The Tor Browser: build/annotationProcessors/CodeGenerator.java@97036ab72558 (annotated)

build/annotationProcessors/CodeGenerator.java@97036ab72558 (annotated)

build/annotationProcessors/CodeGenerator.java

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 package org.mozilla.gecko.annotationProcessors;
 import org.mozilla.gecko.annotationProcessors.classloader.AnnotatableEntity;
 import org.mozilla.gecko.annotationProcessors.utils.Utils;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.Member;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.HashMap;
 import java.util.HashSet;
 public class CodeGenerator {
     private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
     private static final Annotation[][] GETTER_ARGUMENT_ANNOTATIONS = new Annotation[0][0];
     private static final Annotation[][] SETTER_ARGUMENT_ANNOTATIONS = new Annotation[1][0];
     // Buffers holding the strings to ultimately be written to the output files.
     private final StringBuilder zeroingCode = new StringBuilder();
     private final StringBuilder wrapperStartupCode = new StringBuilder();
     private final StringBuilder wrapperMethodBodies = new StringBuilder();
     private final StringBuilder headerPublic = new StringBuilder();
     private final StringBuilder headerProtected = new StringBuilder();
     private final HashSet<String> seenClasses = new HashSet<String>();
     private final String mCClassName;
     private final Class<?> mClassToWrap;
     private boolean mHasEncounteredDefaultConstructor;
     // Used for creating unique names for method ID fields in the face of
     private final HashMap<Member, String> mMembersToIds = new HashMap<Member, String>();
     private final HashSet<String> mTakenMemberNames = new HashSet<String>();
     private int mNameMunger;
     public CodeGenerator(Class<?> aClass, String aGeneratedName) {
         mClassToWrap = aClass;
         mCClassName = aGeneratedName;
         // Write the file header things. Includes and so forth.
         // GeneratedJNIWrappers.cpp is generated as the concatenation of wrapperStartupCode with
         // wrapperMethodBodies. Similarly, GeneratedJNIWrappers.h is the concatenation of headerPublic
         // with headerProtected.
         wrapperStartupCode.append("void ").append(mCClassName).append("::InitStubs(JNIEnv *jEnv) {\n" +
                                   "    initInit();\n");
         // Now we write the various GetStaticMethodID calls here...
         headerPublic.append("class ").append(mCClassName).append(" : public AutoGlobalWrappedJavaObject {\n" +
                             "public:\n" +
                             "    static void InitStubs(JNIEnv *jEnv);\n");
         headerProtected.append("protected:");
         generateWrapperMethod();
     }
     /**
      * Emit a static method which takes an instance of the class being wrapped and returns an instance
      * of the C++ wrapper class backed by that object.
      */
     private void generateWrapperMethod() {
         headerPublic.append("    static ").append(mCClassName).append("* Wrap(jobject obj);\n" +
                 "    ").append(mCClassName).append("(jobject obj, JNIEnv* env) : AutoGlobalWrappedJavaObject(obj, env) {};\n");
         wrapperMethodBodies.append("\n").append(mCClassName).append("* ").append(mCClassName).append("::Wrap(jobject obj) {\n" +
                 "    JNIEnv *env = GetJNIForThread();\n" +
                 "    ").append(mCClassName).append("* ret = new ").append(mCClassName).append("(obj, env);\n" +
                 "    env->DeleteLocalRef(obj);\n" +
                 "    return ret;\n" +
                 "}\n");
     }
     private void generateMemberCommon(Member theMethod, String aCMethodName, Class<?> aClass) {
         ensureClassHeaderAndStartup(aClass);
         writeMemberIdField(theMethod, aCMethodName);
         writeStartupCode(theMethod);
     }
     /**
      * Append the appropriate generated code to the buffers for the method provided.
      *
      * @param aMethodTuple The Java method, plus annotation data.
      */
     public void generateMethod(AnnotatableEntity aMethodTuple) {
         // Unpack the tuple and extract some useful fields from the Method..
