// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors // Licensed under the MIT License: // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. #pragma once #include <stddef.h> #include "common.h" #include "array.h" #include "exception.h" #include <stdint.h> KJ_BEGIN_HEADER namespace kj { // ======================================================================================= // Abstract interfaces class InputStream { public: virtual ~InputStream() noexcept(false); size_t read(void* buffer, size_t minBytes, size_t maxBytes); // Reads at least minBytes and at most maxBytes, copying them into the given buffer. Returns // the size read. Throws an exception on errors. Implemented in terms of tryRead(). // // maxBytes is the number of bytes the caller really wants, but minBytes is the minimum amount // needed by the caller before it can start doing useful processing. If the stream returns less // than maxBytes, the caller will usually call read() again later to get the rest. Returning // less than maxBytes is useful when it makes sense for the caller to parallelize processing // with I/O. // // Never blocks if minBytes is zero. If minBytes is zero and maxBytes is non-zero, this may // attempt a non-blocking read or may just return zero. To force a read, use a non-zero minBytes. // To detect EOF without throwing an exception, use tryRead(). // // If the InputStream can't produce minBytes, it MUST throw an exception, as the caller is not // expected to understand how to deal with partial reads. virtual size_t tryRead(void* buffer, size_t minBytes, size_t maxBytes) = 0; // Like read(), but may return fewer than minBytes on EOF. inline void read(void* buffer, size_t bytes) { read(buffer, bytes, bytes); } // Convenience method for reading an exact number of bytes. virtual void skip(size_t bytes); // Skips past the given number of bytes, discarding them. The default implementation read()s // into a scratch buffer. String readAllText(uint64_t limit = kj::maxValue); Array<byte> readAllBytes(uint64_t limit = kj::maxValue); // Read until EOF and return as one big byte array or string. Throw an exception if EOF is not // seen before reading `limit` bytes. // // To prevent runaway memory allocation, consider using a more conservative value for `limit` than // the default, particularly on untrusted data streams which may never see EOF. }; class OutputStream { public: virtual ~OutputStream() noexcept(false); virtual void write(const void* buffer, size_t size) = 0; // Always writes the full size. Throws exception on error. virtual void write(ArrayPtr<const ArrayPtr<const byte>> pieces); // Equivalent to write()ing each byte array in sequence, which is what the default implementation // does. Override if you can do something better, e.g. use writev() to do the write in a single // syscall. }; class BufferedInputStream: public InputStream { // An input stream which buffers some bytes in memory to reduce system call overhead. // - OR - // An input stream that actually reads from some in-memory data structure and wants to give its // caller a direct pointer to that memory to potentially avoid a copy. public: virtual ~BufferedInputStream() noexcept(false); ArrayPtr<const byte> getReadBuffer(); // Get a direct pointer into the read buffer, which contains the next bytes in the input. If the // caller consumes any bytes, it should then call skip() to indicate this. This always returns a // non-empty buffer or throws an exception. Implemented in terms of tryGetReadBuffer(). virtual ArrayPtr<const byte> tryGetReadBuffer() = 0; // Like getReadBuffer() but may return an empty buffer on EOF. }; class BufferedOutputStream: public OutputStream { // An output stream which buffers some bytes in memory to reduce system call overhead. // - OR - // An output stream that actually writes into some in-memory data structure and wants to give its // caller a direct pointer to that memory to potentially avoid a copy. public: virtual ~BufferedOutputStream() noexcept(false); virtual ArrayPtr<byte> getWriteBuffer() = 0; // Get a direct pointer into the write buffer. The caller may choose to fill in some prefix of // this buffer and then pass it to write(), in which case write() may avoid a copy. It is // incorrect to pass to write any slice of this buffer which is not a prefix. }; // ======================================================================================= // Buffered streams implemented as wrappers around regular streams class BufferedInputStreamWrapper: public BufferedInputStream { // Implements BufferedInputStream in terms of an InputStream. // // Note that the underlying stream's position is unpredictable once the wrapper is destroyed, // unless the entire stream was consumed. To read a predictable number of bytes in a buffered // way without going