#ifndef TEMPFILE_H
#define TEMPFILE_H
+#include "list.h"
+#include "strbuf.h"
+
/*
* Handle temporary files.
*
*
* The caller:
*
- * * Allocates a `struct tempfile` either as a static variable or on
- * the heap, initialized to zeros. Once you use the structure to
- * call `create_tempfile()`, it belongs to the tempfile subsystem
- * and its storage must remain valid throughout the life of the
- * program (i.e. you cannot use an on-stack variable to hold this
- * structure).
- *
* * Attempts to create a temporary file by calling
- * `create_tempfile()`.
+ * `create_tempfile()`. The resources used for the temporary file are
+ * managed by the tempfile API.
*
* * Writes new content to the file by either:
*
- * * writing to the file descriptor returned by `create_tempfile()`
- * (also available via `tempfile->fd`).
+ * * writing to the `tempfile->fd` file descriptor
*
* * calling `fdopen_tempfile()` to get a `FILE` pointer for the
* open file and writing to the file using stdio.
*
- * Note that the file descriptor returned by create_tempfile()
+ * Note that the file descriptor created by create_tempfile()
* is marked O_CLOEXEC, so the new contents must be written by
* the current process, not any spawned one.
*
* control of the file.
*
* * Close the file descriptor without removing or renaming the
- * temporary file by calling `close_tempfile()`, and later call
+ * temporary file by calling `close_tempfile_gently()`, and later call
* `delete_tempfile()` or `rename_tempfile()`.
*
- * Even after the temporary file is renamed or deleted, the `tempfile`
- * object must not be freed or altered by the caller. However, it may
- * be reused; just pass it to another call of `create_tempfile()`.
+ * After the temporary file is renamed or deleted, the `tempfile`
+ * object is no longer valid and should not be reused.
*
* If the program exits before `rename_tempfile()` or
* `delete_tempfile()` is called, an `atexit(3)` handler will close
* and remove the temporary file.
*
* If you need to close the file descriptor yourself, do so by calling
- * `close_tempfile()`. You should never call `close(2)` or `fclose(3)`
+ * `close_tempfile_gently()`. You should never call `close(2)` or `fclose(3)`
* yourself, otherwise the `struct tempfile` structure would still
* think that the file descriptor needs to be closed, and a later
* cleanup would result in duplicate calls to `close(2)`. Worse yet,
* Error handling
* --------------
*
- * `create_tempfile()` returns a file descriptor on success or -1 on
- * failure. On errors, `errno` describes the reason for failure.
+ * `create_tempfile()` returns an allocated tempfile on success or NULL
+ * on failure. On errors, `errno` describes the reason for failure.
*
- * `delete_tempfile()`, `rename_tempfile()`, and `close_tempfile()`
- * return 0 on success. On failure they set `errno` appropriately, do
- * their best to delete the temporary file, and return -1.
+ * `rename_tempfile()` and `close_tempfile_gently()` return 0 on success.
+ * On failure they set `errno` appropriately and return -1.
+ * `delete_tempfile()` and `rename` (but not `close`) do their best to
+ * delete the temporary file before returning.
*/
struct tempfile {
- struct tempfile *volatile next;
+ volatile struct volatile_list_head list;
volatile sig_atomic_t active;
volatile int fd;
FILE *volatile fp;
volatile pid_t owner;
- char on_list;
struct strbuf filename;
};
/*
* Attempt to create a temporary file at the specified `path`. Return
- * a file descriptor for writing to it, or -1 on error. It is an error
- * if a file already exists at that path.
+ * a tempfile (whose "fd" member can be used for writing to it), or
+ * NULL on error. It is an error if a file already exists at that path.
*/
-extern int create_tempfile(struct tempfile *tempfile, const char *path);
+extern struct tempfile *create_tempfile(const char *path);
/*
* Register an existing file as a tempfile, meaning that it will be
* but it can be worked with like any other closed tempfile (for
* example, it can be opened using reopen_tempfile()).
*/
-extern void register_tempfile(struct tempfile *tempfile, const char *path);
+extern struct tempfile *register_tempfile(const char *path);
/*
* know the (absolute) path of the file that was created, it can be
* read from tempfile->filename.
*
- * On success, the functions return a file descriptor that is open for
- * writing the temporary file. On errors, they return -1 and set errno
- * appropriately (except for the "x" variants, which die() on errors).
+ * On success, the functions return a tempfile whose "fd" member is open
+ * for writing the temporary file. On errors, they return NULL and set
+ * errno appropriately (except for the "x" variants, which die() on
+ * errors).