         Method theMethod = aMethodTuple.getMethod();
         String CMethodName = aMethodTuple.mAnnotationInfo.wrapperName;
         generateMemberCommon(theMethod, CMethodName, mClassToWrap);
         boolean isFieldStatic = Utils.isMemberStatic(theMethod);
         boolean shallGenerateStatic = isFieldStatic || aMethodTuple.mAnnotationInfo.isStatic;
         Class<?>[] parameterTypes = theMethod.getParameterTypes();
         Class<?> returnType = theMethod.getReturnType();
         // Get the C++ method signature for this method.
         String implementationSignature = Utils.getCImplementationMethodSignature(parameterTypes, returnType, CMethodName, mCClassName);
         String headerSignature = Utils.getCHeaderMethodSignature(parameterTypes, theMethod.getParameterAnnotations(), returnType, CMethodName, mCClassName, shallGenerateStatic);
         // Add the header signature to the header file.
         writeSignatureToHeader(headerSignature);
         // Use the implementation signature to generate the method body...
         writeMethodBody(implementationSignature, CMethodName, theMethod, mClassToWrap,
             aMethodTuple.mAnnotationInfo.isStatic,
             aMethodTuple.mAnnotationInfo.isMultithreaded,
             aMethodTuple.mAnnotationInfo.noThrow);
     }
     private void generateGetterOrSetterBody(Class<?> aFieldType, String aFieldName, boolean aIsFieldStatic, boolean isSetter) {
         StringBuilder argumentContent = null;
         if (isSetter) {
             Class<?>[] setterArguments = new Class<?>[]{aFieldType};
             // Marshall the argument..
             argumentContent = getArgumentMarshalling(setterArguments);
         }
         boolean isObjectReturningMethod = Utils.isObjectType(aFieldType);
         wrapperMethodBodies.append("    ");
         if (isSetter) {
             wrapperMethodBodies.append("env->Set");
         } else {
             wrapperMethodBodies.append("return ");
             if (isObjectReturningMethod) {
                 wrapperMethodBodies.append("static_cast<").append(Utils.getCReturnType(aFieldType)).append(">(");
             }
             wrapperMethodBodies.append("env->Get");
         }
         if (aIsFieldStatic) {
             wrapperMethodBodies.append("Static");
         }
         wrapperMethodBodies.append(Utils.getFieldType(aFieldType))
                            .append("Field(");
         // Static will require the class and the field id. Nonstatic, the object and the field id.
         if (aIsFieldStatic) {
             wrapperMethodBodies.append(Utils.getClassReferenceName(mClassToWrap));
         } else {
             wrapperMethodBodies.append("wrapped_obj");
         }
         wrapperMethodBodies.append(", j")
                            .append(aFieldName);
         if (isSetter) {
             wrapperMethodBodies.append(argumentContent);
         }
         if (!isSetter && isObjectReturningMethod) {
             wrapperMethodBodies.append(')');
         }
         wrapperMethodBodies.append(");\n" +
                                "}\n");
     }
     public void generateField(AnnotatableEntity aFieldTuple) {
         Field theField = aFieldTuple.getField();
         // Handles a peculiar case when dealing with enum types. We don't care about this field.
         // It just gets in the way and stops our code from compiling.
         if (theField.getName().equals("$VALUES")) {
             return;
         }
         String CFieldName = aFieldTuple.mAnnotationInfo.wrapperName;
         Class<?> fieldType = theField.getType();
         generateMemberCommon(theField, CFieldName, mClassToWrap);
         boolean isFieldStatic = Utils.isMemberStatic(theField);
         boolean isFieldFinal = Utils.isMemberFinal(theField);
         boolean shallGenerateStatic = isFieldStatic || aFieldTuple.mAnnotationInfo.isStatic;
         String getterName = "get" + CFieldName;
         String getterSignature = Utils.getCImplementationMethodSignature(EMPTY_CLASS_ARRAY, fieldType, getterName, mCClassName);
         String getterHeaderSignature = Utils.getCHeaderMethodSignature(EMPTY_CLASS_ARRAY, GETTER_ARGUMENT_ANNOTATIONS, fieldType, getterName, mCClassName, shallGenerateStatic);
         writeSignatureToHeader(getterHeaderSignature);
         writeFunctionStartupBoilerPlate(getterSignature, fieldType, isFieldStatic, true);
         generateGetterOrSetterBody(fieldType, CFieldName, isFieldStatic, false);
         // If field not final, also generate a setter function.