over, you'd need this wrapper to wrap some other wrapper which itself // implements an artificial EOF at the desired point. Such a stream should be trivial to write // but is not provided by the library at this time. public: explicit BufferedInputStreamWrapper(InputStream& inner, ArrayPtr<byte> buffer = nullptr); // Creates a buffered stream wrapping the given non-buffered stream. No guarantee is made about // the position of the inner stream after a buffered wrapper has been created unless the entire // input is read. // // If the second parameter is non-null, the stream uses the given buffer instead of allocating // its own. This may improve performance if the buffer can be reused. KJ_DISALLOW_COPY(BufferedInputStreamWrapper); ~BufferedInputStreamWrapper() noexcept(false); // implements BufferedInputStream ---------------------------------- ArrayPtr<const byte> tryGetReadBuffer() override; size_t tryRead(void* buffer, size_t minBytes, size_t maxBytes) override; void skip(size_t bytes) override; private: InputStream& inner; Array<byte> ownedBuffer; ArrayPtr<byte> buffer; ArrayPtr<byte> bufferAvailable; }; class BufferedOutputStreamWrapper: public BufferedOutputStream { // Implements BufferedOutputStream in terms of an OutputStream. Note that writes to the // underlying stream may be delayed until flush() is called or the wrapper is destroyed. public: explicit BufferedOutputStreamWrapper(OutputStream& inner, ArrayPtr<byte> buffer = nullptr); // Creates a buffered stream wrapping the given non-buffered stream. // // If the second parameter is non-null, the stream uses the given buffer instead of allocating // its own. This may improve performance if the buffer can be reused. KJ_DISALLOW_COPY(BufferedOutputStreamWrapper); ~BufferedOutputStreamWrapper() noexcept(false); void flush(); // Force the wrapper to write any remaining bytes in its buffer to the inner stream. Note that // this only flushes this object's buffer; this object has no idea how to flush any other buffers // that may be present in the underlying stream. // implements BufferedOutputStream --------------------------------- ArrayPtr<byte> getWriteBuffer() override; void write(const void* buffer, size_t size) override; private: OutputStream& inner; Array<byte> ownedBuffer; ArrayPtr<byte> buffer; byte* bufferPos; UnwindDetector unwindDetector; }; // ======================================================================================= // Array I/O class ArrayInputStream: public BufferedInputStream { public: explicit ArrayInputStream(ArrayPtr<const byte> array); KJ_DISALLOW_COPY(ArrayInputStream); ~ArrayInputStream() noexcept(false); // implements BufferedInputStream ---------------------------------- ArrayPtr<const byte> tryGetReadBuffer() override; size_t tryRead(void* buffer, size_t minBytes, size_t maxBytes) override; void skip(size_t bytes) override; private: ArrayPtr<const byte> array; }; class ArrayOutputStream: public BufferedOutputStream { public: explicit ArrayOutputStream(ArrayPtr<byte> array); KJ_DISALLOW_COPY(ArrayOutputStream); ~ArrayOutputStream() noexcept(false); ArrayPtr<byte> getArray() { // Get the portion of the array which has been filled in. return arrayPtr(array.begin(), fillPos); } // implements BufferedInputStream ---------------------------------- ArrayPtr<byte> getWriteBuffer() override; void write(const void* buffer, size_t size) override; private: ArrayPtr<byte> array; byte* fillPos; }; class VectorOutputStream: public BufferedOutputStream { public: explicit VectorOutputStream(size_t initialCapacity = 4096); KJ_DISALLOW_COPY(VectorOutputStream); ~VectorOutputStream() noexcept(false); ArrayPtr<byte> getArray() { // Get the portion of the array which has been filled in. return arrayPtr(vector.begin(), fillPos); } // implements BufferedInputStream ---------------------------------- ArrayPtr<byte> getWriteBuffer() override; void write(const void* buffer, size_t size) override; private: Array<byte> vector; byte* fillPos; void grow(size_t minSize); }; // ======================================================================================= // File descriptor I/O class AutoCloseFd { // A wrapper around a file descriptor which automatically closes the descriptor when destroyed. // The wrapper supports move construction for transferring ownership of the descriptor. If // close() returns an error, the destructor throws an exception, UNLESS the destructor is being // called during unwind from another exception, in which case the close error is ignored. // // If your code is not exception-safe, you should not use AutoCloseFd. In this case you will // have to call close() yourself and handle errors appropriately. public: inline AutoCloseFd(): fd(-1) {} inline AutoCloseFd(decltype(nullptr)): fd(-1) {} inline explicit AutoCloseFd(int fd): fd(fd) {} inline AutoCloseFd(AutoCloseFd&& other) noexcept: fd(other.fd) { other.fd = -1; } KJ_DISALLOW_COPY(AutoCloseFd); ~AutoCloseFd() noexcept(false); inline AutoCloseFd& operator=(AutoCloseFd&& other) { AutoCloseFd old(kj::mv(*this)); fd = other.fd; other.fd = -1; return *this; } inline AutoCloseFd& operator=(decltype(nullptr)) { AutoCloseFd old(kj::mv(*this)); return *this; } inline operator int() const { return fd; } inline int get() const { return fd; } operator bool() const = delete; // Deleting this operator prevents accidental use in boolean contexts, which // the int conversion operator above would otherwise allow. inline bool operator==(decltype(nullptr)) { return fd < 0; } inline bool operator!