8c25e4bb59ecaee2da936e6ab86cc16b07979444
[git.git] / strbuf.h
blob8c25e4bb59ecaee2da936e6ab86cc16b07979444
1 #ifndef STRBUF_H
2 #define STRBUF_H
4 /**
5 * strbuf's are meant to be used with all the usual C string and memory
6 * APIs. Given that the length of the buffer is known, it's often better to
7 * use the mem* functions than a str* one (memchr vs. strchr e.g.).
8 * Though, one has to be careful about the fact that str* functions often
9 * stop on NULs and that strbufs may have embedded NULs.
11 * A strbuf is NUL terminated for convenience, but no function in the
12 * strbuf API actually relies on the string being free of NULs.
14 * strbufs have some invariants that are very important to keep in mind:
16 * - The `buf` member is never NULL, so it can be used in any usual C
17 * string operations safely. strbuf's _have_ to be initialized either by
18 * `strbuf_init()` or by `= STRBUF_INIT` before the invariants, though.
20 * Do *not* assume anything on what `buf` really is (e.g. if it is
21 * allocated memory or not), use `strbuf_detach()` to unwrap a memory
22 * buffer from its strbuf shell in a safe way. That is the sole supported
23 * way. This will give you a malloced buffer that you can later `free()`.
25 * However, it is totally safe to modify anything in the string pointed by
26 * the `buf` member, between the indices `0` and `len-1` (inclusive).
28 * - The `buf` member is a byte array that has at least `len + 1` bytes
29 * allocated. The extra byte is used to store a `'\0'`, allowing the
30 * `buf` member to be a valid C-string. Every strbuf function ensure this
31 * invariant is preserved.
33 * NOTE: It is OK to "play" with the buffer directly if you work it this
34 * way:
36 * strbuf_grow(sb, SOME_SIZE); <1>
37 * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
39 * <1> Here, the memory array starting at `sb->buf`, and of length
40 * `strbuf_avail(sb)` is all yours, and you can be sure that
41 * `strbuf_avail(sb)` is at least `SOME_SIZE`.
43 * NOTE: `SOME_OTHER_SIZE` must be smaller or equal to `strbuf_avail(sb)`.
45 * Doing so is safe, though if it has to be done in many places, adding the
46 * missing API to the strbuf module is the way to go.
48 * WARNING: Do _not_ assume that the area that is yours is of size `alloc
49 * - 1` even if it's true in the current implementation. Alloc is somehow a
50 * "private" member that should not be messed with. Use `strbuf_avail()`
51 * instead.
54 /**
55 * Data Structures
56 * ---------------
59 /**
60 * This is the string buffer structure. The `len` member can be used to
61 * determine the current length of the string, and `buf` member provides
62 * access to the string itself.
64 struct strbuf {
65 size_t alloc;
66 size_t len;
67 char *buf;
70 extern char strbuf_slopbuf[];
71 #define STRBUF_INIT { .alloc = 0, .len = 0, .buf = strbuf_slopbuf }
74 * Predeclare this here, since cache.h includes this file before it defines the
75 * struct.
77 struct object_id;
79 /**
80 * Life Cycle Functions
81 * --------------------
84 /**
85 * Initialize the structure. The second parameter can be zero or a bigger
86 * number to allocate memory, in case you want to prevent further reallocs.
88 extern void strbuf_init(struct strbuf *, size_t);
90 /**
91 * Release a string buffer and the memory it used. After this call, the
92 * strbuf points to an empty string that does not need to be free()ed, as
93 * if it had been set to `STRBUF_INIT` and never modified.
95 * To clear a strbuf in preparation for further use without the overhead
96 * of free()ing and malloc()ing again, use strbuf_reset() instead.
98 extern void strbuf_release(struct strbuf *);
101 * Detach the string from the strbuf and returns it; you now own the
102 * storage the string occupies and it is your responsibility from then on
103 * to release it with `free(3)` when you are done with it.
105 * The strbuf that previously held the string is reset to `STRBUF_INIT` so
106 * it can be reused after calling this function.
108 extern char *strbuf_detach(struct strbuf *, size_t *);
111 * Attach a string to a buffer. You should specify the string to attach,
112 * the current length of the string and the amount of allocated memory.
113 * The amount must be larger than the string length, because the string you
114 * pass is supposed to be a NUL-terminated string. This string _must_ be
115 * malloc()ed, and after attaching, the pointer cannot be relied upon
116 * anymore, and neither be free()d directly.
118 extern void strbuf_attach(struct strbuf *, void *, size_t, size_t);
121 * Swap the contents of two string buffers.
123 static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
125 SWAP(*a, *b);
130 * Functions related to the size of the buffer
131 * -------------------------------------------
135 * Determine the amount of allocated but unused memory.
137 static inline size_t strbuf_avail(const struct strbuf *sb)
139 return sb->alloc ? sb->alloc - sb->len - 1 : 0;
143 * Ensure that at least this amount of unused memory is available after
144 * `len`. This is used when you know a typical size for what you will add
145 * and want to avoid repetitive automatic resizing of the underlying buffer.
