yanglimingcn commented on code in PR #3062: URL: https://github.com/apache/brpc/pull/3062#discussion_r2272441790
########## src/butil/iobuf.cpp: ########## @@ -1976,6 +1976,259 @@ size_t IOBufCutter::cutn(void* out, size_t n) { } } +SingleIOBuf::SingleIOBuf() + : _cur_block(NULL) + , _block_size(0) { + _cur_ref.offset = 0; + _cur_ref.length = 0; + _cur_ref.block = NULL; +} + +SingleIOBuf::SingleIOBuf(const IOBuf::BlockRef& ref) { + _cur_block = NULL; + _block_size = 0; + if (ref.block) { + _cur_ref = ref; + _cur_ref.block->inc_ref(); + } +} + +SingleIOBuf::SingleIOBuf(const SingleIOBuf& other) { + _cur_block = NULL; + _block_size = 0; + if (other._cur_ref.block != NULL) { + _cur_ref = other._cur_ref; + _cur_ref.block->inc_ref(); + } +} + +SingleIOBuf::~SingleIOBuf() { + reset(); +} + +SingleIOBuf& SingleIOBuf::operator=(const SingleIOBuf& rhs) { + reset(); + _block_size = 0; + if (rhs._cur_ref.block != NULL) { + _cur_ref = rhs._cur_ref; + _cur_ref.block->inc_ref(); + } + return *this; +} + +void* SingleIOBuf::alloc(uint32_t size) { + IOBuf::Block* b = alloc_block_by_size(size); + if (!b) { + return NULL; + } + _cur_ref.offset = b->size; + _cur_ref.length = size; + _cur_ref.block = b; + b->size += size; + b->inc_ref(); + return b->data + _cur_ref.offset; +} + +void SingleIOBuf::deallocate(void* p) { + if (_cur_ref.block) { + if (_cur_ref.block->data + _cur_ref.offset == (char*)p) { + reset(); + } + } +} + +IOBuf::Block* SingleIOBuf::alloc_block_by_size(uint32_t data_size) { + if (_cur_block != NULL) { + if (_cur_block->left_space() >= data_size) { + return _cur_block; + } else { + _cur_block->dec_ref(); + _cur_block = NULL; + } + } + uint32_t total_size = data_size + sizeof(IOBuf::Block); + if (total_size <= IOBuf::DEFAULT_BLOCK_SIZE) { + _cur_block = iobuf::acquire_tls_block(); + if (_cur_block != NULL) { + if (_cur_block->left_space() >= data_size) { + return _cur_block; + } else { + _cur_block->dec_ref(); + _cur_block = NULL; + } + } + _cur_block = iobuf::create_block(); + } else { + _cur_block = iobuf::create_block(total_size); + _block_size = total_size; + } + if (BAIDU_UNLIKELY(!_cur_block)) { + errno = ENOMEM; + _block_size = 0; + return NULL; + } + return _cur_block; +} + +void SingleIOBuf::memcpy_downward(void* old_p, uint32_t old_size, + void* new_p, uint32_t new_size, + uint32_t in_use_back, uint32_t in_use_front) { + memcpy((u_char*)new_p + new_size - in_use_back, (u_char*)old_p + old_size - in_use_back, + in_use_back); + memcpy(new_p, old_p, in_use_front); +} + +void* SingleIOBuf::reallocate_downward(uint32_t new_size, uint32_t in_use_back, + uint32_t in_use_front) { + IOBuf::BlockRef& ref = _cur_ref; + if (BAIDU_UNLIKELY(new_size <= ref.length)) { + LOG(ERROR) << "invaild new size:" << new_size; + errno = EINVAL; + return NULL; + } + if (BAIDU_UNLIKELY(ref.block == NULL)) { + LOG(ERROR) << "SingleIOBuf reallocate_downward failed. Block cannot be null!"; + errno = EINVAL; + return NULL; + } + char* old_p = ref.block->data + ref.offset; + uint32_t old_size = ref.length; + IOBuf::Block* b = alloc_block_by_size(new_size); + if (!b) { + return NULL; + } + char* new_p = b->data + b->size; + memcpy_downward(old_p, old_size, + new_p, new_size, + in_use_back, in_use_front); + ref.block->dec_ref(); + _cur_ref.offset = b->size; + _cur_ref.length = new_size; + _cur_ref.block = b; + b->size += new_size; + b->inc_ref(); + return new_p; +} + +const void* SingleIOBuf::get_begin() const { + if (_cur_ref.block) { + return _cur_ref.block->data + _cur_ref.offset; + } + return NULL; +} + +uint32_t SingleIOBuf::get_length() const { + return _cur_ref.length; +} + +void SingleIOBuf::reset() { + if (_cur_block) { + if (_block_size == 0) { + iobuf::release_tls_block(_cur_block); + } else { + _cur_block->dec_ref(); + _block_size = 0; + } + _cur_block = NULL; + } + if (_cur_ref.block != NULL) { + _cur_ref.block->dec_ref(); + } + _cur_ref.offset = 0; + _cur_ref.length = 0; + _cur_ref.block = NULL; +} + +void SingleIOBuf::target_block_inc_ref(void* b) { + IOBuf::Block* block = (IOBuf::Block*)b; + block->inc_ref(); +} + +void SingleIOBuf::target_block_dec_ref(void* b) { + IOBuf::Block* block = (IOBuf::Block*)b; + block->dec_ref(); +} + +bool SingleIOBuf::assign(const IOBuf& buf, uint32_t msg_size) { + if (BAIDU_UNLIKELY(buf.length() < msg_size)) { + LOG(ERROR) << "Fail to dump_mult_iobuf msg_size:" << msg_size + << " from source iobuf of size:" << buf.length(); + return false; + } + reset(); + if (BAIDU_UNLIKELY(msg_size == 0)) { + return true; + } + const IOBuf::BlockRef& ref = buf._front_ref(); + if (ref.length >= msg_size) { + _cur_ref.offset = ref.offset; + _cur_ref.length = msg_size; + _cur_ref.block = ref.block; + _cur_ref.block->inc_ref(); + return true; + } else { + IOBuf::Block* b = alloc_block_by_size(msg_size); + if (!b) { + return false; + } + char* out = b->data + b->size; + const size_t nref = buf.backing_block_num(); + uint32_t last_len = msg_size; + for (size_t i = 0; i < nref && last_len > 0; ++i) { + const IOBuf::BlockRef& r = buf._ref_at(i); + uint32_t n = std::min(r.length, last_len); + iobuf::cp(out, r.block->data + r.offset, n); + last_len -= n; + out += n; + } + _cur_ref.offset = b->size; + _cur_ref.length = msg_size; + _cur_ref.block = b; + b->size += msg_size; + _cur_ref.block->inc_ref(); + return true; + } + return false; +} + +void SingleIOBuf::append_to(IOBuf* buf) const { Review Comment: In RPC scenarios, data length is dynamic, while SingleIOBuf typically manages a fixed-size memory block. would you please explain how to use it in PRC parse message and pack message? for example, when receive a message we don't know the length of this message, how to allocate memory, if memory is short, we need to reallocate and need memcopy? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@brpc.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@brpc.apache.org For additional commands, e-mail: dev-h...@brpc.apache.org