=(decltype(nullptr)) { return fd >= 0; } inline int release() { // Release ownership of an FD. Not recommended. int result = fd; fd = -1; return result; } private: int fd; }; inline auto KJ_STRINGIFY(const AutoCloseFd& fd) -> decltype(kj::toCharSequence(implicitCast<int>(fd))) { return kj::toCharSequence(implicitCast<int>(fd)); } class FdInputStream: public InputStream { // An InputStream wrapping a file descriptor. public: explicit FdInputStream(int fd): fd(fd) {} explicit FdInputStream(AutoCloseFd fd): fd(fd), autoclose(mv(fd)) {} KJ_DISALLOW_COPY(FdInputStream); ~FdInputStream() noexcept(false); size_t tryRead(void* buffer, size_t minBytes, size_t maxBytes) override; inline int getFd() const { return fd; } private: int fd; AutoCloseFd autoclose; }; class FdOutputStream: public OutputStream { // An OutputStream wrapping a file descriptor. public: explicit FdOutputStream(int fd): fd(fd) {} explicit FdOutputStream(AutoCloseFd fd): fd(fd), autoclose(mv(fd)) {} KJ_DISALLOW_COPY(FdOutputStream); ~FdOutputStream() noexcept(false); void write(const void* buffer, size_t size) override; void write(ArrayPtr<const ArrayPtr<const byte>> pieces) override; inline int getFd() const { return fd; } private: int fd; AutoCloseFd autoclose; }; // ======================================================================================= // Win32 Handle I/O #ifdef _WIN32 class AutoCloseHandle { // A wrapper around a Win32 HANDLE which automatically closes the handle when destroyed. // The wrapper supports move construction for transferring ownership of the handle. If // CloseHandle() returns an error, the destructor throws an exception, UNLESS the destructor is // being called during unwind from another exception, in which case the close error is ignored. // // If your code is not exception-safe, you should not use AutoCloseHandle. In this case you will // have to call close() yourself and handle errors appropriately. public: inline AutoCloseHandle(): handle((void*)-1) {} inline AutoCloseHandle(decltype(nullptr)): handle((void*)-1) {} inline explicit AutoCloseHandle(void* handle): handle(handle) {} inline AutoCloseHandle(AutoCloseHandle&& other) noexcept: handle(other.handle) { other.handle = (void*)-1; } KJ_DISALLOW_COPY(AutoCloseHandle); ~AutoCloseHandle() noexcept(false); inline AutoCloseHandle& operator=(AutoCloseHandle&& other) { AutoCloseHandle old(kj::mv(*this)); handle = other.handle; other.handle = (void*)-1; return *this; } inline AutoCloseHandle& operator=(decltype(nullptr)) { AutoCloseHandle old(kj::mv(*this)); return *this; } inline operator void*() const { return handle; } inline void* get() const { return handle; } operator bool() const = delete; // Deleting this operator prevents accidental use in boolean contexts, which // the void* conversion operator above would otherwise allow. inline bool operator==(decltype(nullptr)) { return handle != (void*)-1; } inline bool operator!=(decltype(nullptr)) { return handle == (void*)-1; } inline void* release() { // Release ownership of an FD. Not recommended. void* result = handle; handle = (void*)-1; return result; } private: void* handle; // -1 (aka INVALID_HANDLE_VALUE) if not valid. }; class HandleInputStream: public InputStream { // An InputStream wrapping a Win32 HANDLE. public: explicit HandleInputStream(void* handle): handle(handle) {} explicit HandleInputStream(AutoCloseHandle handle): handle(handle), autoclose(mv(handle)) {} KJ_DISALLOW_COPY(HandleInputStream); ~HandleInputStream() noexcept(false); size_t tryRead(void* buffer, size_t minBytes, size_t maxBytes) override; private: void* handle; AutoCloseHandle autoclose; }; class HandleOutputStream: public OutputStream { // An OutputStream wrapping a Win32 HANDLE. public: explicit HandleOutputStream(void* handle): handle(handle) {} explicit HandleOutputStream(AutoCloseHandle handle): handle(handle), autoclose(mv(handle)) {} KJ_DISALLOW_COPY(HandleOutputStream); ~HandleOutputStream() noexcept(false); void write(const void* buffer, size_t size) override; private: void* handle; AutoCloseHandle autoclose; }; #endif // _WIN32 } // namespace kj KJ_END_HEADER