1 files changed, 334 insertions, 0 deletions
diff --git a/libs/hwui/jni/ByteBufferStreamAdaptor.cpp b/libs/hwui/jni/ByteBufferStreamAdaptor.cpp
new file mode 100644
index 000000000000..db5f6f6c684f
--- /dev/null
+++ b/libs/hwui/jni/ByteBufferStreamAdaptor.cpp
@@ -0,0 +1,334 @@
+#include "ByteBufferStreamAdaptor.h"
+#include "GraphicsJNI.h"
+#include "Utils.h"
+
+#include <SkStream.h>
+
+using namespace android;
+
+static jmethodID gByteBuffer_getMethodID;
+static jmethodID gByteBuffer_setPositionMethodID;
+
+/**
+ * Helper method for accessing the JNI interface pointer.
+ *
+ * Image decoding (which this supports) is started on a thread that is already
+ * attached to the Java VM. But an AnimatedImageDrawable continues decoding on
+ * the AnimatedImageThread, which is not attached. This will attach if
+ * necessary.
+ */
+static JNIEnv* requireEnv(JavaVM* jvm) {
+    JNIEnv* env;
+    if (jvm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
+        if (jvm->AttachCurrentThreadAsDaemon(&env, nullptr) != JNI_OK) {
+            LOG_ALWAYS_FATAL("Failed to AttachCurrentThread!");
+        }
+    }
+    return env;
+}
+
+class ByteBufferStream : public SkStreamAsset {
+private:
+    ByteBufferStream(JavaVM* jvm, jobject jbyteBuffer, size_t initialPosition, size_t length,
+                     jbyteArray storage)
+            : mJvm(jvm)
+            , mByteBuffer(jbyteBuffer)
+            , mPosition(0)
+            , mInitialPosition(initialPosition)
+            , mLength(length)
+            , mStorage(storage) {}
+
+public:
+    static ByteBufferStream* Create(JavaVM* jvm, JNIEnv* env, jobject jbyteBuffer,
+                                    size_t position, size_t length) {
+        // This object outlives its native method call.
+        jbyteBuffer = env->NewGlobalRef(jbyteBuffer);
+        if (!jbyteBuffer) {
+            return nullptr;
+        }
+
+        jbyteArray storage = env->NewByteArray(kStorageSize);
+        if (!storage) {
+            env->DeleteGlobalRef(jbyteBuffer);
+            return nullptr;
+        }
+
+        // This object outlives its native method call.
+        storage = static_cast<jbyteArray>(env->NewGlobalRef(storage));
+        if (!storage) {
+            env->DeleteGlobalRef(jbyteBuffer);
+            return nullptr;
+        }
+
+        return new ByteBufferStream(jvm, jbyteBuffer, position, length, storage);
+    }
+
+    ~ByteBufferStream() override {
+        auto* env = requireEnv(mJvm);
+        env->DeleteGlobalRef(mByteBuffer);
+        env->DeleteGlobalRef(mStorage);
+    }
+
+    size_t read(void* buffer, size_t size) override {
+        if (size > mLength - mPosition) {
+            size = mLength - mPosition;
+        }
+        if (!size) {
+            return 0;
+        }
+
+        if (!buffer) {
+            return this->setPosition(mPosition + size) ? size : 0;
+        }
+
+        auto* env = requireEnv(mJvm);
+        size_t bytesRead = 0;
+        do {
+            const size_t requested = (size > kStorageSize) ? kStorageSize : size;
+            const jint jrequested = static_cast<jint>(requested);
+            env->CallObjectMethod(mByteBuffer, gByteBuffer_getMethodID, mStorage, 0, jrequested);
+            if (env->ExceptionCheck()) {
+                ALOGE("Error in ByteBufferStream::read - was the ByteBuffer modified externally?");
+                env->ExceptionDescribe();
+                env->ExceptionClear();
+                mPosition = mLength;
+                return bytesRead;
+            }
+
+            env->GetByteArrayRegion(mStorage, 0, requested, reinterpret_cast<jbyte*>(buffer));
+            if (env->ExceptionCheck()) {
+                ALOGE("Internal error in ByteBufferStream::read");
+                env->ExceptionDescribe();
+                env->ExceptionClear();
+                mPosition = mLength;
+                return bytesRead;
+            }
+
+            mPosition += requested;
+            buffer = reinterpret_cast<void*>(reinterpret_cast<char*>(buffer) + requested);
+            bytesRead += requested;
+            size -= requested;
+        } while (size);
+        return bytesRead;
+    }
+
+    bool isAtEnd() const override { return mLength == mPosition; }
+
+    // SkStreamRewindable overrides
+    bool rewind() override { return this->setPosition(0); }
+
+    SkStreamAsset* onDuplicate() const override {
+        // SkStreamRewindable requires overriding this, but it is not called by
+        // decoders, so does not need a true implementation. A proper
+        // implementation would require duplicating the ByteBuffer, which has
+        // its own internal position state.
