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transmission/libtransmission/file.h
Mike Gelfand b82f6009dd Maintain lock file(s) corresponding to session ID
2016-09-27 20:53:10 +03:00

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/*
* This file Copyright (C) 2013-2014 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#pragma once
#include <inttypes.h>
#include <time.h>
#ifdef _WIN32
#include <windows.h>
#endif
#ifdef __cplusplus
extern "C" {
#endif
struct tr_error;
/**
* @addtogroup file_io File IO
* @{
*/
#ifndef _WIN32
/** @brief Platform-specific file descriptor type. */
typedef int tr_sys_file_t;
/** @brief Platform-specific invalid file descriptor constant. */
#define TR_BAD_SYS_FILE (-1)
/** @brief Platform-specific directory descriptor type. */
typedef void * tr_sys_dir_t;
/** @brief Platform-specific end-of-line sequence. */
#define TR_NATIVE_EOL_STR "\n"
/** @brief Platform-specific end-of-line sequence length. */
#define TR_NATIVE_EOL_STR_SIZE 1
#else
typedef HANDLE tr_sys_file_t;
#define TR_BAD_SYS_FILE INVALID_HANDLE_VALUE
typedef struct tr_sys_dir_win32 * tr_sys_dir_t;
#define TR_NATIVE_EOL_STR "\r\n"
#define TR_NATIVE_EOL_STR_SIZE 2
#endif
/** @brief Platform-specific invalid directory descriptor constant. */
#define TR_BAD_SYS_DIR ((tr_sys_dir_t)NULL)
typedef enum
{
TR_STD_SYS_FILE_IN,
TR_STD_SYS_FILE_OUT,
TR_STD_SYS_FILE_ERR
}
tr_std_sys_file_t;
typedef enum
{
TR_SYS_FILE_READ = 1 << 0,
TR_SYS_FILE_WRITE = 1 << 1,
TR_SYS_FILE_CREATE = 1 << 2,
TR_SYS_FILE_CREATE_NEW = 1 << 3,
TR_SYS_FILE_APPEND = 1 << 4,
TR_SYS_FILE_TRUNCATE = 1 << 5,
TR_SYS_FILE_SEQUENTIAL = 1 << 6
}
tr_sys_file_open_flags_t;
typedef enum
{
TR_SEEK_SET,
TR_SEEK_CUR,
TR_SEEK_END
}
tr_seek_origin_t;
typedef enum
{
TR_SYS_FILE_LOCK_SH = 1 << 0,
TR_SYS_FILE_LOCK_EX = 1 << 1,
TR_SYS_FILE_LOCK_NB = 1 << 2,
TR_SYS_FILE_LOCK_UN = 1 << 3
}
tr_sys_file_lock_flags_t;
typedef enum
{
TR_SYS_PATH_NO_FOLLOW = 1 << 0
}
tr_sys_path_get_info_flags_t;
typedef enum
{
TR_SYS_FILE_PREALLOC_SPARSE = 1 << 0
}
tr_sys_file_preallocate_flags_t;
typedef enum
{
TR_SYS_DIR_CREATE_PARENTS = 1 << 0
}
tr_sys_dir_create_flags_t;
typedef enum
{
TR_SYS_PATH_IS_FILE,
TR_SYS_PATH_IS_DIRECTORY,
TR_SYS_PATH_IS_OTHER
}
tr_sys_path_type_t;
typedef struct tr_sys_path_info
{
tr_sys_path_type_t type;
uint64_t size;
time_t last_modified_at;
}
tr_sys_path_info;
/**
* @name Platform-specific wrapper functions
*
* Following functions accept paths in UTF-8 encoding and convert them to native
* encoding internally if needed.
* Descriptors returned (@ref tr_sys_file_t and @ref tr_sys_dir_t) may have
* different type depending on platform and should generally not be passed to
* native functions, but to wrapper functions instead.
*
* @{
*/
/* Path-related wrappers */
/**
* @brief Portability wrapper for `stat ()`.
*
* @param[in] path Path to file or directory.
* @param[in] flags Combination of @ref tr_sys_path_get_info_flags_t values.
* @param[out] info Result buffer.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_path_get_info (const char * path,
int flags,
tr_sys_path_info * info,
struct tr_error ** error);
/**
* @brief Portability wrapper for `access ()`.
*
* @param[in] path Path to file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` if path exists, `false` otherwise. Note that `false` will also
* be returned in case of error; if you need to distinguish the two,
* check if `error` is `NULL` afterwards.
*/
bool tr_sys_path_exists (const char * path,
struct tr_error ** error);
/**
* @brief Check whether path is relative.