         if (!isFieldFinal) {
             String setterName = "set" + CFieldName;
             Class<?>[] setterArguments = new Class<?>[]{fieldType};
             String setterSignature = Utils.getCImplementationMethodSignature(setterArguments, Void.class, setterName, mCClassName);
             String setterHeaderSignature = Utils.getCHeaderMethodSignature(setterArguments, SETTER_ARGUMENT_ANNOTATIONS, Void.class, setterName, mCClassName, shallGenerateStatic);
             writeSignatureToHeader(setterHeaderSignature);
             writeFunctionStartupBoilerPlate(setterSignature, Void.class, isFieldStatic, true);
             generateGetterOrSetterBody(fieldType, CFieldName, isFieldStatic, true);
         }
     }
     public void generateConstructor(AnnotatableEntity aCtorTuple) {
         // Unpack the tuple and extract some useful fields from the Method..
         Constructor theCtor = aCtorTuple.getConstructor();
         String CMethodName = mCClassName;
         generateMemberCommon(theCtor, mCClassName, mClassToWrap);
         String implementationSignature = Utils.getCImplementationMethodSignature(theCtor.getParameterTypes(), Void.class, CMethodName, mCClassName);
         String headerSignature = Utils.getCHeaderMethodSignature(theCtor.getParameterTypes(), theCtor.getParameterAnnotations(), Void.class, CMethodName, mCClassName, false);
         // Slice off the "void " from the start of the constructor declaration.
         headerSignature = headerSignature.substring(5);
         implementationSignature = implementationSignature.substring(5);
         // Add the header signatures to the header file.
         writeSignatureToHeader(headerSignature);
         // Use the implementation signature to generate the method body...
         writeCtorBody(implementationSignature, theCtor,
             aCtorTuple.mAnnotationInfo.isMultithreaded,
             aCtorTuple.mAnnotationInfo.noThrow);
         if (theCtor.getParameterTypes().length == 0) {
             mHasEncounteredDefaultConstructor = true;
         }
     }
     /**
      * Writes the appropriate header and startup code to ensure the existence of a reference to the
      * class specified. If this is already done, does nothing.
      *
      * @param aClass The target class.
      */
     private void ensureClassHeaderAndStartup(Class<?> aClass) {
         String className = aClass.getCanonicalName();
         if (seenClasses.contains(className)) {
             return;
         }
         zeroingCode.append("jclass ")
                    .append(mCClassName)
                    .append("::")
                    .append(Utils.getClassReferenceName(aClass))
                    .append(" = 0;\n");
         // Add a field to hold the reference...
         headerProtected.append("\n    static jclass ")
                        .append(Utils.getClassReferenceName(aClass))
                        .append(";\n");
         // Add startup code to populate it..
         wrapperStartupCode.append('\n')
                           .append(Utils.getStartupLineForClass(aClass));
         seenClasses.add(className);
     }
     /**
      * Write out the function startup boilerplate for the method described. Check for environment
      * existence,
      * @param methodSignature
      * @param returnType
      * @param aIsStatic
      * @param aIsThreaded
      */
     private void writeFunctionStartupBoilerPlate(String methodSignature, Class<?> returnType, boolean aIsStatic, boolean aIsThreaded) {
         // The start-of-function boilerplate. Does the bridge exist? Does the env exist? etc.
         wrapperMethodBodies.append('\n')
                            .append(methodSignature)
                            .append(" {\n");
         wrapperMethodBodies.append("    JNIEnv *env = ");
         if (!aIsThreaded) {
             wrapperMethodBodies.append("AndroidBridge::GetJNIEnv();\n");
         } else {
             wrapperMethodBodies.append("GetJNIForThread();\n");
         }
     }
     /**
      * Write out the appropriate JNI frame pushing boilerplate for a call to the member provided (
      * which must be a constructor or method).
