diff options
Diffstat (limited to 'include/google/protobuf/io/zero_copy_stream_impl_lite.h')
| -rw-r--r-- | include/google/protobuf/io/zero_copy_stream_impl_lite.h | 413 |
1 files changed, 0 insertions, 413 deletions
diff --git a/include/google/protobuf/io/zero_copy_stream_impl_lite.h b/include/google/protobuf/io/zero_copy_stream_impl_lite.h deleted file mode 100644 index cbda32871e..0000000000 --- a/include/google/protobuf/io/zero_copy_stream_impl_lite.h +++ /dev/null @@ -1,413 +0,0 @@ -// Protocol Buffers - Google's data interchange format -// Copyright 2008 Google Inc. All rights reserved. -// https://developers.google.com/protocol-buffers/ -// -// 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. - -// Author: kenton@google.com (Kenton Varda) -// Based on original Protocol Buffers design by -// Sanjay Ghemawat, Jeff Dean, and others. -// -// This file contains common implementations of the interfaces defined in -// zero_copy_stream.h which are included in the "lite" protobuf library. -// These implementations cover I/O on raw arrays and strings, as well as -// adaptors which make it easy to implement streams based on traditional -// streams. Of course, many users will probably want to write their own -// implementations of these interfaces specific to the particular I/O -// abstractions they prefer to use, but these should cover the most common -// cases. - -#ifndef GOOGLE_PROTOBUF_IO_ZERO_COPY_STREAM_IMPL_LITE_H__ -#define GOOGLE_PROTOBUF_IO_ZERO_COPY_STREAM_IMPL_LITE_H__ - - -#include <iosfwd> -#include <memory> -#include <string> - -#include <google/protobuf/stubs/callback.h> -#include <google/protobuf/stubs/common.h> -#include <google/protobuf/io/zero_copy_stream.h> -#include <google/protobuf/stubs/stl_util.h> - - -// Must be included last. -#include <google/protobuf/port_def.inc> - -namespace google { -namespace protobuf { -namespace io { - -// =================================================================== - -// A ZeroCopyInputStream backed by an in-memory array of bytes. -class PROTOBUF_EXPORT ArrayInputStream PROTOBUF_FUTURE_FINAL - : public ZeroCopyInputStream { - public: - // Create an InputStream that returns the bytes pointed to by "data". - // "data" remains the property of the caller but must remain valid until - // the stream is destroyed. If a block_size is given, calls to Next() - // will return data blocks no larger than the given size. Otherwise, the - // first call to Next() returns the entire array. block_size is mainly - // useful for testing; in production you would probably never want to set - // it. - ArrayInputStream(const void* data, int size, int block_size = -1); - ~ArrayInputStream() override = default; - - // implements ZeroCopyInputStream ---------------------------------- - bool Next(const void** data, int* size) override; - void BackUp(int count) override; - bool Skip(int count) override; - int64_t ByteCount() const override; - - - private: - const uint8_t* const data_; // The byte array. - const int size_; // Total size of the array. - const int block_size_; // How many bytes to return at a time. - - int position_; - int last_returned_size_; // How many bytes we returned last time Next() - // was called (used for error checking only). - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ArrayInputStream); -}; - -// =================================================================== - -// A ZeroCopyOutputStream backed by an in-memory array of bytes. -class PROTOBUF_EXPORT ArrayOutputStream PROTOBUF_FUTURE_FINAL - : public ZeroCopyOutputStream { - public: - // Create an OutputStream that writes to the bytes pointed to by "data". - // "data" remains the property of the caller but must remain valid until - // the stream is destroyed. If a block_size is given, calls to Next() - // will return data blocks no larger than the given size. Otherwise, the - // first call to Next() returns the entire array. block_size is mainly - // useful for testing; in production you would probably never want to set - // it. - ArrayOutputStream(void* data, int size, int block_size = -1); - ~ArrayOutputStream() override = default; - - // implements ZeroCopyOutputStream --------------------------------- - bool Next(void** data, int* size) override; - void BackUp(int count) override; - int64_t ByteCount() const override; - - private: - uint8_t* const data_; // The byte array. - const int size_; // Total size of the array. - const int block_size_; // How many bytes to return at a time. - - int position_; - int last_returned_size_; // How many bytes we returned last time Next() - // was called (used for error checking only). - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ArrayOutputStream); -}; - -// =================================================================== - -// A ZeroCopyOutputStream which appends bytes to a string. -class PROTOBUF_EXPORT StringOutputStream PROTOBUF_FUTURE_FINAL - : public ZeroCopyOutputStream { - public: - // Create a StringOutputStream which appends bytes to the given string. - // The string remains property of the caller, but it is mutated in arbitrary - // ways and MUST NOT be accessed in any way until you're done with the - // stream. Either be sure there's no further usage, or (safest) destroy the - // stream before using the contents. - // - // Hint: If you call target->reserve(n) before creating the stream, - // the first call to Next() will return