+        return nullptr;
+    }
+
+    // SkStreamSeekable overrides
+    size_t getPosition() const override { return mPosition; }
+
+    bool seek(size_t position) override {
+        return this->setPosition(position > mLength ? mLength : position);
+    }
+
+    bool move(long offset) override {
+        long newPosition = mPosition + offset;
+        if (newPosition < 0) {
+            return this->setPosition(0);
+        }
+        return this->seek(static_cast<size_t>(newPosition));
+    }
+
+    SkStreamAsset* onFork() const override {
+        // SkStreamSeekable requires overriding this, but it is not called by
+        // decoders, so does not need a true implementation. A proper
+        // implementation would require duplicating the ByteBuffer, which has
+        // its own internal position state.
+        return nullptr;
+    }
+
+    // SkStreamAsset overrides
+    size_t getLength() const override { return mLength; }
+
+private:
+    JavaVM*          mJvm;
+    jobject          mByteBuffer;
+    // Logical position of the SkStream, between 0 and mLength.
+    size_t           mPosition;
+    // Initial position of mByteBuffer, treated as mPosition 0.
+    const size_t     mInitialPosition;
+    // Logical length of the SkStream, from mInitialPosition to
+    // mByteBuffer.limit().
+    const size_t     mLength;
+
+    // Range has already been checked by the caller.
+    bool setPosition(size_t newPosition) {
+        auto* env = requireEnv(mJvm);
+        env->CallObjectMethod(mByteBuffer, gByteBuffer_setPositionMethodID,
+                              newPosition + mInitialPosition);
+        if (env->ExceptionCheck()) {
+            ALOGE("Internal error in ByteBufferStream::setPosition");
+            env->ExceptionDescribe();
+            env->ExceptionClear();
+            mPosition = mLength;
+            return false;
+        }
+        mPosition = newPosition;
+        return true;
+    }
+
+    // FIXME: This is an arbitrary storage size, which should be plenty for
+    // some formats (png, gif, many bmps). But for jpeg, the more we can supply
+    // in one call the better, and webp really wants all of the data. How to
+    // best choose the amount of storage used?
+    static constexpr size_t kStorageSize = 4096;
+    jbyteArray mStorage;
+};
+
+class ByteArrayStream : public SkStreamAsset {
+private:
+    ByteArrayStream(JavaVM* jvm, jbyteArray jarray, size_t offset, size_t length)
+            : mJvm(jvm), mByteArray(jarray), mOffset(offset), mPosition(0), mLength(length) {}
+
+public:
+    static ByteArrayStream* Create(JavaVM* jvm, JNIEnv* env, jbyteArray jarray, size_t offset,
+                                   size_t length) {
+        // This object outlives its native method call.