      *
      * @param aMethod A constructor/method being wrapped.
      * @param aIsObjectReturningMethod Does the method being wrapped return an object?
      */
     private void writeFramePushBoilerplate(Member aMethod,
             boolean aIsObjectReturningMethod, boolean aNoThrow) {
         if (aMethod instanceof Field) {
             throw new IllegalArgumentException("Tried to push frame for a FIELD?!");
         }
         Method m;
         Constructor c;
         Class<?> returnType;
         int localReferencesNeeded;
         if (aMethod instanceof Method) {
             m = (Method) aMethod;
             returnType = m.getReturnType();
             localReferencesNeeded = Utils.enumerateReferenceArguments(m.getParameterTypes());
         } else {
             c = (Constructor) aMethod;
             returnType = Void.class;
             localReferencesNeeded = Utils.enumerateReferenceArguments(c.getParameterTypes());
         }
         // Determine the number of local refs required for our local frame..
         // AutoLocalJNIFrame is not applicable here due to it's inability to handle return values.
         if (aIsObjectReturningMethod) {
             localReferencesNeeded++;
         }
         wrapperMethodBodies.append(
                 "    if (env->PushLocalFrame(").append(localReferencesNeeded).append(") != 0) {\n");
         if (!aNoThrow) {
             wrapperMethodBodies.append(
                 "        AndroidBridge::HandleUncaughtException(env);\n" +
                 "        MOZ_ASSUME_UNREACHABLE(\"Exception should have caused crash.\");\n");
         } else {
             wrapperMethodBodies.append(
                 "        return").append(Utils.getFailureReturnForType(returnType)).append(";\n");
         }
         wrapperMethodBodies.append(
                 "    }\n\n");
     }
     private StringBuilder getArgumentMarshalling(Class<?>[] argumentTypes) {
         StringBuilder argumentContent = new StringBuilder();
         // If we have >2 arguments, use the jvalue[] calling approach.
         argumentContent.append(", ");
         if (argumentTypes.length > 2) {
             wrapperMethodBodies.append("    jvalue args[").append(argumentTypes.length).append("];\n");
             for (int aT = 0; aT < argumentTypes.length; aT++) {
                 wrapperMethodBodies.append("    args[").append(aT).append("].")
                                    .append(Utils.getArrayArgumentMashallingLine(argumentTypes[aT], "a" + aT));
             }
             // The only argument is the array of arguments.
             argumentContent.append("args");
             wrapperMethodBodies.append('\n');
         } else {
             // Otherwise, use the vanilla calling approach.
             boolean needsNewline = false;
             for (int aT = 0; aT < argumentTypes.length; aT++) {
                 // If the argument is a string-esque type, create a jstring from it, otherwise
                 // it can be passed directly.
                 if (Utils.isCharSequence(argumentTypes[aT])) {
                     wrapperMethodBodies.append("    jstring j").append(aT).append(" = AndroidBridge::NewJavaString(env, a").append(aT).append(");\n");
                     needsNewline = true;
                     // Ensure we refer to the newly constructed Java string - not to the original
                     // parameter to the wrapper function.
                     argumentContent.append('j').append(aT);
                 } else {
                     argumentContent.append('a').append(aT);
                 }
                 if (aT != argumentTypes.length - 1) {
                     argumentContent.append(", ");
                 }
             }
             if (needsNewline) {
                 wrapperMethodBodies.append('\n');
             }
         }
         return argumentContent;
     }
     private void writeCtorBody(String implementationSignature, Constructor theCtor,
             boolean aIsThreaded, boolean aNoThrow) {
         Class<?>[] argumentTypes = theCtor.getParameterTypes();
         writeFunctionStartupBoilerPlate(implementationSignature, Void.class, false, aIsThreaded);
         writeFramePushBoilerplate(theCtor, false, aNoThrow);
         // Marshall arguments for this constructor, if any...
         boolean hasArguments = argumentTypes.length != 0;
         StringBuilder argumentContent = new StringBuilder();
         if (hasArguments) {
             argumentContent = getArgumentMarshalling(argumentTypes);
         }
         // The call into Java
         wrapperMethodBodies.append("    Init(env->NewObject");
         if (argumentTypes.length > 2) {
             wrapperMethodBodies.append('A');
         }
         wrapperMethodBodies.append('(');
         // Call takes class id, method id of constructor method, then arguments.
         wrapperMethodBodies.append(Utils.getClassReferenceName(mClassToWrap)).append(", ");
         wrapperMethodBodies.append(mMembersToIds.get(theCtor))
         // Tack on the arguments, if any..