at least n bytes of buffer - // space. - explicit StringOutputStream(std::string* target); - ~StringOutputStream() override = default; - - // implements ZeroCopyOutputStream --------------------------------- - bool Next(void** data, int* size) override; - void BackUp(int count) override; - int64_t ByteCount() const override; - - private: - static constexpr size_t kMinimumSize = 16; - - std::string* target_; - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(StringOutputStream); -}; - -// Note: There is no StringInputStream. Instead, just create an -// ArrayInputStream as follows: -// ArrayInputStream input(str.data(), str.size()); - -// =================================================================== - -// A generic traditional input stream interface. -// -// Lots of traditional input streams (e.g. file descriptors, C stdio -// streams, and C++ iostreams) expose an interface where every read -// involves copying bytes into a buffer. If you want to take such an -// interface and make a ZeroCopyInputStream based on it, simply implement -// CopyingInputStream and then use CopyingInputStreamAdaptor. -// -// CopyingInputStream implementations should avoid buffering if possible. -// CopyingInputStreamAdaptor does its own buffering and will read data -// in large blocks. -class PROTOBUF_EXPORT CopyingInputStream { - public: - virtual ~CopyingInputStream() {} - - // Reads up to "size" bytes into the given buffer. Returns the number of - // bytes read. Read() waits until at least one byte is available, or - // returns zero if no bytes will ever become available (EOF), or -1 if a - // permanent read error occurred. - virtual int Read(void* buffer, int size) = 0; - - // Skips the next "count" bytes of input. Returns the number of bytes - // actually skipped. This will always be exactly equal to "count" unless - // EOF was reached or a permanent read error occurred. - // - // The default implementation just repeatedly calls Read() into a scratch - // buffer. - virtual int Skip(int count); -}; - -// A ZeroCopyInputStream which reads from a CopyingInputStream. This is -// useful for implementing ZeroCopyInputStreams that read from traditional -// streams. Note that this class is not really zero-copy. -// -// If you want to read from file descriptors or C++ istreams, this is -// already implemented for you: use FileInputStream or IstreamInputStream -// respectively. -class PROTOBUF_EXPORT CopyingInputStreamAdaptor : public ZeroCopyInputStream { - public: - // Creates a stream that reads from the given CopyingInputStream. - // If a block_size is given, it specifies the number of bytes that - // should be read and returned with each call to Next(). Otherwise, - // a reasonable default is used. The caller retains ownership of - // copying_stream unless SetOwnsCopyingStream(true) is called. - explicit CopyingInputStreamAdaptor(CopyingInputStream* copying_stream, - int block_size = -1); - ~CopyingInputStreamAdaptor() override; - - // Call SetOwnsCopyingStream(true) to tell the CopyingInputStreamAdaptor to - // delete the underlying CopyingInputStream when it is destroyed. - void SetOwnsCopyingStream(bool value) { owns_copying_stream_ = value; } - - // implements ZeroCopyInputStream ---------------------------------- - bool Next(const void** data, int* size) override; - void BackUp(int count) override; - bool Skip(int count) override; - int64_t ByteCount() const override; - - private: - // Insures that buffer_ is not NULL. - void AllocateBufferIfNeeded(); - // Frees the buffer and resets buffer_used_. - void FreeBuffer(); - - // The underlying copying stream. - CopyingInputStream* copying_stream_; - bool owns_copying_stream_; - - // True if we have seen a permanent error from the underlying stream. - bool failed_; - - // The current position of copying_stream_, relative to the point where - // we started reading. - int64_t position_; - - // Data is read into this buffer. It may be NULL if no buffer is currently - // in use. Otherwise, it points to an array of size buffer_size_. - std::unique_ptr<uint8_t[]> buffer_; - const int buffer_size_; - - // Number of valid bytes currently in the buffer (i.e. the size last - // returned by Next()). 0 <= buffer_used_ <= buffer_size_. - int buffer_used_; - - // Number of bytes in the buffer which were backed up over by a call to - // BackUp(). These need to be returned again. - // 0 <= backup_bytes_ <= buffer_used_ - int backup_bytes_; - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingInputStreamAdaptor); -}; - -// =================================================================== - -// A generic traditional output stream interface. -// -// Lots of traditional output streams (e.g. file descriptors, C stdio -// streams, and C++ iostreams) expose an interface where every write -// involves copying bytes from a buffer. If you want to take such an -// interface and make a ZeroCopyOutputStream based on it, simply implement -// CopyingOutputStream and then use CopyingOutputStreamAdaptor. -// -// CopyingOutputStream implementations should avoid buffering if possible. -// CopyingOutputStreamAdaptor does its own buffering and will write data -// in large blocks. -class PROTOBUF_EXPORT CopyingOutputStream { - public: - virtual ~CopyingOutputStream() {} - - // Writes "size" bytes from the given buffer to the output. Returns true - // if successful, false on a write error. - virtual bool