Add JSON output option to bench.

bench/ResultsWriter.h

Index: bench/ResultsWriter.h
===================================================================
--- bench/ResultsWriter.h	(revision 0)
+++ bench/ResultsWriter.h	(revision 0)
@@ -0,0 +1,175 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Classes for writing out bench results in various formats.
+ */
+#ifndef SkResultsWriter_DEFINED
+#define SkResultsWriter_DEFINED
+
+#include "SkBenchLogger.h"
+#include "SkJSONCPP.h"
+#include "SkStream.h"
+#include "SkString.h"
+#include "SkTArray.h"
+#include "SkTypes.h"
+
+
+/**
+ * Base class for writing out the bench results.
+ *
+ * TODO(jcgregorio) Add info if tests fail to converge?
+ */
+class ResultsWriter : SkNoncopyable {
+public:
+    virtual ~ResultsWriter() {};
+
+    // Records one option set for this run. All options must be set before
+    // calling bench().
+    virtual void option(const char name[], const char value[]) = 0;
+
+    // Denotes the start of a specific benchmark. Once bench is called,
+    // then config and timer can be called multiple times to record runs.
+    virtual void bench(const char name[], int32_t x, int32_t y) = 0;
+
+    // Records the specific configuration a bench is run under, such as "8888".
+    virtual void config(const char name[]) = 0;
+
+    // Records a single test metric.
+    virtual void timer(const char name[], double ms) = 0;
+
+    // Call when all results are finished.
+    virtual void end() = 0;
+};
+
+/**
+ * This ResultsWriter handles writing out the human readable format of the
+ * bench results.
+ */
+class LoggerResultsWriter : public ResultsWriter {
+public:
+    explicit LoggerResultsWriter(SkBenchLogger& logger, const char* timeFormat)
+        : fLogger(logger)
+        , fTimeFormat(timeFormat) {
+        fLogger.logProgress("skia bench:");
+    }
+    virtual void option(const char name[], const char value[]) {
+        fLogger.logProgress(SkStringPrintf(" %s=%s", name, value));
+    }
+    virtual void bench(const char name[], int32_t x, int32_t y) {
+        fLogger.logProgress(SkStringPrintf(
+            "\nrunning bench [%3d %3d] %040s", x, y, name));
+    }
+    virtual void config(const char name[]) {
+        fLogger.logProgress(SkStringPrintf("   %s:", name));
+    }
+    virtual void timer(const char name[], double ms) {
+        fLogger.logProgress(SkStringPrintf("  %s = ", name));
+        fLogger.logProgress(SkStringPrintf(fTimeFormat, ms));
+    }
+    virtual void end() {
+        fLogger.logProgress("\n");
+    }
+private:
+    SkBenchLogger& fLogger;
+    const char* fTimeFormat;
+};
+
+/**
+ * This ResultsWriter handles writing out the results in JSON.
+ *
+ * The output looks like:
+ *
+ *  {
+ *   "options" : {
+ *      "alpha" : "0xFF",
+ *      "scale" : "0",
+ *      ...
+ *      "system" : "UNIX"
+ *   },
+ *   "results" : {
+ *      "Xfermode_Luminosity_640_480" : {
+ *         "565" : {
+ *            "cmsecs" : 143.188128906250,
+ *            "msecs" : 143.835957031250
+ *         },
+ *         ...
+ */
+class JSONResultsWriter : public ResultsWriter {
+public:
+    explicit JSONResultsWriter(const char filename[])
+        : fFilename(filename)
+        , fRoot()
+        , fResults(fRoot["results"])
+        , fBench(NULL)
+        , fConfig(NULL) {
+    }
+    virtual void option(const char name[], const char value[]) {
+        fRoot["options"][name] = value;
+    }
+    virtual void bench(const char name[], int32_t x, int32_t y) {
+        fBench = &fResults[SkStringPrintf( "%s_%d_%d", name, x, y).c_str()];
+    }
+    virtual void config(const char name[]) {
+        SkASSERT(NULL != fBench);
+        fConfig = &(*fBench)[name];
+    }
+    virtual void timer(const char name[], double ms) {
+        SkASSERT(NULL != fConfig);
+        (*fConfig)[name] = ms;
+    }
+    virtual void end() {
+        SkFILEWStream stream(fFilename.c_str());
+        stream.writeText(fRoot.toStyledString().c_str());
+        stream.flush();
+    }
+private:
+    SkString fFilename;
+    Json::Value fRoot;
+    Json::Value& fResults;
+    Json::Value* fBench;
+    Json::Value* fConfig;
+};
+
+/**
+ * This ResultsWriter writes out to multiple ResultsWriters.
+ */
+class MultiResultsWriter : public ResultsWriter {
+public:
+    MultiResultsWriter() : writers() {
+    };
+    void add(ResultsWriter* writer) {
+      writers.push_back(writer);
+    }
+    virtual void option(const char name[], const char value[]) {
+        for (int i = 0; i < writers.count(); ++i) {
+            writers[i]->option(name, value);
+        }
+    }
+    virtual void bench(const char name[], int32_t x, int32_t y) {
+        for (int i = 0; i < writers.count(); ++i) {
+            writers[i]->bench(name, x, y);
+        }
+    }
+    virtual void config(const char name[]) {
+        for (int i = 0; i < writers.count(); ++i) {
+            writers[i]->config(name);
+        }
+    }
+    virtual void timer(const char name[], double ms) {
+        for (int i = 0; i < writers.count(); ++i) {
+            writers[i]->timer(name, ms);
+        }
+    }
+    virtual void end() {
+        for (int i = 0; i < writers.count(); ++i) {
+            writers[i]->end();
+        }
+    }
+private:
+    SkTArray<ResultsWriter *> writers;
+};
+
+#endif