*
* This function only analyzes the string, so no error reporting is needed.
*
* @param[in] path Path to file or directory.
*
* @return `True` if path is relative, `false` otherwise
*/
bool tr_sys_path_is_relative (const char * path);
/**
* @brief Test to see if the two filenames point to the same file.
*
* @param[in] path1 Path to first file or directory.
* @param[in] path2 Path to second file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` if two paths point to the same file or directory, `false`
* otherwise. Note that `false` will also be returned in case of error;
* if you need to distinguish the two, check if `error` is `NULL`
* afterwards.
*/
bool tr_sys_path_is_same (const char * path1,
const char * path2,
struct tr_error ** error);
/**
* @brief Portability wrapper for `realpath ()`.
*
* @param[in] path Path to file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Pointer to newly allocated buffer containing full path (with symbolic
* links, `.` and `..` resolved) on success (use @ref tr_free to free it
* when no longer needed), `NULL` otherwise (with `error` set
* accordingly).
*/
char * tr_sys_path_resolve (const char * path,
struct tr_error ** error);
/**
* @brief Portability wrapper for `basename ()`.
*
* @param[in] path Path to file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Pointer to newly allocated buffer containing base name (last path
* component; parent path removed) on success (use @ref tr_free to free
* it when no longer needed), `NULL` otherwise (with `error` set
* accordingly).
*/
char * tr_sys_path_basename (const char * path,
struct tr_error ** error);
/**
* @brief Portability wrapper for `dirname ()`.
*
* @param[in] path Path to file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Pointer to newly allocated buffer containing directory (parent path;
* last path component removed) on success (use @ref tr_free to free it
* when no longer needed), `NULL` otherwise (with `error` set
* accordingly).
*/
char * tr_sys_path_dirname (const char * path,
struct tr_error ** error);
/**
* @brief Portability wrapper for `rename ()`.
*
* @param[in] src_path Path to source file or directory.
* @param[in] dst_path Path to destination file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
* Rename will generally only succeed if both source and destination are
* on the same partition.
*/
bool tr_sys_path_rename (const char * src_path,
const char * dst_path,
struct tr_error ** error);
/**
* @brief Portability wrapper for `remove ()`.
*
* @param[in] path Path to file or directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
* Directory removal will only succeed if it is empty (contains no other
* files and directories).
*/
bool tr_sys_path_remove (const char * path,
struct tr_error ** error);
/* File-related wrappers */
/**
* @brief Get handle to one of standard I/O files.
*
* @param[in] std_file Standard file identifier.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return Opened file descriptor on success, `TR_BAD_SYS_FILE` otherwise (with
* `error` set accordingly). DO NOT pass this descriptor to
* @ref tr_sys_file_close (unless you know what you are doing).
*/
tr_sys_file_t tr_sys_file_get_std (tr_std_sys_file_t std_file,
struct tr_error ** error);
/**
* @brief Portability wrapper for `open ()`.
*
* @param[in] path Path to file.
* @param[in] flags Combination of @ref tr_sys_file_open_flags_t values.
* @param[in] permissions Permissions to create file with (in case
@ref TR_SYS_FILE_CREATE is used). Not used on Windows.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return Opened file descriptor on success, `TR_BAD_SYS_FILE` otherwise (with
* `error` set accordingly).
*/
tr_sys_file_t tr_sys_file_open (const char * path,
int flags,
int permissions,
struct tr_error ** error);
/**
* @brief Portability wrapper for `mkstemp ()`.
*
* @param[in,out] path_template Template path to file. Should end with at least
* six 'X' characters. Upon success, trailing 'X'
* characters are replaced with actual random
* characters used to form a unique path to
* temporary file.
* @param[out] error Pointer to error object. Optional, pass `NULL`
* if you are not interested in error details.
*
* @return Opened file descriptor on success, `TR_BAD_SYS_FILE` otherwise (with
* `error` set accordingly).
*/
tr_sys_file_t tr_sys_file_open_temp (char * path_template,
struct tr_error ** error);
/**
* @brief Portability wrapper for `close ()`.
*
* @param[in] handle Valid file descriptor.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_close (tr_sys_file_t handle,
struct tr_error ** error);
/**
* @brief Portability wrapper for `fstat ()`.
*
* @param[in] handle Valid file descriptor.
* @param[out] info Result buffer.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_get_info (tr_sys_file_t handle,
tr_sys_path_info * info,
struct tr_error ** error);
/**
* @brief Portability wrapper for `lseek ()`.
*
* @param[in] handle Valid file descriptor.
