC & ~Opcodes.ACC_PROTECTED) \| Opcodes.ACC_PRIVATE;
	return super.visitMethod(modifiedAccess, name + ORIGINAL_SUFFIX, desc, signature, exceptions);
	}

	return super.visitMethod(access, name, desc, signature, exceptions);
	}
	};
	ClassReader reader = new ClassReader(classData);
	reader.accept(classVisitor, 0);
	return classWriter.toByteArray();
	}

	/** Converts a JDK string like 1.6.0_65 to the corresponding class file version number, e.g. 50 */
	public static int jdkToClassVersion(@NotNull String version) { // e.g. 1.6.0_b52
	int dot = version.indexOf('.');
	if (dot != -1) {
	dot++;
	int end = version.length();
	for (int i = dot; i < end; i++) {
	if (!Character.isDigit(version.charAt(i))) {
	end = i;
	break;
	}
	}
	if (end > dot) {
	int major = Integer.valueOf(version.substring(dot, end));
	if (major > 0) {
	return major + 44; // 1.3 => 47, ... 1.6 => 50, 1.7 => 51, ...
	}
	}
	}

	return -1;
	}

	/** Converts a class file version number JDK string like 1.6.0_65 to the corresponding class file version number, e.g. 50 */
	public static String classVersionToJdk(int version) {
	return "1." + Integer.toString(version - 44); // 47 => 1.3, 50 => 1.6, ...
	}

	/** Given a set of exceptions, return the highest known classfile version format */
	public static int findHighestMajorVersion(Collection<Throwable> list) {
	int result = 0;
	for (Throwable t : list) {
	if (t instanceof InconvertibleClassError) {
	InconvertibleClassError error = (InconvertibleClassError)t;
	result = Math.max(result, error.getMajor());
	}
	}

	return result;
	}

	/** Return the current JDK version number */
	public static String getCurrentJdkVersion() {
	String version = SystemInfo.JAVA_VERSION;
	int suffix = version.indexOf('_');
	if (suffix != -1) {
	version = version.substring(0, suffix);
	}

	return version;
	}

	/** Return the classfile version of the current JDK */
	public static int getCurrentClassVersion() {
	return jdkToClassVersion(SystemInfo.JAVA_VERSION);
	}

	/** Returns true if the given class file data represents a valid class */
	public static boolean isValidClassFile(@NotNull byte[] classData) {
	// See http://en.wikipedia.org/wiki/Java_class_file
	return classData.length >= 7 && getMagic(classData) == 0xCAFEBABE;
	}

	/** Returns the magic number of the given class file */
	public static int getMagic(@NotNull byte[] classData) {
	// See http://en.wikipedia.org/wiki/Java_class_file
	return Ints.fromBytes(classData[0], classData[1], classData[2], classData[3]);
	}

	/** Returns the major class file version */
	public static short getMajorVersion(byte[] classData) {
	// See http://en.wikipedia.org/wiki/Java_class_file
	return Shorts.fromBytes(classData[6], classData[7]);
	}

	/** Returns the minor class file version */
	public static short getMinorVersion(byte[] classData) {
	// See http://en.wikipedia.org/wiki/Java_class_file
	return Shorts.fromBytes(classData[4], classData[5]);
	}
	}