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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_INDENTER_H_
     18 #define ART_RUNTIME_INDENTER_H_
     19 
     20 #include "base/logging.h"
     21 #include "base/macros.h"
     22 #include <streambuf>
     23 
     24 const char kIndentChar =' ';
     25 const size_t kIndentBy1Count = 2;
     26 
     27 class Indenter : public std::streambuf {
     28  public:
     29   Indenter(std::streambuf* out, char text, size_t count)
     30       : indent_next_(true), out_sbuf_(out), text_(text), count_(count) {}
     31 
     32  private:
     33   int_type overflow(int_type c) {
     34     if (UNLIKELY(c == std::char_traits<char>::eof())) {
     35       out_sbuf_->pubsync();
     36       return c;
     37     }
     38     if (indent_next_) {
     39       for (size_t i = 0; i < count_; ++i) {
     40         int_type r = out_sbuf_->sputc(text_);
     41         if (UNLIKELY(r != text_)) {
     42           out_sbuf_->pubsync();
     43           r = out_sbuf_->sputc(text_);
     44           CHECK_EQ(r, text_) << "Error writing to buffer. Disk full?";
     45         }
     46       }
     47     }
     48     indent_next_ = (c == '\n');
     49     int_type r = out_sbuf_->sputc(c);
     50     if (UNLIKELY(r != c)) {
     51       out_sbuf_->pubsync();
     52       r = out_sbuf_->sputc(c);
     53       CHECK_EQ(r, c) << "Error writing to buffer. Disk full?";
     54     }
     55     return r;
     56   }
     57 
     58   int sync() {
     59     return out_sbuf_->pubsync();
     60   }
     61 
     62   bool indent_next_;
     63 
     64   // Buffer to write output to.
     65   std::streambuf* const out_sbuf_;
     66 
     67   // Text output as indent.
     68   const char text_;
     69 
     70   // Number of times text is output.
     71   const size_t count_;
     72 
     73   DISALLOW_COPY_AND_ASSIGN(Indenter);
     74 };
     75 
     76 #endif  // ART_RUNTIME_INDENTER_H_
     77