From 5c85e7024027c90b1b054782e510691b8b9c7419 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 28 Nov 2021 05:45:34 +0200 Subject: libcamera: base: Rename FileDescriptor to SharedFD Now that we have a UniqueFD class, the name FileDescriptor is ambiguous. Rename it to SharedFD. Signed-off-by: Laurent Pinchart Reviewed-by: Hirokazu Honda Reviewed-by: Jacopo Mondi --- src/libcamera/base/file.cpp | 1 + src/libcamera/base/file_descriptor.cpp | 266 --------------------------------- src/libcamera/base/meson.build | 2 +- src/libcamera/base/shared_fd.cpp | 262 ++++++++++++++++++++++++++++++++ 4 files changed, 264 insertions(+), 267 deletions(-) delete mode 100644 src/libcamera/base/file_descriptor.cpp create mode 100644 src/libcamera/base/shared_fd.cpp (limited to 'src/libcamera/base') diff --git a/src/libcamera/base/file.cpp b/src/libcamera/base/file.cpp index 923e03fa..fb3e276d 100644 --- a/src/libcamera/base/file.cpp +++ b/src/libcamera/base/file.cpp @@ -15,6 +15,7 @@ #include #include +#include /** * \file base/file.h diff --git a/src/libcamera/base/file_descriptor.cpp b/src/libcamera/base/file_descriptor.cpp deleted file mode 100644 index 8e181abc..00000000 --- a/src/libcamera/base/file_descriptor.cpp +++ /dev/null @@ -1,266 +0,0 @@ -/* SPDX-License-Identifier: LGPL-2.1-or-later */ -/* - * Copyright (C) 2019, Google Inc. - * - * file_descriptor.cpp - File descriptor wrapper - */ - -#include - -#include -#include -#include -#include - -#include -#include - -/** - * \file base/file_descriptor.h - * \brief File descriptor wrapper - */ - -namespace libcamera { - -LOG_DEFINE_CATEGORY(FileDescriptor) - -/** - * \class FileDescriptor - * \brief RAII-style wrapper for file descriptors - * - * The FileDescriptor class provides RAII-style lifetime management of file - * descriptors with an efficient mechanism for ownership sharing. At its core, - * an internal Descriptor object wraps a file descriptor (expressed as a signed - * integer) with an RAII-style interface. The Descriptor is then implicitly - * shared with all FileDescriptor instances constructed as copies. - * - * When constructed from a numerical file descriptor, the FileDescriptor - * instance either duplicates or takes over the file descriptor: - * - * - The FileDescriptor(const int &) constructor duplicates the numerical file - * descriptor and wraps the duplicate in a Descriptor. The caller is - * responsible for closing the original file descriptor, and the value - * returned by fd() will be different from the value passed to the - * constructor. - * - * - The FileDescriptor(int &&) constructor takes over the numerical file - * descriptor and wraps it in a Descriptor. The caller shall not touch the - * original file descriptor once the function returns, and the value returned - * by fd() will be identical to the value passed to the constructor. - * - * The copy constructor and assignment operator create copies that share the - * Descriptor, while the move versions of those functions additionally make the - * other FileDescriptor invalid. When the last FileDescriptor that references a - * Descriptor is destroyed, the file descriptor is closed. - * - * The numerical file descriptor is available through the fd() function. All - * FileDescriptor instances created as copies of a FileDescriptor will report - * the same fd() value. Callers can perform operations on the fd(), but shall - * never close it manually. - */ - -/** - * \brief Create a FileDescriptor copying a given \a fd - * \param[in] fd File descriptor - * - * Construct a FileDescriptor from a numerical file descriptor by duplicating - * the \a fd, and take ownership of the copy. The original \a fd is left - * untouched, and the caller is responsible for closing it when appropriate. - * The duplicated file descriptor will be closed automatically when all - * FileDescriptor instances that reference it are destroyed. - * - * If the \a fd is negative, the FileDescriptor is constructed as invalid and - * the fd() function will return -1. - */ -FileDescriptor::FileDescriptor(const int &fd) -{ - if (fd < 0) - return; - - fd_ = std::make_shared(fd, true); - if (fd_->fd() < 0) - fd_.reset(); -} - -/** - * \brief Create a FileDescriptor taking ownership of a given \a fd - * \param[in] fd File descriptor - * - * Construct a FileDescriptor from a numerical file descriptor by taking - * ownership of the \a fd. The original \a fd is set to -1 and shall not be - * touched by the caller anymore. In particular, the caller shall not close the - * original \a fd manually. The duplicated file descriptor will be closed - * automatically when all FileDescriptor instances that reference