Write(const void* buffer, int size) = 0; -}; - -// A ZeroCopyOutputStream which writes to a CopyingOutputStream. This is -// useful for implementing ZeroCopyOutputStreams that write to traditional -// streams. Note that this class is not really zero-copy. -// -// If you want to write to file descriptors or C++ ostreams, this is -// already implemented for you: use FileOutputStream or OstreamOutputStream -// respectively. -class PROTOBUF_EXPORT CopyingOutputStreamAdaptor : public ZeroCopyOutputStream { - public: - // Creates a stream that writes to the given Unix file descriptor. - // If a block_size is given, it specifies the size of the buffers - // that should be returned by Next(). Otherwise, a reasonable default - // is used. - explicit CopyingOutputStreamAdaptor(CopyingOutputStream* copying_stream, - int block_size = -1); - ~CopyingOutputStreamAdaptor() override; - - // Writes all pending data to the underlying stream. Returns false if a - // write error occurred on the underlying stream. (The underlying - // stream itself is not necessarily flushed.) - bool Flush(); - - // Call SetOwnsCopyingStream(true) to tell the CopyingOutputStreamAdaptor to - // delete the underlying CopyingOutputStream when it is destroyed. - void SetOwnsCopyingStream(bool value) { owns_copying_stream_ = value; } - - // implements ZeroCopyOutputStream --------------------------------- - bool Next(void** data, int* size) override; - void BackUp(int count) override; - int64_t ByteCount() const override; - bool WriteAliasedRaw(const void* data, int size) override; - bool AllowsAliasing() const override { return true; } - - private: - // Write the current buffer, if it is present. - bool WriteBuffer(); - // Insures that buffer_ is not NULL. - void AllocateBufferIfNeeded(); - // Frees the buffer. - void FreeBuffer(); - - // The underlying copying stream. - CopyingOutputStream* copying_stream_; - bool owns_copying_stream_; - - // True if we have seen a permanent error from the underlying stream. - bool failed_; - - // The current position of copying_stream_, relative to the point where - // we started writing. - int64_t position_; - - // Data is written from this buffer. It may be NULL if no buffer is - // currently in use. Otherwise, it points to an array of size buffer_size_. - std::unique_ptr<uint8_t[]> buffer_; - const int buffer_size_; - - // Number of valid bytes currently in the buffer (i.e. the size last - // returned by Next()). When BackUp() is called, we just reduce this. - // 0 <= buffer_used_ <= buffer_size_. - int buffer_used_; - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingOutputStreamAdaptor); -}; - -// =================================================================== - -// A ZeroCopyInputStream which wraps some other stream and limits it to -// a particular byte count. -class PROTOBUF_EXPORT LimitingInputStream PROTOBUF_FUTURE_FINAL - : public ZeroCopyInputStream { - public: - LimitingInputStream(ZeroCopyInputStream* input, int64_t limit); - ~LimitingInputStream() override; - - // implements ZeroCopyInputStream ---------------------------------- - bool Next(const void** data, int* size) override; - void BackUp(int count) override; - bool Skip(int count) override; - int64_t ByteCount() const override; - - - private: - ZeroCopyInputStream* input_; - int64_t limit_; // Decreases as we go, becomes negative if we overshoot. - int64_t prior_bytes_read_; // Bytes read on underlying stream at construction - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(LimitingInputStream); -}; - - -// =================================================================== - -// mutable_string_data() and as_string_data() are workarounds to improve -// the performance of writing new data to an existing string. Unfortunately -// the methods provided by the string class are suboptimal, and using memcpy() -// is mildly annoying because it requires its pointer args to be non-NULL even -// if we ask it to copy 0 bytes. Furthermore, string_as_array() has the -// property that it always returns NULL if its arg is the empty string, exactly -// what we want to avoid if we're using it in conjunction with memcpy()! -// With C++11, the desired memcpy() boils down to memcpy(..., &(*s)[0], size), -// where s is a string*. Without C++11, &(*s)[0] is not guaranteed to be safe, -// so we use string_as_array(), and live with the extra logic that tests whether -// *s is empty. - -// Return a pointer to mutable characters underlying the given string. The -// return value is valid until the next time the string is resized. We -// trust the caller to treat the return value as an array of length s->size(). -inline char* mutable_string_data(std::string* s) { - // This should be simpler & faster than string_as_array() because the latter - // is guaranteed to return NULL when *s is empty, so it has to check for that. - return &(*s)[0]; -} - -// as_string_data(s) is equivalent to -// ({ char* p = mutable_string_data(s); make_pair(p, p != NULL); }) -// Sometimes it's faster: in some scenarios p cannot be NULL, and then the -// code can avoid that check. -inline std::pair<char*, bool> as_string_data(std::string* s) { - char* p = mutable_string_data(s); - return std::make_pair(p, true); -} - -} // namespace io -} // namespace protobuf -} // namespace google - -#include <google/protobuf/port_undef.inc> - -#endif // GOOGLE_PROTOBUF_IO_ZERO_COPY_STREAM_IMPL_LITE_H__ |