From 852cd720590c120f23f033f53540a73ac64c4234 Mon Sep 17 00:00:00 2001
From: Jesse Wilson <jesse@swank.ca>
Date: Sat, 26 Nov 2011 15:36:08 +0000
Subject: [PATCH] Don't allocate a whole bunch of objects each time we
 deserialize a map key. This saves 20% on bug 375's benchmark.

The fix here is quite distasteful; I'm adding an ugly backdoor API for MapTypeAdapterFactory to fiddle with the internal bits of JsonReader. I'd like to revisit this sooner or later, but for now I'll take the speedup.
---
 .../internal/JsonReaderInternalAccess.java    | 32 +++++++++++++++++++
 .../internal/bind/MapTypeAdapterFactory.java  |  5 +--
 .../com/google/gson/stream/JsonReader.java    | 15 +++++++++
 3 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 gson/src/main/java/com/google/gson/internal/JsonReaderInternalAccess.java

diff --git a/gson/src/main/java/com/google/gson/internal/JsonReaderInternalAccess.java b/gson/src/main/java/com/google/gson/internal/JsonReaderInternalAccess.java
new file mode 100644
index 00000000..bbd47204
--- /dev/null
+++ b/gson/src/main/java/com/google/gson/internal/JsonReaderInternalAccess.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gson.internal;
+
+import com.google.gson.stream.JsonReader;
+import java.io.IOException;
+
+/**
+ * Internal-only APIs of JsonReader available only to other classes in Gson.
+ */
+public abstract class JsonReaderInternalAccess {
+  public static JsonReaderInternalAccess INSTANCE;
+
+  /**
+   * Changes the type of the current property name token to a string value.
+   */
+  public abstract void promoteNameToValue(JsonReader reader) throws IOException;
+}
diff --git a/gson/src/main/java/com/google/gson/internal/bind/MapTypeAdapterFactory.java b/gson/src/main/java/com/google/gson/internal/bind/MapTypeAdapterFactory.java
index 5e0da20d..88102474 100644
--- a/gson/src/main/java/com/google/gson/internal/bind/MapTypeAdapterFactory.java
+++ b/gson/src/main/java/com/google/gson/internal/bind/MapTypeAdapterFactory.java
@@ -23,6 +23,7 @@ import com.google.gson.JsonSyntaxException;
 import com.google.gson.TypeAdapter;
 import com.google.gson.internal.$Gson$Types;
 import com.google.gson.internal.ConstructorConstructor;
+import com.google.gson.internal.JsonReaderInternalAccess;
 import com.google.gson.internal.ObjectConstructor;
 import com.google.gson.internal.Streams;
 import com.google.gson.reflect.TypeToken;
@@ -180,8 +181,8 @@ public final class MapTypeAdapterFactory implements TypeAdapter.Factory {
       } else {
         reader.beginObject();
         while (reader.hasNext()) {
-          String keyString = reader.nextName();
-          K key = keyTypeAdapter.fromJsonElement(new JsonPrimitive(keyString));
+          JsonReaderInternalAccess.INSTANCE.promoteNameToValue(reader);
+          K key = keyTypeAdapter.read(reader);
           V value = valueTypeAdapter.read(reader);
           V replaced = map.put(key, value);
           if (replaced != null) {
diff --git a/gson/src/main/java/com/google/gson/stream/JsonReader.java b/gson/src/main/java/com/google/gson/stream/JsonReader.java
index 4f366d0a..9b691397 100644
--- a/gson/src/main/java/com/google/gson/stream/JsonReader.java
+++ b/gson/src/main/java/com/google/gson/stream/JsonReader.java
@@ -16,6 +16,7 @@
 
 package com.google.gson.stream;
 
+import com.google.gson.internal.JsonReaderInternalAccess;
 import java.io.Closeable;
 import java.io.EOFException;
 import java.io.IOException;
@@ -1167,4 +1168,18 @@ public class JsonReader implements Closeable {
     snippet.append(buffer, pos, afterPos);
     return snippet;
   }
+
+  static {
+    JsonReaderInternalAccess.INSTANCE = new JsonReaderInternalAccess() {
+      @Override public void promoteNameToValue(JsonReader reader) throws IOException {
+        reader.quickPeek();
+        if (reader.token != JsonToken.NAME) {
+          throw new IllegalStateException("Expected a name but was " + reader.peek());
+        }
+        reader.value = reader.name;
+        reader.name = null;
+        reader.token = JsonToken.STRING;
+      }
+    };
+  }
 }