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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef TOOLS_BLINK_GC_PLUGIN_JSON_WRITER_H_
      6 #define TOOLS_BLINK_GC_PLUGIN_JSON_WRITER_H_
      7 
      8 #include "llvm/Support/raw_ostream.h"
      9 
     10 // Helper to write information for the points-to graph.
     11 class JsonWriter {
     12  public:
     13   static JsonWriter* from(llvm::raw_fd_ostream* os) {
     14     return os ? new JsonWriter(os) : 0;
     15   }
     16   ~JsonWriter() {
     17     os_.close();
     18   }
     19   void OpenList() {
     20     Separator();
     21     os_ << "[";
     22     state_.push(false);
     23   }
     24   void OpenList(const std::string key) {
     25     Write(key);
     26     os_ << ":";
     27     OpenList();
     28   }
     29   void CloseList() {
     30     os_ << "]";
     31     state_.pop();
     32   }
     33   void OpenObject() {
     34     Separator();
     35     os_ << "{";
     36     state_.push(false);
     37   }
     38   void CloseObject() {
     39     os_ << "}\n";
     40     state_.pop();
     41   }
     42   void Write(const size_t val) {
     43     Separator();
     44     os_ << val;
     45   }
     46   void Write(const std::string val) {
     47     Separator();
     48     os_ << "\"" << val << "\"";
     49   }
     50   void Write(const std::string key, const size_t val) {
     51     Separator();
     52     os_ << "\"" << key << "\":" << val;
     53   }
     54   void Write(const std::string key, const std::string val) {
     55     Separator();
     56     os_ << "\"" << key << "\":\"" << val << "\"";
     57   }
     58  private:
     59   JsonWriter(llvm::raw_fd_ostream* os) : os_(*os) {}
     60   void Separator() {
     61     if (state_.empty())
     62       return;
     63     if (state_.top()) {
     64       os_ << ",";
     65       return;
     66     }
     67     state_.top() = true;
     68   }
     69   llvm::raw_fd_ostream& os_;
     70   std::stack<bool> state_;
     71 };
     72 
     73 #endif // TOOLS_BLINK_GC_PLUGIN_JSON_WRITER_H_
     74