Add batch names and bounds to json debug information

src/gpu/GrAuditTrail.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAuditTrail.h"
 
+template <class T>
+static void jsonify_tarray(SkString* json, const SkTArray<T>& array) {
+    for (int i = 0; i < array.count(); i++) {
+        json->append(array[i].toJson());
+        if (i < array.count() - 1) {
+            json->append(",");
+        }
+    }
+}
+
+// This will pretty print a very small subset of json
+// The parsing rules are straightforward, aside from the fact that we do not want an extra newline
+// before ',' and after '}', so we have a comma exception rule.
+class PrettyPrintJson {
+public:
+    SkString prettify(const SkString& json) {
+        fPrettyJson.reset();
+        fTabCount = 0;
+        fFreshLine = false;
+        fCommaException = false;
+        for (size_t i = 0; i < json.size(); i++) {
+            if ('[' == json[i] || '{' == json[i]) {
+                this->newline();
+                this->appendChar(json[i]);
+                fTabCount++;
+                this->newline();
+            } else if (']' == json[i] || '}' == json[i]) {
+                fTabCount--;
+                this->newline();
+                this->appendChar(json[i]);
+                fCommaException = true;
+            } else if (',' == json[i]) {
+                this->appendChar(json[i]);
+                this->newline();
+            } else {
+                this->appendChar(json[i]);
+            }
+        }
+        return fPrettyJson;
+    }
+private:
+    void appendChar(char appendee) {
+        if (fCommaException && ',' != appendee) {
+            this->newline();
+        }
+        this->tab();
+        fPrettyJson += appendee;
+        fFreshLine = false;
+        fCommaException = false;
+    }
+
+    void tab() {
+        if (fFreshLine) {
+            for (int i = 0; i < fTabCount; i++) {
+                fPrettyJson += '\t';
+            }
+        }
+    }
+
+    void newline() {
+        if (!fFreshLine) {
+            fFreshLine = true;
+            fPrettyJson += '\n';
+        }
+    }
+
+    SkString fPrettyJson;
+    int fTabCount;
+    bool fFreshLine;
+    bool fCommaException;
+};
+
+static SkString pretty_print_json(SkString json) {
+    class PrettyPrintJson prettyPrintJson;
+    return prettyPrintJson.prettify(json);
+}
+
 SkString GrAuditTrail::toJson() const {
     SkString json;
-    json.append("{\n");
-    json.append("\"Ops\": [\n");
-    for (int i = 0; i < fOps.count(); i++) {
-        json.append(fOps[i].toJson());
-        if (i < fOps.count() - 1) {
-            json.append(",\n");
-        }
-    }
-    json.append("]\n");
-    json.append("}\n");
-    return json;
+    json.append("{");
+    json.append("\"Ops\": [");
+    jsonify_tarray(&json, fOps);
+    json.append("]");
+    json.append("}");
+
+    // TODO if this becomes a performance issue we should make pretty print configurable
+    return pretty_print_json(json);
 }
 
 SkString GrAuditTrail::Op::toJson() const {
     SkString json;
-    json.append("{\n");
-    json.appendf("\"Name\": \"%s\"\n", fName.c_str());
-    json.append("}\n");
+    json.append("{");
+    json.appendf("\"Name\": \"%s\",", fName.c_str());
+    json.append("\"Batches\": [");
+    jsonify_tarray(&json, fBatches);
+    json.append("]");
+    json.append("}");
     return json;
 }
 
+SkString GrAuditTrail::Op::Batch::toJson() const {
+    SkString json;
+    json.append("{");
+    json.appendf("\"Name\": \"%s\",", fName.c_str());
+    json.append("\"Bounds\": {");
+    json.appendf("\"Left\": %f,", fBounds.fLeft);
+    json.appendf("\"Right\": %f,", fBounds.fRight);
+    json.appendf("\"Top\": %f,", fBounds.fTop);
+    json.appendf("\"Bottom\": %f", fBounds.fBottom);
+    json.append("}");
+    json.append("}");
+    return json;
+}