                            .append(argumentContent)
                            .append("), env);\n" +
                                    "    env->PopLocalFrame(nullptr);\n" +
                                    "}\n");
     }
     /**
      * Generates the method body of the C++ wrapper function for the Java method indicated.
      *
      * @param methodSignature The previously-generated C++ method signature for the method to be
      *                        generated.
      * @param aCMethodName    The C++ method name for the method to be generated.
      * @param aMethod         The Java method to be wrapped by the C++ method being generated.
      * @param aClass          The Java class to which the method belongs.
      */
     private void writeMethodBody(String methodSignature, String aCMethodName, Method aMethod,
             Class<?> aClass, boolean aIsStaticBridgeMethod, boolean aIsMultithreaded,
             boolean aNoThrow) {
         Class<?>[] argumentTypes = aMethod.getParameterTypes();
         Class<?> returnType = aMethod.getReturnType();
         writeFunctionStartupBoilerPlate(methodSignature, returnType, aIsStaticBridgeMethod, aIsMultithreaded);
         boolean isObjectReturningMethod = !returnType.getCanonicalName().equals("void") && Utils.isObjectType(returnType);
         writeFramePushBoilerplate(aMethod, isObjectReturningMethod, aNoThrow);
         // Marshall arguments, if we have any.
         boolean hasArguments = argumentTypes.length != 0;
         // We buffer the arguments to the call separately to avoid needing to repeatedly iterate the
         // argument list while building this line. In the coming code block, we simultaneously
         // construct any argument marshalling code (Creation of jstrings, placement of arguments
         // into an argument array, etc. and the actual argument list passed to the function (in
         // argumentContent).
         StringBuilder argumentContent = new StringBuilder();
         if (hasArguments) {
             argumentContent = getArgumentMarshalling(argumentTypes);
         }
         // Allocate a temporary variable to hold the return type from Java.
         wrapperMethodBodies.append("    ");
         if (!returnType.getCanonicalName().equals("void")) {
             if (isObjectReturningMethod) {
                 wrapperMethodBodies.append("jobject");
             } else {
                 wrapperMethodBodies.append(Utils.getCReturnType(returnType));
             }
             wrapperMethodBodies.append(" temp = ");
         }
         boolean isStaticJavaMethod = Utils.isMemberStatic(aMethod);
         // The call into Java
         wrapperMethodBodies.append("env->")
                            .append(Utils.getCallPrefix(returnType, isStaticJavaMethod));
         if (argumentTypes.length > 2) {
             wrapperMethodBodies.append('A');
         }
         wrapperMethodBodies.append('(');
         // If the underlying Java method is nonstatic, we provide the target object to the JNI.
         if (!isStaticJavaMethod) {
             wrapperMethodBodies.append("wrapped_obj, ");
         } else {
             // If this is a static underlying Java method, we need to use the class reference in our
             // call.
             wrapperMethodBodies.append(Utils.getClassReferenceName(aClass)).append(", ");
         }
         wrapperMethodBodies.append(mMembersToIds.get(aMethod));
         // Tack on the arguments, if any..
         wrapperMethodBodies.append(argumentContent)
                            .append(");\n");
         // Check for exception and crash if any...
         if (!aNoThrow) {
             wrapperMethodBodies.append("    AndroidBridge::HandleUncaughtException(env);\n");
         }
         // If we're returning an object, pop the callee's stack frame extracting our ref as the return
         // value.