+        jarray = static_cast<jbyteArray>(env->NewGlobalRef(jarray));
+        if (!jarray) {
+            return nullptr;
+        }
+        return new ByteArrayStream(jvm, jarray, offset, length);
+    }
+
+    ~ByteArrayStream() override {
+        auto* env = requireEnv(mJvm);
+        env->DeleteGlobalRef(mByteArray);
+    }
+
+    size_t read(void* buffer, size_t size) override {
+        if (size > mLength - mPosition) {
+            size = mLength - mPosition;
+        }
+        if (!size) {
+            return 0;
+        }
+
+        auto* env = requireEnv(mJvm);
+        if (buffer) {
+            env->GetByteArrayRegion(mByteArray, mPosition + mOffset, size,
+                                    reinterpret_cast<jbyte*>(buffer));
+            if (env->ExceptionCheck()) {
+                ALOGE("Internal error in ByteArrayStream::read");
+                env->ExceptionDescribe();
+                env->ExceptionClear();
+                mPosition = mLength;
+                return 0;
+            }
+        }
+
+        mPosition += size;
+        return size;
+    }
+
+    bool isAtEnd() const override { return mLength == mPosition; }
+
+    // SkStreamRewindable overrides
+    bool rewind() override {
+        mPosition = 0;
+        return true;
+    }
+    SkStreamAsset* onDuplicate() const override {
+        // SkStreamRewindable requires overriding this, but it is not called by
+        // decoders, so does not need a true implementation. Note that a proper
+        // implementation is fairly straightforward
+        return nullptr;
+    }
+
+    // SkStreamSeekable overrides
+    size_t getPosition() const override { return mPosition; }
+
+    bool seek(size_t position) override {
+        mPosition = (position > mLength) ? mLength : position;
+        return true;
+    }
+
+    bool move(long offset) override {
+        long newPosition = mPosition + offset;
+        if (newPosition < 0) {
+            return this->seek(0);
+        }
+        return this->seek(static_cast<size_t>(newPosition));
+    }
+
+    SkStreamAsset* onFork() const override {
+        // SkStreamSeekable requires overriding this, but it is not called by
+        // decoders, so does not need a true implementation. Note that a proper
+        // implementation is fairly straightforward
+        return nullptr;
+    }
+
+    // SkStreamAsset overrides
+    size_t getLength() const override { return mLength; }
+
+private:
+    JavaVM*      mJvm;
+    jbyteArray   mByteArray;
+    // Offset in mByteArray. Only used when communicating with Java.
+    const size_t mOffset;
+    // Logical position of the SkStream, between 0 and mLength.
+    size_t       mPosition;
+    const size_t mLength;
+};
+
+struct release_proc_context {
+    JavaVM* jvm;
+    jobject jbyteBuffer;
+};
+
+std::unique_ptr<SkStream> CreateByteBufferStreamAdaptor(JNIEnv* env, jobject jbyteBuffer,
+                                                        size_t position, size_t limit) {
+    JavaVM* jvm;
+    LOG_ALWAYS_FATAL_IF(env->GetJavaVM(&jvm) != JNI_OK);
+
+    const size_t length = limit - position;
+    void* addr = env->GetDirectBufferAddress(jbyteBuffer);
+    if (addr) {
+        addr = reinterpret_cast<void*>(reinterpret_cast<char*>(addr) + position);
+        jbyteBuffer = env->NewGlobalRef(jbyteBuffer);
+        if (!jbyteBuffer) {
+            return nullptr;
+        }
+
+        auto* context = new release_proc_context{jvm, jbyteBuffer};
+        auto releaseProc = [](const void*, void* context) {
+            auto* c = reinterpret_cast<release_proc_context*>(context);
+            JNIEnv* env = get_env_or_die(c->jvm);
+            env->DeleteGlobalRef(c->jbyteBuffer);
+            delete c;
+        };
+        auto data = SkData::MakeWithProc(addr, length, releaseProc, context);
+        // The new SkMemoryStream will read directly from addr.
+        return std::unique_ptr<SkStream>(new SkMemoryStream(std::move(data)));
+    }
+
+    // Non-direct, or direct access is not supported.
+    return std::unique_ptr<SkStream>(ByteBufferStream::Create(jvm, env, jbyteBuffer, position,
+                                                              length));
+}
+
+std::unique_ptr<SkStream> CreateByteArrayStreamAdaptor(JNIEnv* env, jbyteArray array, size_t offset,
+                                                       size_t length) {
+    JavaVM* jvm;
+    LOG_ALWAYS_FATAL_IF(env->GetJavaVM(&jvm) != JNI_OK);
+
+    return std::unique_ptr<SkStream>(ByteArrayStream::Create(jvm, env, array, offset, length));
+}
+
+int register_android_graphics_ByteBufferStreamAdaptor(JNIEnv* env) {
+    jclass byteBuffer_class = FindClassOrDie(env, "java/nio/ByteBuffer");
+    gByteBuffer_getMethodID         = GetMethodIDOrDie(env, byteBuffer_class, "get", "([BII)Ljava/nio/ByteBuffer;");
+    gByteBuffer_setPositionMethodID = GetMethodIDOrDie(env, byteBuffer_class, "position", "(I)Ljava/nio/Buffer;");
+    return true;
+}