thodg/libgit2/src/fileops.h

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• Hash : 20e7f426
  Author :
  Date : 2009-01-03T00:36:10
  

  Add a simple mmap wrapper for cross-platform mmap usage Win32 has a variant of mmap that is harder to use than POSIX, but to run natively and efficiently on Win32 we need some form of it. gitfo_map_ro() provides a basic mmap function for use in locations where we need read-only random data access to large ranges of a file, such as a pack-*.idx. Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

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• src/fileops.h

• /*
   * fileops.h - OS agnostic disk io operations
   *
   * This header describes the strictly internal part of the api
   */
  #ifndef INCLUDE_fileops_h__
  #define INCLUDE_fileops_h__
  
  /** Force 64 bit off_t size on POSIX. */
  #define _FILE_OFFSET_BITS 64
  
  #include "common.h"
  #include <errno.h>
  #include <unistd.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <sys/types.h>
  #include <time.h>
  #include <stdlib.h>
  #include <string.h>
  #include <dirent.h>
  
  #define GITFO_BUF_INIT {NULL, 0}
  
  typedef int git_file;
  typedef struct gitfo_cache gitfo_cache;
  
  typedef struct {  /* file io buffer  */
  	void *data;  /* data bytes   */
  	size_t len;  /* data length  */
  } gitfo_buf;
  
  typedef struct {  /* memory mapped buffer */
  	void *data;   /* data bytes */
  	size_t len;   /* data length */
  } gitfo_map;
  
  extern int gitfo_exists(const char *path);
  extern int gitfo_open(const char *path, int flags);
  extern int gitfo_creat(const char *path, int mode);
  #define gitfo_close(fd) close(fd)
  
  extern int gitfo_read(git_file fd, void *buf, size_t cnt);
  extern int gitfo_write(git_file fd, void *buf, size_t cnt);
  extern off_t gitfo_size(git_file fd);
  
  extern int gitfo_read_file(gitfo_buf *obj, const char *path);
  extern void gitfo_free_buf(gitfo_buf *obj);
  
  /**
   * Read-only map all or part of a file into memory.
   * When possible this function should favor a virtual memory
   * style mapping over some form of malloc()+read(), as the
   * data access will be random and is not likely to touch the
   * majority of the region requested.
   *
   * @param out buffer to populate with the mapping information.
   * @param fd open descriptor to configure the mapping from.
   * @param begin first byte to map, this should be page aligned.
   * @param end number of bytes to map.
   * @return
   * - GIT_SUCCESS on success;
   * - GIT_EOSERR on an unspecified OS related error.
   */
  extern int gitfo_map_ro(
  	gitfo_map *out,
  	git_file fd,
  	off_t begin,
  	size_t len);
  
  /**
   * Release the memory associated with a previous memory mapping.
   * @param map the mapping description previously configured.
   */
  extern void gitfo_free_map(gitfo_map *map);
  
  /**
   * Walk each directory entry, except '.' and '..', calling fn(state).
   *
   * @param pathbuf buffer the function reads the initial directory
   * 		path from, and updates with each successive entry's name.
   * @param pathmax maximum allocation of pathbuf.
   * @param fn function to invoke with each entry.  The first arg is
   *		the input state and the second arg is pathbuf.  The function
   *		may modify the pathbuf, but only by appending new text.
   * @param state to pass to fn as the first arg.
   */
  extern int gitfo_dirent(
  	char *pathbuf,
  	size_t pathmax,
  	int (*fn)(void *, char *),
  	void *state);
  
  extern gitfo_cache *gitfo_enable_caching(git_file fd, size_t cache_size);
  extern int gitfo_write_cached(gitfo_cache *ioc, void *buf, size_t len);
  extern int gitfo_flush_cached(gitfo_cache *ioc);
  extern int gitfo_close_cached(gitfo_cache *ioc);
  
  #endif /* INCLUDE_fileops_h__ */
  

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