From 5e72cadde80a2d9374b6324ed2467133de1fca69 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 8 Sep 2013 14:18:40 +0200 Subject: [PATCH] mingw: make the dirent implementation pluggable Emulating the POSIX `dirent` API on Windows via `FindFirstFile()`/`FindNextFile()` is pretty staightforward, however, most of the information provided in the `WIN32_FIND_DATA` structure is thrown away in the process. A more sophisticated implementation may cache this data, e.g. for later reuse in calls to `lstat()`. Make the `dirent` implementation pluggable so that it can be switched at runtime, e.g. based on a config option. Define a base DIR structure with pointers to `readdir()`/`closedir()` that match the `opendir()` implementation (similar to vtable pointers in Object-Oriented Programming). Define `readdir()`/`closedir()` so that they call the function pointers in the `DIR` structure. This allows to choose the `opendir()` implementation on a call-by-call basis. Make the fixed-size `dirent.d_name` buffer a flex array, as `d_name` may be implementation specific (e.g. a caching implementation may allocate a `struct dirent` with _just_ the size needed to hold the `d_name` in question). Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- compat/win32/dirent.c | 30 +++++++++++++++++++----------- compat/win32/dirent.h | 26 +++++++++++++++++++------- 2 files changed, 38 insertions(+), 18 deletions(-) diff --git a/compat/win32/dirent.c b/compat/win32/dirent.c index 2603a0fa39..139d2ba3c4 100644 --- a/compat/win32/dirent.c +++ b/compat/win32/dirent.c @@ -1,15 +1,21 @@ #include "../../git-compat-util.h" -struct DIR { - struct dirent dd_dir; /* includes d_type */ +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wpedantic" +typedef struct dirent_DIR { + struct DIR base_dir; /* extend base struct DIR */ HANDLE dd_handle; /* FindFirstFile handle */ int dd_stat; /* 0-based index */ -}; + struct dirent dd_dir; /* includes d_type */ +} dirent_DIR; +#pragma GCC diagnostic pop + +DIR *(*opendir)(const char *dirname) = dirent_opendir; static inline void finddata2dirent(struct dirent *ent, WIN32_FIND_DATAW *fdata) { - /* convert UTF-16 name to UTF-8 */ - xwcstoutf(ent->d_name, fdata->cFileName, sizeof(ent->d_name)); + /* convert UTF-16 name to UTF-8 (d_name points to dirent_DIR.dd_name) */ + xwcstoutf(ent->d_name, fdata->cFileName, MAX_PATH * 3); /* Set file type, based on WIN32_FIND_DATA */ if (fdata->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) @@ -18,7 +24,7 @@ static inline void finddata2dirent(struct dirent *ent, WIN32_FIND_DATAW *fdata) ent->d_type = DT_REG; } -struct dirent *readdir(DIR *dir) +static struct dirent *dirent_readdir(dirent_DIR *dir) { if (!dir) { errno = EBADF; /* No set_errno for mingw */ @@ -45,7 +51,7 @@ struct dirent *readdir(DIR *dir) return &dir->dd_dir; } -int closedir(DIR *dir) +static int dirent_closedir(dirent_DIR *dir) { if (!dir) { errno = EBADF; @@ -57,13 +63,13 @@ int closedir(DIR *dir) return 0; } -DIR *opendir(const char *name) +DIR *dirent_opendir(const char *name) { wchar_t pattern[MAX_PATH + 2]; /* + 2 for '/' '*' */ WIN32_FIND_DATAW fdata; HANDLE h; int len; - DIR *dir; + dirent_DIR *dir; /* convert name to UTF-16 and check length < MAX_PATH */ if ((len = xutftowcs_path(pattern, name)) < 0) @@ -84,9 +90,11 @@ DIR *opendir(const char *name) } /* initialize DIR structure and copy first dir entry */ - dir = xmalloc(sizeof(DIR)); + dir = xmalloc(sizeof(dirent_DIR) + MAX_PATH); + dir->base_dir.preaddir = (struct dirent *(*)(DIR *dir)) dirent_readdir; + dir->base_dir.pclosedir = (int (*)(DIR *dir)) dirent_closedir; dir->dd_handle = h; dir->dd_stat = 0; finddata2dirent(&dir->dd_dir, &fdata); - return dir; + return (DIR*) dir; } diff --git a/compat/win32/dirent.h b/compat/win32/dirent.h index 058207e4bf..e0e0e1700f 100644 --- a/compat/win32/dirent.h +++ b/compat/win32/dirent.h @@ -1,20 +1,32 @@ #ifndef DIRENT_H #define DIRENT_H -typedef struct DIR DIR; - #define DT_UNKNOWN 0 #define DT_DIR 1 #define DT_REG 2 #define DT_LNK 3 struct dirent { - unsigned char d_type; /* file type to prevent lstat after readdir */ - char d_name[MAX_PATH * 3]; /* file name (* 3 for UTF-8 conversion) */ + unsigned char d_type; /* file type to prevent lstat after readdir */ + char d_name[FLEX_ARRAY]; /* file name */ }; -DIR *opendir(const char *dirname); -struct dirent *readdir(DIR *dir); -int closedir(DIR *dir); +/* + * Base DIR structure, contains pointers to readdir/closedir implementations so + * that opendir may choose a concrete implementation on a call-by-call basis. + */ +typedef struct DIR { + struct dirent *(*preaddir)(struct DIR *dir); + int (*pclosedir)(struct DIR *dir); +} DIR; + +/* default dirent implementation */ +extern DIR *dirent_opendir(const char *dirname); + +/* current dirent implementation */ +extern DIR *(*opendir)(const char *dirname); + +#define readdir(dir) (dir->preaddir(dir)) +#define closedir(dir) (dir->pclosedir(dir)) #endif /* DIRENT_H */