146 * This is never a needed operation, but can be critical for performance in
147 * some cases.
149 extern void strbuf_grow(struct strbuf *, size_t);
152 * Set the length of the buffer to a given value. This function does *not*
153 * allocate new memory, so you should not perform a `strbuf_setlen()` to a
154 * length that is larger than `len + strbuf_avail()`. `strbuf_setlen()` is
155 * just meant as a 'please fix invariants from this strbuf I just messed
156 * with'.
158 static inline void strbuf_setlen(struct strbuf *sb, size_t len)
160 if (len > (sb->alloc ? sb->alloc - 1 : 0))
161 die("BUG: strbuf_setlen() beyond buffer");
162 sb->len = len;
163 if (sb->buf != strbuf_slopbuf)
164 sb->buf[len] = '\0';
165 else
166 assert(!strbuf_slopbuf[0]);
170 * Empty the buffer by setting the size of it to zero.
172 #define strbuf_reset(sb) strbuf_setlen(sb, 0)
176 * Functions related to the contents of the buffer
177 * -----------------------------------------------
181 * Strip whitespace from the beginning (`ltrim`), end (`rtrim`), or both side
182 * (`trim`) of a string.
184 extern void strbuf_trim(struct strbuf *);
185 extern void strbuf_rtrim(struct strbuf *);
186 extern void strbuf_ltrim(struct strbuf *);
188 /* Strip trailing directory separators */
189 extern void strbuf_trim_trailing_dir_sep(struct strbuf *);
192 * Replace the contents of the strbuf with a reencoded form. Returns -1
193 * on error, 0 on success.
195 extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
198 * Lowercase each character in the buffer using `tolower`.
200 extern void strbuf_tolower(struct strbuf *sb);
203 * Compare two buffers. Returns an integer less than, equal to, or greater
204 * than zero if the first buffer is found, respectively, to be less than,
205 * to match, or be greater than the second buffer.
207 extern int strbuf_cmp(const struct strbuf *, const struct strbuf *);
211 * Adding data to the buffer
212 * -------------------------
214 * NOTE: All of the functions in this section will grow the buffer as
215 * necessary. If they fail for some reason other than memory shortage and the
216 * buffer hadn't been allocated before (i.e. the `struct strbuf` was set to
217 * `STRBUF_INIT`), then they will free() it.
221 * Add a single character to the buffer.
223 static inline void strbuf_addch(struct strbuf *sb, int c)
225 if (!strbuf_avail(sb))
226 strbuf_grow(sb, 1);
227 sb->buf[sb->len++] = c;
228 sb->buf[sb->len] = '\0';
232 * Add a character the specified number of times to the buffer.
234 extern void strbuf_addchars(struct strbuf *sb, int c, size_t n);
237 * Insert data to the given position of the buffer. The remaining contents
238 * will be shifted, not overwritten.
240 extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
243 * Remove given amount of data from a given position of the buffer.
245 extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
248 * Remove the bytes between `pos..pos+len` and replace it with the given
249 * data.
251 extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
252 const void *, size_t);
255 * Add a NUL-terminated string to the buffer. Each line will be prepended
256 * by a comment character and a blank.
258 extern void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size);
262 * Add data of given length to the buffer.
264 extern void strbuf_add(struct strbuf *, const void *, size_t);
267 * Add a NUL-terminated string to the buffer.
269 * NOTE: This function will *always* be implemented as an inline or a macro
270 * using strlen, meaning that this is efficient to write things like:
272 * strbuf_addstr(sb, "immediate string");
275 static inline void strbuf_addstr(struct strbuf *sb, const char *s)
277 strbuf_add(sb, s, strlen(s));
281 * Copy the contents of another buffer at the end of the current one.
283 extern void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2);
286 * This function can be used to expand a format string containing
287 * placeholders. To that end, it parses the string and calls the specified
288 * function for every percent sign found.
290 * The callback function is given a pointer to the character after the `%`
291 * and a pointer to the struct strbuf. It is expected to add the expanded
292 * version of the placeholder to the strbuf, e.g. to add a newline
293 * character if the letter `n` appears after a `%`. The function returns
294 * the length of the placeholder recognized and `strbuf_expand()` skips
295 * over it.
297 * The format `%%` is automatically expanded to a single `%` as a quoting
298 * mechanism; callers do not need to handle the `%` placeholder themselves,
299 * and the callback function will not be invoked for this placeholder.
301 * All other characters (non-percent and not skipped ones) are copied
302 * verbatim to the strbuf. If the callback returned zero, meaning that the
303 * placeholder is unknown, then the percent sign is copied, too.
305 * In order to facilitate caching and to make it possible to give
306 * parameters to the callback, `strbuf_expand()` passes a context pointer,
307 * which can be used by the programmer of the callback as she sees fit.
