THRIFT-926. cpp: TMemoryBuffer: Uphold the strong exception safety guarantee
Previously, if we had a realloc failure when growing a TMemoryBuffer, we
would leave the buffer in an invalid state (bufferSize_ would reflect
the desired size, rather than the actual size). Now, we make no change
to any member variables if realloc fails.
git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@1005165 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/cpp/src/transport/TBufferTransports.cpp b/lib/cpp/src/transport/TBufferTransports.cpp
index 6ba70e2..45913f4 100644
--- a/lib/cpp/src/transport/TBufferTransports.cpp
+++ b/lib/cpp/src/transport/TBufferTransports.cpp
@@ -324,24 +324,25 @@
}
// Grow the buffer as necessary.
+ uint32_t new_size = bufferSize_;
while (len > avail) {
- bufferSize_ *= 2;
- wBound_ = buffer_ + bufferSize_;
- avail = available_write();
+ new_size = new_size > 0 ? new_size * 2 : 1;
+ avail = available_write() + (new_size - bufferSize_);
}
// Allocate into a new pointer so we don't bork ours if it fails.
- void* new_buffer = std::realloc(buffer_, bufferSize_);
+ void* new_buffer = std::realloc(buffer_, new_size);
if (new_buffer == NULL) {
throw TTransportException("Out of memory.");
}
+ bufferSize_ = new_size;
ptrdiff_t offset = (uint8_t*)new_buffer - buffer_;
buffer_ += offset;
rBase_ += offset;
rBound_ += offset;
wBase_ += offset;
- wBound_ += offset;
+ wBound_ = buffer_ + bufferSize_;
}
void TMemoryBuffer::writeSlow(const uint8_t* buf, uint32_t len) {