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