Linux: Add Breakpad client.

breakpad/linux/line_reader.h

Index: breakpad/linux/line_reader.h
diff --git a/breakpad/linux/line_reader.h b/breakpad/linux/line_reader.h
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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.
+
+#include <stdint.h>
+#include <assert.h>
+#include <string.h>
+
+#include "breakpad/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