it are - * destroyed. - * - * If the \a fd is negative, the FileDescriptor is constructed as invalid and - * the fd() function will return -1. - */ -FileDescriptor::FileDescriptor(int &&fd) -{ - if (fd < 0) - return; - - fd_ = std::make_shared(fd, false); - /* - * The Descriptor constructor can't have failed here, as it took over - * the fd without duplicating it. Just set the original fd to -1 to - * implement move semantics. - */ - fd = -1; -} - -/** - * \brief Create a FileDescriptor taking ownership of a given UniqueFD \a fd - * \param[in] fd UniqueFD - * - * Construct a FileDescriptor from UniqueFD by taking ownership of the \a fd. - * The original \a fd becomes invalid. - */ -FileDescriptor::FileDescriptor(UniqueFD fd) - : FileDescriptor(fd.release()) -{ -} - -/** - * \brief Copy constructor, create a FileDescriptor from a copy of \a other - * \param[in] other The other FileDescriptor - * - * Copying a FileDescriptor implicitly shares ownership of the wrapped file - * descriptor. The original FileDescriptor is left untouched, and the caller is - * responsible for destroying it when appropriate. The wrapped file descriptor - * will be closed automatically when all FileDescriptor instances that - * reference it are destroyed. - */ -FileDescriptor::FileDescriptor(const FileDescriptor &other) - : fd_(other.fd_) -{ -} - -/** - * \brief Move constructor, create a FileDescriptor by taking over \a other - * \param[in] other The other FileDescriptor - * - * Moving a FileDescriptor moves the reference to the wrapped descriptor owned - * by \a other to the new FileDescriptor. The \a other FileDescriptor is - * invalidated and its fd() function will return -1. The wrapped file descriptor - * will be closed automatically when all FileDescriptor instances that - * reference it are destroyed. - */ -FileDescriptor::FileDescriptor(FileDescriptor &&other) - : fd_(std::move(other.fd_)) -{ -} - -/** - * \brief Destroy the FileDescriptor instance - * - * Destroying a FileDescriptor instance releases its reference to the wrapped - * descriptor, if any. When the last instance that references a wrapped - * descriptor is destroyed, the file descriptor is automatically closed. - */ -FileDescriptor::~FileDescriptor() -{ -} - -/** - * \brief Copy assignment operator, replace the wrapped file descriptor with a - * copy of \a other - * \param[in] other The other FileDescriptor - * - * Copying a FileDescriptor creates a new reference to the wrapped file - * descriptor owner by \a other. If \a other is invalid, *this will also be - * invalid. The original FileDescriptor is left untouched, and the caller is - * responsible for destroying it when appropriate. The wrapped file descriptor - * will be closed automatically when all FileDescriptor instances that - * reference it are destroyed. - * - * \return A reference to this FileDescriptor - */ -FileDescriptor &FileDescriptor::operator=(const FileDescriptor &other) -{ - fd_ = other.fd_; - - return *this; -} - -/** - * \brief Move assignment operator, replace the wrapped file descriptor by - * taking over \a other - * \param[in] other The other FileDescriptor - * - * Moving a FileDescriptor moves the reference to the wrapped descriptor owned - * by \a other to the new FileDescriptor. If \a other is invalid, *this will - * also be invalid. The \a other FileDescriptor is invalidated and its fd() - * function will return -1. The wrapped file descriptor will be closed - * automatically when all FileDescriptor instances that reference it are - * destroyed. - * - * \return A reference to this FileDescriptor - */ -FileDescriptor &FileDescriptor::operator=(FileDescriptor &&other) -{ - fd_ = std::move(other.fd_); - - return *this; -} - -/** - * \fn FileDescriptor::isValid() - * \brief Check if the FileDescriptor instance is valid - * \return True if the FileDescriptor is valid, false otherwise - */ - -/** - * \fn FileDescriptor::fd() - * \brief Retrieve the numerical file descriptor - * \return The numerical file descriptor, which may be -1 if the FileDescriptor - * instance is invalid - */ - -/** - * \brief Duplicate a FileDescriptor - * - * Duplicating a FileDescriptor creates a duplicate of the wrapped file - * descriptor and returns a UniqueFD that owns the duplicate. The fd() function - * of the original and the get() function of the duplicate will return different - * values. The duplicate instance will not be affected by destruction of the - * original instance or its copies. - * - * \return A UniqueFD owning a duplicate of the original file descriptor - */ -UniqueFD FileDescriptor::dup() const -{ - UniqueFD dupFd(::dup(fd())); - if (!dupFd.isValid()) { - int