* @param[in] offset Relative file offset in bytes to seek to.
* @param[in] origin Offset origin.
* @param[out] new_offset New offset in bytes from beginning of file. Optional,
* pass `NULL` if you are not interested.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_seek (tr_sys_file_t handle,
int64_t offset,
tr_seek_origin_t origin,
uint64_t * new_offset,
struct tr_error ** error);
/**
* @brief Portability wrapper for `read ()`.
*
* @param[in] handle Valid file descriptor.
* @param[out] buffer Buffer to store read data to.
* @param[in] size Number of bytes to read.
* @param[out] bytes_read Number of bytes actually read. Optional, pass `NULL`
* if you are not interested.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_read (tr_sys_file_t handle,
void * buffer,
uint64_t size,
uint64_t * bytes_read,
struct tr_error ** error);
/**
* @brief Like `pread ()`, except that the position is undefined afterwards.
* Not thread-safe.
*
* @param[in] handle Valid file descriptor.
* @param[out] buffer Buffer to store read data to.
* @param[in] size Number of bytes to read.
* @param[in] offset File offset in bytes to start reading from.
* @param[out] bytes_read Number of bytes actually read. Optional, pass `NULL`
* if you are not interested.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_read_at (tr_sys_file_t handle,
void * buffer,
uint64_t size,
uint64_t offset,
uint64_t * bytes_read,
struct tr_error ** error);
/**
* @brief Portability wrapper for `write ()`.
*
* @param[in] handle Valid file descriptor.
* @param[in] buffer Buffer to get data being written from.
* @param[in] size Number of bytes to write.
* @param[out] bytes_written Number of bytes actually written. Optional, pass
* `NULL` if you are not interested.
* @param[out] error Pointer to error object. Optional, pass `NULL` if
* you are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_write (tr_sys_file_t handle,
const void * buffer,
uint64_t size,
uint64_t * bytes_written,
struct tr_error ** error);
/**
* @brief Like `pwrite ()`, except that the position is undefined afterwards.
* Not thread-safe.
*
* @param[in] handle Valid file descriptor.
* @param[in] buffer Buffer to get data being written from.
* @param[in] size Number of bytes to write.
* @param[in] offset File offset in bytes to start writing from.
* @param[out] bytes_written Number of bytes actually written. Optional, pass
* `NULL` if you are not interested.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_write_at (tr_sys_file_t handle,
const void * buffer,
uint64_t size,
uint64_t offset,
uint64_t * bytes_written,
struct tr_error ** error);
/**
* @brief Portability wrapper for `fsync ()`.
*
* @param[in] handle Valid file descriptor.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_flush (tr_sys_file_t handle,
struct tr_error ** error);
/**
* @brief Portability wrapper for `ftruncate ()`.
*
* @param[in] handle Valid file descriptor.
* @param[in] size Number of bytes to truncate (or extend) file to.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_truncate (tr_sys_file_t handle,
uint64_t size,
struct tr_error ** error);
/**
* @brief Tell system to prefetch some part of file which is to be read soon.
*
* @param[in] handle Valid file descriptor.
* @param[in] offset Offset in file to prefetch from.
* @param[in] size Number of bytes to prefetch.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_prefetch (tr_sys_file_t handle,
uint64_t offset,
uint64_t size,
struct tr_error ** error);
/**
* @brief Preallocate file to specified size in full or sparse mode.
*
* @param[in] handle Valid file descriptor.
* @param[in] size Number of bytes to preallocate file to.
* @param[in] flags Combination of @ref tr_sys_file_preallocate_flags_t values.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_preallocate (tr_sys_file_t handle,
uint64_t size,
int flags,
struct tr_error ** error);
/**
* @brief Portability wrapper for `mmap ()` for files.
*
* @param[in] handle Valid file descriptor.
* @param[in] offset Offset in file to map from.
* @param[in] size Number of bytes to map.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Pointer to mapped file data on success, `NULL` otherwise (with
* `error` set accordingly).
*/
void * tr_sys_file_map_for_reading (tr_sys_file_t handle,
uint64_t offset,
uint64_t size,
struct tr_error ** error);
/**
* @brief Portability wrapper for `munmap ()` for files.
*
* @param[in] address Pointer to mapped file data.
* @param[in] size Size of mapped data in bytes.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_unmap (const void * address,
uint64_t size,
struct tr_error ** error);
/**
* @brief Portability wrapper for `flock ()`.
*
* Don't try to upgrade or downgrade the lock unless you know what you are
* doing, as behavior varies a bit between platforms.
*
* @param[in] handle Valid file descriptor.
