Use UTF-8 strings to avoid duplicate caching, part 1

StringBlock instances containing UTF-8 strings use a cache to convert
into UTF-16, but using that cache and then using a JNI call to NewString
causes the UTF-8 string as well as two copies of the UTF-16 string to
be held in memory. Getting the UTF-8 string directly from the StringPool
eliminates one copy of the UTF-16 string being held in memory.

This is part 1. Part 2 will include ResXMLParser optimizations.

Change-Id: Ibd4509a485db746d59cd4b9501f544877139276c

1 files changed, 5 insertions, 0 deletions

diff --git a/core/jni/android_util_StringBlock.cpp b/core/jni/android_util_StringBlock.cpp
index ffb271c..641fbce 100644
--- a/core/jni/android_util_StringBlock.cpp
+++ b/core/jni/android_util_StringBlock.cpp
@@ -89,6 +89,11 @@ static jstring android_content_StringBlock_nativeGetString(JNIEnv* env, jobject
     }
 
     size_t len;
+    const char* str8 = osb->string8At(idx, &len);
+    if (str8 != NULL) {
+        return env->NewStringUTF(str8);
+    }
+
     const char16_t* str = osb->stringAt(idx, &len);
     if (str == NULL) {
         doThrow(env, "java/lang/IndexOutOfBoundsException");