add -r to DM

dm/DMJsonWriter.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "DMJsonWriter.h"
 
 #include "SkCommonFlags.h"
+#include "SkData.h"
 #include "SkJSONCPP.h"
 #include "SkOSFile.h"
 #include "SkStream.h"
 #include "SkTArray.h"
 #include "SkThread.h"
 
 namespace DM {
 
 SkTArray<JsonWriter::BitmapResult> gBitmapResults;
 SK_DECLARE_STATIC_MUTEX(gBitmapResultLock);
@@ skipping 51 matching lines @@
             root["test_results"]["failures"].append(result);
         }
     }
 
     SkString path = SkOSPath::Join(FLAGS_writePath[0], "dm.json");
     SkFILEWStream stream(path.c_str());
     stream.writeText(Json::StyledWriter().write(root).c_str());
     stream.flush();
 }
 
+bool JsonWriter::ReadJson(const char* path, void(*callback)(BitmapResult)) {
+    SkAutoTUnref<SkData> json(SkData::NewFromFileName(path));
+    if (!json) {
+        return false;
+    }
+
+    Json::Reader reader;
+    Json::Value root;
+    const char* data = (const char*)json->data();
+    if (!reader.parse(data, data+json->size(), root)) {
+        return false;
+    }
+
+    const Json::Value& results = root["results"];
+    BitmapResult br;
+    for (unsigned i = 0; i < results.size(); i++) {
+        const Json::Value& r = results[i];
+        br.name       = r["key"]["name"].asCString();
+        br.config     = r["key"]["config"].asCString();
+        br.sourceType = r["key"]["source_type"].asCString();
+        br.ext        = r["ext"].asCString();
+        br.md5        = r["md5"].asCString();
+        callback(br);
+    }
+    return true;
+}
+
 } // namespace DM