From 12d8a514c84ee8d60e5d8b8b84aa09dad15197f2 Mon Sep 17 00:00:00 2001
From: Jisi Liu <jisi.liu@gmail.com>
Date: Sat, 7 Feb 2015 12:51:36 -0800
Subject: [PATCH] Get the map factory per mergeFrom() call for JavaNano.

---
 .../java/com/google/protobuf/nano/InternalNano.java   |  5 ++++-
 .../protobuf/compiler/javanano/javanano_helpers.cc    | 11 +++++++++++
 .../protobuf/compiler/javanano/javanano_helpers.h     |  2 ++
 .../protobuf/compiler/javanano/javanano_map_field.cc  |  2 +-
 .../protobuf/compiler/javanano/javanano_message.cc    |  5 +++++
 5 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java b/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java
index f3144652b0..c92ec41761 100644
--- a/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java
+++ b/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java
@@ -30,6 +30,8 @@
 
 package com.google.protobuf.nano;
 
+import com.google.protobuf.nano.MapFactories.MapFactory;
+
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.util.Arrays;
@@ -406,12 +408,13 @@ public final class InternalNano {
   public static final <K, V> Map<K, V> mergeMapEntry(
       CodedInputByteBufferNano input,
       Map<K, V> map,
+      MapFactory mapFactory,
       int keyType,
       int valueType,
       V value,
       int keyTag,
       int valueTag) throws IOException {
-    map = MapFactories.getMapFactory().forMap(map);
+    map = mapFactory.forMap(map);
     final int length = input.readRawVarint32();
     final int oldLimit = input.pushLimit(length);
     K key = null;
diff --git a/src/google/protobuf/compiler/javanano/javanano_helpers.cc b/src/google/protobuf/compiler/javanano/javanano_helpers.cc
index 2149418af6..7b23d9f43d 100644
--- a/src/google/protobuf/compiler/javanano/javanano_helpers.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_helpers.cc
@@ -560,6 +560,17 @@ void SetBitOperationVariables(const string name,
   (*variables)["different_" + name] = GenerateDifferentBit(bitIndex);
 }
 
+bool HasMapField(const Descriptor* descriptor) {
+  for (int i = 0; i < descriptor->field_count(); ++i) {
+    const FieldDescriptor* field = descriptor->field(i);
+    if (field->type() == FieldDescriptor::TYPE_MESSAGE &&
+        IsMapEntry(field->message_type())) {
+      return true;
+    }
+  }
+  return false;
+}
+
 }  // namespace javanano
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/javanano/javanano_helpers.h b/src/google/protobuf/compiler/javanano/javanano_helpers.h
index 5d3532b4ac..b4fee649a3 100644
--- a/src/google/protobuf/compiler/javanano/javanano_helpers.h
+++ b/src/google/protobuf/compiler/javanano/javanano_helpers.h
@@ -187,6 +187,8 @@ inline bool IsMapEntry(const Descriptor* descriptor) {
       descriptor->file()->syntax() == FileDescriptor::SYNTAX_PROTO3;
 }
 
+bool HasMapField(const Descriptor* descriptor);
+
 }  // namespace javanano
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/javanano/javanano_map_field.cc b/src/google/protobuf/compiler/javanano/javanano_map_field.cc
index 117c4f5c04..83b2b0ce8f 100644
--- a/src/google/protobuf/compiler/javanano/javanano_map_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_map_field.cc
@@ -134,7 +134,7 @@ void MapFieldGenerator::
 GenerateMergingCode(io::Printer* printer) const {
   printer->Print(variables_,
     "this.$name$ = com.google.protobuf.nano.InternalNano.mergeMapEntry(\n"
-    "  input, this.$name$,\n"
+    "  input, this.$name$, mapFactory,\n"
     "  com.google.protobuf.nano.InternalNano.$key_desc_type$,\n"
     "  com.google.protobuf.nano.InternalNano.$value_desc_type$,\n"
     "  $value_default$,\n"
diff --git a/src/google/protobuf/compiler/javanano/javanano_message.cc b/src/google/protobuf/compiler/javanano/javanano_message.cc
index 5454d9be0e..da7c656f38 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_message.cc
@@ -345,6 +345,11 @@ void MessageGenerator::GenerateMergeFromMethods(io::Printer* printer) {
     "classname", descriptor_->name());
 
   printer->Indent();
+  if (HasMapField(descriptor_)) {
+    printer->Print(
+      "com.google.protobuf.nano.MapFactories.MapFactory mapFactory =\n"
+      "  com.google.protobuf.nano.MapFactories.getMapFactory();\n");
+  }
 
   printer->Print(
     "while (true) {\n");