131 lines
4.2 KiB
C++
131 lines
4.2 KiB
C++
// Copyright (c) 2009, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_
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#define CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_
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#include <stdint.h>
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#include <assert.h>
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#include <string.h>
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#include "third_party/lss/linux_syscall_support.h"
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namespace google_breakpad {
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// A class for reading a file, line by line, without using fopen/fgets or other
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// functions which may allocate memory.
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class LineReader {
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public:
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LineReader(int fd)
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: fd_(fd),
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hit_eof_(false),
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buf_used_(0) {
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}
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// The maximum length of a line.
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static const size_t kMaxLineLen = 512;
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// Return the next line from the file.
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// line: (output) a pointer to the start of the line. The line is NUL
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// terminated.
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// len: (output) the length of the line (not inc the NUL byte)
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//
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// Returns true iff successful (false on EOF).
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//
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// One must call |PopLine| after this function, otherwise you'll continue to
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// get the same line over and over.
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bool GetNextLine(const char **line, unsigned *len) {
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for (;;) {
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if (buf_used_ == 0 && hit_eof_)
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return false;
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for (unsigned i = 0; i < buf_used_; ++i) {
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if (buf_[i] == '\n' || buf_[i] == 0) {
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buf_[i] = 0;
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*len = i;
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*line = buf_;
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return true;
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}
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}
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if (buf_used_ == sizeof(buf_)) {
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// we scanned the whole buffer and didn't find an end-of-line marker.
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// This line is too long to process.
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return false;
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}
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// We didn't find any end-of-line terminators in the buffer. However, if
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// this is the last line in the file it might not have one:
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if (hit_eof_) {
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assert(buf_used_);
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// There's room for the NUL because of the buf_used_ == sizeof(buf_)
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// check above.
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buf_[buf_used_] = 0;
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*len = buf_used_;
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buf_used_ += 1; // since we appended the NUL.
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*line = buf_;
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return true;
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}
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// Otherwise, we should pull in more data from the file
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const ssize_t n = sys_read(fd_, buf_ + buf_used_,
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sizeof(buf_) - buf_used_);
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if (n < 0) {
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return false;
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} else if (n == 0) {
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hit_eof_ = true;
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} else {
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buf_used_ += n;
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}
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// At this point, we have either set the hit_eof_ flag, or we have more
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// data to process...
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}
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}
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void PopLine(unsigned len) {
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// len doesn't include the NUL byte at the end.
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assert(buf_used_ >= len + 1);
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buf_used_ -= len + 1;
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memmove(buf_, buf_ + len + 1, buf_used_);
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}
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private:
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const int fd_;
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bool hit_eof_;
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unsigned buf_used_;
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char buf_[kMaxLineLen];
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};
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} // namespace google_breakpad
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#endif // CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_
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