ret = -errno; - LOG(FileDescriptor, Error) - << "Failed to dup() fd: " << strerror(-ret); - } - - return dupFd; -} - -FileDescriptor::Descriptor::Descriptor(int fd, bool duplicate) -{ - if (!duplicate) { - fd_ = fd; - return; - } - - /* Failing to dup() a fd should not happen and is fatal. */ - fd_ = ::dup(fd); - if (fd_ == -1) { - int ret = -errno; - LOG(FileDescriptor, Fatal) - << "Failed to dup() fd: " << strerror(-ret); - } -} - -FileDescriptor::Descriptor::~Descriptor() -{ - if (fd_ != -1) - close(fd_); -} - -} /* namespace libcamera */ diff --git a/src/libcamera/base/meson.build b/src/libcamera/base/meson.build index 352ec6f0..0ae3b0aa 100644 --- a/src/libcamera/base/meson.build +++ b/src/libcamera/base/meson.build @@ -8,13 +8,13 @@ libcamera_base_sources = files([ 'event_dispatcher_poll.cpp', 'event_notifier.cpp', 'file.cpp', - 'file_descriptor.cpp', 'flags.cpp', 'log.cpp', 'message.cpp', 'mutex.cpp', 'object.cpp', 'semaphore.cpp', + 'shared_fd.cpp', 'signal.cpp', 'thread.cpp', 'timer.cpp', diff --git a/src/libcamera/base/shared_fd.cpp b/src/libcamera/base/shared_fd.cpp new file mode 100644 index 00000000..346b4a85 --- /dev/null +++ b/src/libcamera/base/shared_fd.cpp @@ -0,0 +1,262 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * shared_fd.cpp - File descriptor wrapper with shared ownership + */ + +#include + +#include +#include +#include +#include + +#include +#include + +/** + * \file base/shared_fd.h + * \brief File descriptor wrapper + */ + +namespace libcamera { + +LOG_DEFINE_CATEGORY(SharedFD) + +/** + * \class SharedFD + * \brief RAII-style wrapper for file descriptors + * + * The SharedFD class provides RAII-style lifetime management of file + * descriptors with an efficient mechanism for ownership sharing. At its core, + * an internal Descriptor object wraps a file descriptor (expressed as a signed + * integer) with an RAII-style interface. The Descriptor is then implicitly + * shared with all SharedFD instances constructed as copies. + * + * When constructed from a numerical file descriptor, the SharedFD instance + * either duplicates or takes over the file descriptor: + * + * - The SharedFD(const int &) constructor duplicates the numerical file + * descriptor and wraps the duplicate in a Descriptor. The caller is + * responsible for closing the original file descriptor, and the value + * returned by fd() will be different from the value passed to the + * constructor. + * + * - The SharedFD(int &&) constructor takes over the numerical file descriptor + * and wraps it in a Descriptor. The caller shall not touch the original file + * descriptor once the function returns, and the value returned by fd() will + * be identical to the value passed to the constructor. + * + * The copy constructor and assignment operator create copies that share the + * Descriptor, while the move versions of those functions additionally make the + * other SharedFD invalid. When the last SharedFD that references a Descriptor + * is destroyed, the file descriptor is closed. + * + * The numerical file descriptor is available through the fd() function. All + * SharedFD instances created as copies of a SharedFD will report the same fd() + * value. Callers can perform operations on the fd(), but shall never close it + * manually. + */ + +/** + * \brief Create a SharedFD copying a given \a fd + * \param[in] fd File descriptor + * + * Construct a SharedFD from a numerical file descriptor by duplicating the + * \a fd, and take ownership of the copy. The original \a fd is left untouched, + * and the caller is responsible for closing it when appropriate. The duplicated + * file descriptor will be closed automatically when all SharedFD instances that + * reference it are destroyed. + * + * If the \a fd is negative, the SharedFD is constructed as invalid and the fd() + * function will return -1. + */ +SharedFD::SharedFD(const int &fd) +{ + if (fd < 0) + return; + + fd_ = std::make_shared(fd, true); + if (fd_->fd() < 0) + fd_.reset(); +} + +/** + * \brief Create a SharedFD taking ownership of a given \a fd + * \param[in] fd File descriptor + * + * Construct a SharedFD from a numerical file descriptor by taking ownership of + * the \a fd. The original \a fd is set to -1 and shall not be touched by the + * caller anymore. In particular, the caller shall not close the original \a fd + * manually. The duplicated file descriptor will be closed automatically when + * all SharedFD instances that reference it are destroyed. + * + * If the \a fd is negative, the SharedFD is constructed as invalid and the fd() + * function will return -1. + */ +SharedFD::SharedFD(int &&fd) +{ + if (fd < 0) + return; + + fd_ = std::make_shared(fd, false); + /* + * The Descriptor constructor can't have failed here, as it took over + * the fd without duplicating it. Just set the original fd to -1 to + * implement move semantics. + */ + fd = -1; +} + +/** + * \brief Create a SharedFD taking ownership of a given UniqueFD \a fd + * \param[in] fd UniqueFD + * + * Construct a SharedFD from UniqueFD by taking ownership of the \a fd. The + * original \a fd becomes invalid. + */ +SharedFD::SharedFD(UniqueFD fd) + : SharedFD(fd.release()) +{ +} + +/** + * \brief Copy constructor, create a SharedFD from a copy of \a other + * \param[in] other The other SharedFD + * + * Copying a SharedFD implicitly shares ownership of the wrapped file + * descriptor. The original SharedFD is left untouched, and the caller is + * responsible for destroying it when appropriate. The wrapped file descriptor + * will be closed automatically when all SharedFD instances that reference it + * are destroyed. + */ +SharedFD::SharedFD(const SharedFD &other) + : fd_(other.fd_) +{ +} + +/** + * \brief Move constructor, create a SharedFD by taking over \a other + * \param[in] other The other SharedFD + * + * Moving a SharedFD moves the reference to the wrapped descriptor owned by + * \a other to the new SharedFD. The \a other SharedFD is invalidated and its + * fd() function will return -1. The wrapped file descriptor will be closed + * automatically when all SharedFD instances that reference it are destroyed. + */ +SharedFD::SharedFD(SharedFD &&other) + : fd_(std::move(other.fd_)) +{ +} + +/** + * \brief Destroy the SharedFD instance + * + * Destroying a SharedFD instance releases its reference to the wrapped + * descriptor, if any. When the last instance that references a wrapped + * descriptor is destroyed, the file descriptor is automatically closed. + */ +SharedFD::~SharedFD() +{ +} + +/** + * \brief Copy assignment operator, replace the wrapped file descriptor with a + * copy of \a other + * \param[in] other The other SharedFD + * + * Copying a SharedFD creates a new reference to the wrapped file descriptor + * owner by \a other. If \a other is invalid, *this will also be invalid. The + * original SharedFD is left untouched, and the caller is responsible for + * destroying it when appropriate. The wrapped file descriptor will be closed + * automatically when all SharedFD instances that reference it are destroyed. + * + * \return A reference to this SharedFD + */ +SharedFD &SharedFD::operator=(const SharedFD &other) +{ + fd_ = other.fd_; + + return *this; +} + +/** + * \brief Move assignment operator, replace the wrapped file descriptor by + * taking over \a other + * \param[in] other The other SharedFD + * + * Moving a SharedFD moves the reference to the wrapped descriptor owned by + * \a other to the new SharedFD. If \a other is invalid, *this will also be + * invalid. The \a other SharedFD is invalidated and its fd() function will + * return -1. The wrapped file descriptor will be closed automatically when + * all SharedFD instances that reference it are destroyed. + * + * \return A reference to this SharedFD + */ +SharedFD &SharedFD::operator=(SharedFD &&other) +{ + fd_ = std::move(other.fd_); + + return *this; +} + +/** + * \fn SharedFD::isValid() + * \brief Check if the SharedFD instance is valid + * \return True if the SharedFD is valid, false otherwise + */ + +/** + * \fn SharedFD::fd() + * \brief Retrieve the numerical file descriptor + * \return The numerical file descriptor, which may be -1 if the SharedFD + * instance is invalid + */ + +/** + * \brief Duplicate a SharedFD + * + * Duplicating a SharedFD creates a duplicate of the wrapped file descriptor and + * returns a UniqueFD that owns the duplicate. The fd() function of the original + * and the get() function of the duplicate will return different values. The + * duplicate instance will not be affected by destruction of the original + * instance or its copies. + * + * \return A UniqueFD owning a duplicate of the original file descriptor + */ +UniqueFD SharedFD::dup() const +{ + UniqueFD dupFd(::dup(fd())); + if (!dupFd.isValid()) { + int ret = -errno; + LOG(SharedFD, Error) + << "Failed to dup() fd: " << strerror(-ret); + } + + return dupFd; +} + +SharedFD::Descriptor::Descriptor(int fd, bool duplicate) +{ + if (!duplicate) { + fd_ = fd; + return; + } + + /* Failing to dup() a fd should not happen and is fatal. */ + fd_ = ::dup(fd); + if (fd_ == -1) { + int ret = -errno; + LOG(SharedFD, Fatal) + << "Failed to dup() fd: " << strerror(-ret); + } +} + +SharedFD::Descriptor::~Descriptor() +{ + if (fd_ != -1) + close(fd_); +} + +} /* namespace libcamera */ -- cgit v1.2.1