Improve performance when getting styled string.

The style used in the composing text for input methods
takes a long time to create. This is experienced as a
lag when composing the first word.

The bottleneck lies in the 10 calls to
nativeIndexOfString which does a linear search through
thousands of strings.

Change-Id: I3184b2be3673d384cca19e9a70ad94b4d3085576

Author: Peter Eliasson

core/java/android/content/res/StringBlock.java

@@ -87,21 +87,48 @@ public CharSequence get(int idx) {
             if (style != null) {
                 if (mStyleIDs == null) {
                     mStyleIDs = new StyleIDs();
-                    mStyleIDs.boldId = nativeIndexOfString(mNative, "b");
-                    mStyleIDs.italicId = nativeIndexOfString(mNative, "i");
-                    mStyleIDs.underlineId = nativeIndexOfString(mNative, "u");
-                    mStyleIDs.ttId = nativeIndexOfString(mNative, "tt");
-                    mStyleIDs.bigId = nativeIndexOfString(mNative, "big");
-                    mStyleIDs.smallId = nativeIndexOfString(mNative, "small");
-                    mStyleIDs.supId = nativeIndexOfString(mNative, "sup");
-                    mStyleIDs.subId = nativeIndexOfString(mNative, "sub");
-                    mStyleIDs.strikeId = nativeIndexOfString(mNative, "strike");
-                    mStyleIDs.listItemId = nativeIndexOfString(mNative, "li");
-                    mStyleIDs.marqueeId = nativeIndexOfString(mNative, "marquee");
-
-                    if (localLOGV) Log.v(TAG, "BoldId=" + mStyleIDs.boldId
-                            + ", ItalicId=" + mStyleIDs.italicId
-                            + ", UnderlineId=" + mStyleIDs.underlineId);
+                }
+
+                // the style array is a flat array of <type, start, end> hence
+                // the magic constant 3.
+                for (int styleIndex = 0; styleIndex < style.length; styleIndex += 3) {
+                    int styleId = style[styleIndex];
+
+                    if (styleId == mStyleIDs.boldId || styleId == mStyleIDs.italicId
+                            || styleId == mStyleIDs.underlineId || styleId == mStyleIDs.ttId
+                            || styleId == mStyleIDs.bigId || styleId == mStyleIDs.smallId
+                            || styleId == mStyleIDs.subId || styleId == mStyleIDs.supId
+                            || styleId == mStyleIDs.strikeId || styleId == mStyleIDs.listItemId
+                            || styleId == mStyleIDs.marqueeId) {
+                        // id already found skip to next style
+                        continue;
+                    }
+
+                    String styleTag = nativeGetString(mNative, styleId);
+
+                    if (styleTag.equals("b")) {
+                        mStyleIDs.boldId = styleId;
+                    } else if (styleTag.equals("i")) {
+                        mStyleIDs.italicId = styleId;
+                    } else if (styleTag.equals("u")) {
+                        mStyleIDs.underlineId = styleId;
+                    } else if (styleTag.equals("tt")) {
+                        mStyleIDs.ttId = styleId;
+                    } else if (styleTag.equals("big")) {
+                        mStyleIDs.bigId = styleId;
+                    } else if (styleTag.equals("small")) {
+                        mStyleIDs.smallId = styleId;
+                    } else if (styleTag.equals("sup")) {
+                        mStyleIDs.supId = styleId;
+                    } else if (styleTag.equals("sub")) {
+                        mStyleIDs.subId = styleId;
+                    } else if (styleTag.equals("strike")) {
+                        mStyleIDs.strikeId = styleId;
+                    } else if (styleTag.equals("li")) {
+                        mStyleIDs.listItemId = styleId;
+                    } else if (styleTag.equals("marquee")) {
+                        mStyleIDs.marqueeId = styleId;
+                    }
                 }
 
                 res = applyStyles(str, style, mStyleIDs);
@@ -119,17 +146,17 @@ protected void finalize() throws Throwable {
     }
 
     static final class StyleIDs {
-        private int boldId;
-        private int italicId;
-        private int underlineId;
-        private int ttId;
-        private int bigId;
-        private int smallId;
-        private int subId;
-        private int supId;
-        private int strikeId;
-        private int listItemId;
-        private int marqueeId;
+        private int boldId = -1;
+        private int italicId = -1;
+        private int underlineId = -1;
+        private int ttId = -1;
+        private int bigId = -1;
+        private int smallId = -1;
+        private int subId = -1;
+        private int supId = -1;
+        private int strikeId = -1;
+        private int listItemId = -1;
+        private int marqueeId = -1;
     }
 
     private CharSequence applyStyles(String str, int[] style, StyleIDs ids) {
@@ -403,6 +430,5 @@ private static final native int nativeCreate(byte[] data,
     private static final native int nativeGetSize(int obj);
     private static final native String nativeGetString(int obj, int idx);
     private static final native int[] nativeGetStyle(int obj, int idx);
-    private static final native int nativeIndexOfString(int obj, String str);
     private static final native void nativeDestroy(int obj);
 }

core/jni/android_util_StringBlock.cpp

@@ -147,25 +147,6 @@ static jintArray android_content_StringBlock_nativeGetStyle(JNIEnv* env, jobject
     return array;
 }
 
-static jint android_content_StringBlock_nativeIndexOfString(JNIEnv* env, jobject clazz,
-                                                         jint token, jstring str)
-{
-    ResStringPool* osb = (ResStringPool*)token;
-    if (osb == NULL || str == NULL) {
-        doThrow(env, "java/lang/NullPointerException");
-        return 0;
-    }
-
-    const char16_t* str16 = env->GetStringChars(str, NULL);
-    jsize strLen = env->GetStringLength(str);
-
-    ssize_t idx = osb->indexOfString(str16, strLen);
-
-    env->ReleaseStringChars(str, str16);
-
-    return idx;
-}
-
 static void android_content_StringBlock_nativeDestroy(JNIEnv* env, jobject clazz,
                                                    jint token)
 {
@@ -193,8 +174,6 @@ static JNINativeMethod gStringBlockMethods[] = {
             (void*) android_content_StringBlock_nativeGetString },
     { "nativeGetStyle",    "(II)[I",
             (void*) android_content_StringBlock_nativeGetStyle },
-    { "nativeIndexOfString","(ILjava/lang/String;)I",
-            (void*) android_content_StringBlock_nativeIndexOfString },
     { "nativeDestroy",      "(I)V",
             (void*) android_content_StringBlock_nativeDestroy },
 };