         if (isObjectReturningMethod) {
             wrapperMethodBodies.append("    ")
                                .append(Utils.getCReturnType(returnType))
                                .append(" ret = static_cast<").append(Utils.getCReturnType(returnType)).append(">(env->PopLocalFrame(temp));\n" +
                                        "    return ret;\n");
         } else if (!returnType.getCanonicalName().equals("void")) {
             // If we're a primitive-returning function, just return the directly-obtained primative
             // from the call to Java.
             wrapperMethodBodies.append("    env->PopLocalFrame(nullptr);\n" +
                                        "    return temp;\n");
         } else {
             // If we don't return anything, just pop the stack frame and move on with life.
             wrapperMethodBodies.append("    env->PopLocalFrame(nullptr);\n");
         }
         wrapperMethodBodies.append("}\n");
     }
     /**
      * Generates the code to get the id of the given member on startup.
      *
      * @param aMember         The Java member being wrapped.
      */
     private void writeStartupCode(Member aMember) {
         wrapperStartupCode.append("    ")
                           .append(mMembersToIds.get(aMember))
                           .append(" = get");
         if (Utils.isMemberStatic(aMember)) {
             wrapperStartupCode.append("Static");
         }
         boolean isField = aMember instanceof Field;
         if (isField) {
             wrapperStartupCode.append("Field(\"");
         } else {
             wrapperStartupCode.append("Method(\"");
         }
         if (aMember instanceof Constructor) {
             wrapperStartupCode.append("<init>");
         } else {
             wrapperStartupCode.append(aMember.getName());
         }
         wrapperStartupCode.append("\", \"")
                           .append(Utils.getTypeSignatureStringForMember(aMember))
                           .append("\");\n");
     }
     private void writeZeroingFor(Member aMember, final String aMemberName) {
         if (aMember instanceof Field) {
             zeroingCode.append("jfieldID ");
         } else {
             zeroingCode.append("jmethodID ");
         }
         zeroingCode.append(mCClassName)
                    .append("::")
                    .append(aMemberName)
                    .append(" = 0;\n");
     }
     /**
      * Write the field declaration for the C++ id field of the given member.
      *
      * @param aMember Member for which an id field needs to be generated.
      */
     private void writeMemberIdField(Member aMember, final String aCMethodName) {
         String memberName = 'j'+ aCMethodName;
         if (aMember instanceof Field) {
             headerProtected.append("    static jfieldID ");
         } else {
             headerProtected.append("    static jmethodID ");
         }
         while(mTakenMemberNames.contains(memberName)) {
             memberName = 'j' + aCMethodName + mNameMunger;
             mNameMunger++;
         }
         writeZeroingFor(aMember, memberName);
         mMembersToIds.put(aMember, memberName);
         mTakenMemberNames.add(memberName);
         headerProtected.append(memberName)
                        .append(";\n");
     }
     /**
      * Helper function to add a provided method signature to the public section of the generated header.
      *
      * @param aSignature The header to add.
      */
     private void writeSignatureToHeader(String aSignature) {
         headerPublic.append("    ")
                     .append(aSignature)
                     .append(";\n");
     }
     /**
      * Get the finalised bytes to go into the generated wrappers file.
      *
      * @return The bytes to be written to the wrappers file.
      */
     public String getWrapperFileContents() {
         wrapperStartupCode.append("}\n");
         zeroingCode.append(wrapperStartupCode)
                    .append(wrapperMethodBodies);
         wrapperMethodBodies.setLength(0);
         wrapperStartupCode.setLength(0);
         return zeroingCode.toString();
     }
     /**
      * Get the finalised bytes to go into the generated header file.
      *
      * @return The bytes to be written to the header file.
      */
     public String getHeaderFileContents() {
         if (!mHasEncounteredDefaultConstructor) {
             headerPublic.append("    ").append(mCClassName).append("() : AutoGlobalWrappedJavaObject() {};\n");
         }
         headerProtected.append("};\n\n");
         headerPublic.append(headerProtected);
         headerProtected.setLength(0);
         return headerPublic.toString();
     }
 }

The Tor Browser / annotate

build/annotationProcessors/CodeGenerator.java@97036ab72558 (annotated)

build/annotationProcessors/CodeGenerator.java