Introduce gif rewriter stub

app/src/main/cpp/CMakeLists.txt

@@ -45,6 +45,6 @@ SET(LIBARCHIVE_CUSTOM_LIBS "liblzma" "nettle")
 add_subdirectory(libarchive)
 
 # Build and link our app's native lib
-add_library(${PROJECT_NAME} SHARED archive.c fdutils.c)
+add_library(${PROJECT_NAME} SHARED archive.c fdutils.c gifutils.c)
 target_include_directories(${PROJECT_NAME} PUBLIC libarchive/libarchive)
 target_link_libraries(${PROJECT_NAME} archive_static log -Wl,--gc-sections)

app/src/main/cpp/gifutils.c

@@ -0,0 +1,15 @@
+#include <jni.h>
+
+#include <android/log.h>
+
+#define LOG_TAG "gifUtils"
+
+#include "ehviewer.h"
+
+JNIEXPORT void JNICALL
+Java_com_hippo_image_Image_rewriteGifSource(JNIEnv *env, jclass clazz, jobject buffer) {
+    void *addr = (*env)->GetDirectBufferAddress(env, buffer);
+    size_t size = (*env)->GetDirectBufferCapacity(env, buffer);
+    EH_UNUSED(addr);
+    EH_UNUSED(size);
+}

app/src/main/java/com/hippo/image/Image.kt

@@ -80,6 +80,7 @@ class Image private constructor(source: Source, private var releaseCall: (() ->
         fun decode(src: ByteBufferSource): Image? {
             val directBuffer = src.getByteBuffer()
             check(directBuffer.isDirect)
+            rewriteGifSource(directBuffer)
             return runCatching {
                 Image(ImageDecoder.createSource(directBuffer)) {
                     src.close()
@@ -89,6 +90,9 @@ class Image private constructor(source: Source, private var releaseCall: (() ->
                 it.printStackTrace()
             }.getOrNull()
         }
+
+        @JvmStatic
+        private external fun rewriteGifSource(buffer: ByteBuffer)
     }
 
     interface ByteBufferSource : AutoCloseable {