* @param[in] operation Combination of @ref tr_sys_file_lock_flags_t values.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_lock (tr_sys_file_t handle,
int operation,
struct tr_error ** error);
/* File-related wrappers (utility) */
/**
* @brief Portability wrapper for `fgets ()`, removing EOL internally.
*
* Special care should be taken when reading from one of standard input streams
* (@ref tr_std_sys_file_t) since no UTF-8 conversion is currently being made.
*
* Reading from other streams (files, pipes) also leaves data untouched, so it
* should already be in UTF-8 encoding, or whichever else you expect.
*
* @param[in] handle Valid file descriptor.
* @param[out] buffer Buffer to store read zero-terminated string to.
* @param[in] buffer_size Buffer size in bytes, taking '\0' character into
* account.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
* Note that `false` will also be returned in case of end of file; if
* you need to distinguish the two, check if `error` is `NULL`
* afterwards.
*/
bool tr_sys_file_read_line (tr_sys_file_t handle,
char * buffer,
size_t buffer_size,
struct tr_error ** error);
/**
* @brief Portability wrapper for `fputs ()`, appending EOL internally.
*
* Special care should be taken when writing to one of standard output streams
* (@ref tr_std_sys_file_t) since no UTF-8 conversion is currently being made.
*
* Writing to other streams (files, pipes) also leaves data untouched, so it
* should already be in UTF-8 encoding, or whichever else you expect.
*
* @param[in] handle Valid file descriptor.
* @param[in] buffer Zero-terminated string to write.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_write_line (tr_sys_file_t handle,
const char * buffer,
struct tr_error ** error);
/**
* @brief Portability wrapper for `fprintf ()`.
*
* Special care should be taken when writing to one of standard output streams
* (@ref tr_std_sys_file_t) since no UTF-8 conversion is currently being made.
*
* Writing to other streams (files, pipes) also leaves data untouched, so it
* should already be in UTF-8 encoding, or whichever else you expect.
*
* @param[in] handle Valid file descriptor.
* @param[in] format String format to write.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
* @param[in] ... Format arguments.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_file_write_fmt (tr_sys_file_t handle,
const char * format,
struct tr_error ** error,
...);
/* Directory-related wrappers */
/**
* @brief Portability wrapper for `getcwd ()`.
*
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Pointer to newly allocated buffer containing path to current
* directory (use @ref tr_free to free it when no longer needed) on
* success, `NULL` otherwise (with `error` set accordingly).
*/
char * tr_sys_dir_get_current (struct tr_error ** error);
/**
* @brief Like `mkdir ()`, but makes parent directories if needed.
*
* @param[in] path Path to directory.
* @param[in] flags Combination of @ref tr_sys_dir_create_flags_t values.
* @param[in] permissions Permissions to create directory with. Not used on
Windows.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you
* are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_dir_create (const char * path,
int flags,
int permissions,
struct tr_error ** error);
/**
* @brief Portability wrapper for `mkdtemp ()`.
*
* @param[in,out] path_template Template path to directory. Should end with at
* least six 'X' characters. Upon success, trailing
* 'X' characters are replaced with actual random
* characters used to form a unique path to
* temporary directory.
* @param[out] error Pointer to error object. Optional, pass `NULL`
* if you are not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_dir_create_temp (char * path_template,
struct tr_error ** error);
/**
* @brief Portability wrapper for `opendir ()`.
*
* @param[in] path Path to directory.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Opened directory descriptor on success, `TR_BAD_SYS_DIR` otherwise
* (with `error` set accordingly).
*/
tr_sys_dir_t tr_sys_dir_open (const char * path,
struct tr_error ** error);
/**
* @brief Portability wrapper for `readdir ()`.
*
* @param[in] handle Valid directory descriptor.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return Pointer to next directory entry name (stored internally, DO NOT pass
* it to @ref tr_free) on success, `NULL` otherwise (with `error` set
* accordingly). Note that `NULL` will also be returned in case of end
* of directory; if you need to distinguish the two, check if `error`
* is `NULL` afterwards.
*/
const char * tr_sys_dir_read_name (tr_sys_dir_t handle,
struct tr_error ** error);
/**
* @brief Portability wrapper for `closedir ()`.
*
* @param[in] handle Valid directory descriptor.
* @param[out] error Pointer to error object. Optional, pass `NULL` if you are
* not interested in error details.
*
* @return `True` on success, `false` otherwise (with `error` set accordingly).
*/
bool tr_sys_dir_close (tr_sys_dir_t handle,
struct tr_error ** error);
/** @} */
/** @} */
#ifdef __cplusplus
}
#endif
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