*/
/* See "mks_tempfile functions" above. */
-extern int mks_tempfile_sm(struct tempfile *tempfile,
- const char *template, int suffixlen, int mode);
+extern struct tempfile *mks_tempfile_sm(const char *filename_template,
+ int suffixlen, int mode);
/* See "mks_tempfile functions" above. */
-static inline int mks_tempfile_s(struct tempfile *tempfile,
- const char *template, int suffixlen)
+static inline struct tempfile *mks_tempfile_s(const char *filename_template,
+ int suffixlen)
{
- return mks_tempfile_sm(tempfile, template, suffixlen, 0600);
+ return mks_tempfile_sm(filename_template, suffixlen, 0600);
}
/* See "mks_tempfile functions" above. */
-static inline int mks_tempfile_m(struct tempfile *tempfile,
- const char *template, int mode)
+static inline struct tempfile *mks_tempfile_m(const char *filename_template, int mode)
{
- return mks_tempfile_sm(tempfile, template, 0, mode);
+ return mks_tempfile_sm(filename_template, 0, mode);
}
/* See "mks_tempfile functions" above. */
-static inline int mks_tempfile(struct tempfile *tempfile,
- const char *template)
+static inline struct tempfile *mks_tempfile(const char *filename_template)
{
- return mks_tempfile_sm(tempfile, template, 0, 0600);
+ return mks_tempfile_sm(filename_template, 0, 0600);
}
/* See "mks_tempfile functions" above. */
-extern int mks_tempfile_tsm(struct tempfile *tempfile,
- const char *template, int suffixlen, int mode);
+extern struct tempfile *mks_tempfile_tsm(const char *filename_template,
+ int suffixlen, int mode);
/* See "mks_tempfile functions" above. */
-static inline int mks_tempfile_ts(struct tempfile *tempfile,
- const char *template, int suffixlen)
+static inline struct tempfile *mks_tempfile_ts(const char *filename_template,
+ int suffixlen)
{
- return mks_tempfile_tsm(tempfile, template, suffixlen, 0600);
+ return mks_tempfile_tsm(filename_template, suffixlen, 0600);
}
/* See "mks_tempfile functions" above. */
-static inline int mks_tempfile_tm(struct tempfile *tempfile,
- const char *template, int mode)
+static inline struct tempfile *mks_tempfile_tm(const char *filename_template, int mode)
{
- return mks_tempfile_tsm(tempfile, template, 0, mode);
+ return mks_tempfile_tsm(filename_template, 0, mode);
}
/* See "mks_tempfile functions" above. */
-static inline int mks_tempfile_t(struct tempfile *tempfile,
- const char *template)
+static inline struct tempfile *mks_tempfile_t(const char *filename_template)
{
- return mks_tempfile_tsm(tempfile, template, 0, 0600);
+ return mks_tempfile_tsm(filename_template, 0, 0600);
}
/* See "mks_tempfile functions" above. */
-extern int xmks_tempfile_m(struct tempfile *tempfile,
- const char *template, int mode);
+extern struct tempfile *xmks_tempfile_m(const char *filename_template, int mode);
/* See "mks_tempfile functions" above. */
-static inline int xmks_tempfile(struct tempfile *tempfile,
- const char *template)
+static inline struct tempfile *xmks_tempfile(const char *filename_template)
{
- return xmks_tempfile_m(tempfile, template, 0600);
+ return xmks_tempfile_m(filename_template, 0600);
}
/*
* Associate a stdio stream with the temporary file (which must still
* be open). Return `NULL` (*without* deleting the file) on error. The
- * stream is closed automatically when `close_tempfile()` is called or
+ * stream is closed automatically when `close_tempfile_gently()` is called or
* when the file is deleted or renamed.
*/
extern FILE *fdopen_tempfile(struct tempfile *tempfile, const char *mode);
static inline int is_tempfile_active(struct tempfile *tempfile)
{
- return tempfile->active;
+ return tempfile && tempfile->active;
}
/*
* If the temporary file is still open, close it (and the file pointer
* too, if it has been opened using `fdopen_tempfile()`) without
* deleting the file. Return 0 upon success. On failure to `close(2)`,
- * return a negative value and delete the file. Usually
- * `delete_tempfile()` or `rename_tempfile()` should eventually be
- * called if `close_tempfile()` succeeds.
+ * return a negative value. Usually `delete_tempfile()` or `rename_tempfile()`
+ * should eventually be called regardless of whether `close_tempfile_gently()`
+ * succeeds.
*/
-extern int close_tempfile(struct tempfile *tempfile);
+extern int close_tempfile_gently(struct tempfile *tempfile);
/*
* Re-open a temporary file that has been closed using
- * `close_tempfile()` but not yet deleted or renamed. This can be used
+ * `close_tempfile_gently()` but not yet deleted or renamed. This can be used
* to implement a sequence of operations like the following:
*
* * Create temporary file.
*
- * * Write new contents to file, then `close_tempfile()` to cause the
+ * * Write new contents to file, then `close_tempfile_gently()` to cause the
* contents to be written to disk.
*
* * Pass the name of the temporary file to another program to allow
* it (and nobody else) to inspect or even modify the file's
* contents.
*
- * * `reopen_tempfile()` to reopen the temporary file. Make further
- * updates to the contents.
+ * * `reopen_tempfile()` to reopen the temporary file, truncating the existing
+ * contents. Write out the new contents.
*
* * `rename_tempfile()` to move the file to its permanent location.
*/
* `delete_tempfile()` for a `tempfile` object that has already been
* deleted or renamed.
*/
-extern void delete_tempfile(struct tempfile *tempfile);
+extern void delete_tempfile(struct tempfile **tempfile_p);
/*
* Close the file descriptor and/or file pointer if they are still
* `rename(2)`. It is a bug to call `rename_tempfile()` for a
* `tempfile` object that is not currently active.
*/
-extern int rename_tempfile(struct tempfile *tempfile, const char *path);
+extern int rename_tempfile(struct tempfile **tempfile_p, const char *path);
#endif /* TEMPFILE_H */
projects / platform / upstream / git.git / blobdiff