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      1 /*
      2  * Copyright 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 #include "bcc/Support/InputFile.h"
     18 
     19 #include "bcc/Support/Log.h"
     20 
     21 using namespace bcc;
     22 
     23 InputFile::InputFile(const std::string &pFilename, unsigned pFlags)
     24   : super(pFilename, pFlags) { }
     25 
     26 ssize_t InputFile::read(void *pBuf, size_t count) {
     27   if ((mFD < 0) || hasError()) {
     28     return -1;
     29   }
     30 
     31   if ((count <= 0) || (pBuf == NULL)) {
     32     // Keep safe and issue a warning.
     33     ALOGW("InputFile::read: count = %zu, buffer = %p", count, pBuf);
     34     return 0;
     35   }
     36 
     37   while (count > 0) {
     38     ssize_t read_size = ::read(mFD, pBuf, count);
     39 
     40     if (read_size >= 0) {
     41       return read_size;
     42     } else if ((errno == EAGAIN) || (errno == EINTR)) {
     43       // If the errno is EAGAIN or EINTR, then we try to read again.
     44       //
     45       // Fall-through
     46     } else {
     47       detectError();
     48       return -1;
     49     }
     50   }
     51   // unreachable
     52   return 0;
     53 }
     54