309 typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);
310 extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);
313 * Used as callback for `strbuf_expand()`, expects an array of
314 * struct strbuf_expand_dict_entry as context, i.e. pairs of
315 * placeholder and replacement string. The array needs to be
316 * terminated by an entry with placeholder set to NULL.
318 struct strbuf_expand_dict_entry {
319 const char *placeholder;
320 const char *value;
322 extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);
325 * Append the contents of one strbuf to another, quoting any
326 * percent signs ("%") into double-percents ("%%") in the
327 * destination. This is useful for literal data to be fed to either
328 * strbuf_expand or to the *printf family of functions.
330 extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
333 * Append the given byte size as a human-readable string (i.e. 12.23 KiB,
334 * 3.50 MiB).
336 extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
339 * Add a formatted string to the buffer.
341 __attribute__((format (printf,2,3)))
342 extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
345 * Add a formatted string prepended by a comment character and a
346 * blank to the buffer.
348 __attribute__((format (printf, 2, 3)))
349 extern void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...);
351 __attribute__((format (printf,2,0)))
352 extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
355 * Add the time specified by `tm`, as formatted by `strftime`.
356 * `tz_offset` is in decimal hhmm format, e.g. -600 means six hours west
357 * of Greenwich, and it's used to expand %z internally. However, tokens
358 * with modifiers (e.g. %Ez) are passed to `strftime`.
359 * `suppress_tz_name`, when set, expands %Z internally to the empty
360 * string rather than passing it to `strftime`.
362 extern void strbuf_addftime(struct strbuf *sb, const char *fmt,
363 const struct tm *tm, int tz_offset,
364 int suppress_tz_name);
367 * Read a given size of data from a FILE* pointer to the buffer.
369 * NOTE: The buffer is rewound if the read fails. If -1 is returned,
370 * `errno` must be consulted, like you would do for `read(3)`.
371 * `strbuf_read()`, `strbuf_read_file()` and `strbuf_getline_*()`
372 * family of functions have the same behaviour as well.
374 extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
377 * Read the contents of a given file descriptor. The third argument can be
378 * used to give a hint about the file size, to avoid reallocs. If read fails,
379 * any partial read is undone.
381 extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
384 * Read the contents of a given file descriptor partially by using only one
385 * attempt of xread. The third argument can be used to give a hint about the
386 * file size, to avoid reallocs. Returns the number of new bytes appended to
387 * the sb.
389 extern ssize_t strbuf_read_once(struct strbuf *, int fd, size_t hint);
392 * Read the contents of a file, specified by its path. The third argument
393 * can be used to give a hint about the file size, to avoid reallocs.
394 * Return the number of bytes read or a negative value if some error
395 * occurred while opening or reading the file.
397 extern ssize_t strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
400 * Read the target of a symbolic link, specified by its path. The third
401 * argument can be used to give a hint about the size, to avoid reallocs.
403 extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
406 * Write the whole content of the strbuf to the stream not stopping at
407 * NUL bytes.
409 extern ssize_t strbuf_write(struct strbuf *sb, FILE *stream);
412 * Read a line from a FILE *, overwriting the existing contents of
413 * the strbuf. The strbuf_getline*() family of functions share
414 * this signature, but have different line termination conventions.
416 * Reading stops after the terminator or at EOF. The terminator
417 * is removed from the buffer before returning. Returns 0 unless
418 * there was nothing left before EOF, in which case it returns `EOF`.
420 typedef int (*strbuf_getline_fn)(struct strbuf *, FILE *);
422 /* Uses LF as the line terminator */
423 extern int strbuf_getline_lf(struct strbuf *sb, FILE *fp);
425 /* Uses NUL as the line terminator */
426 extern int strbuf_getline_nul(struct strbuf *sb, FILE *fp);
429 * Similar to strbuf_getline_lf(), but additionally treats a CR that
430 * comes immediately before the LF as part of the terminator.
431 * This is the most friendly version to be used to read "text" files
432 * that can come from platforms whose native text format is CRLF
433 * terminated.
435 extern int strbuf_getline(struct strbuf *, FILE *);
439 * Like `strbuf_getline`, but keeps the trailing terminator (if
440 * any) in the buffer.
442 extern int strbuf_getwholeline(struct strbuf *, FILE *, int);
445 * Like `strbuf_getwholeline`, but operates on a file descriptor.
446 * It reads one character at a time, so it is very slow. Do not
447 * use it unless you need the correct position in the file
448 * descriptor.
450 extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
453 * Set the buffer to the path of the current working directory.
455 extern int strbuf_getcwd(struct strbuf *sb);
458 * Add a path to a buffer, converting a relative path to an
459 * absolute one in the process. Symbolic links are not
460 * resolved.
462 extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
465 * Canonize `path` (make it absolute, resolve symlinks, remove extra
466 * slashes) and append it to `sb`. Die with an informative error
467 * message if there is a problem.
469 * The directory part of `path` (i.e., everything up to the last
470 * dir_sep) must denote a valid, existing directory, but the last
471 * component need not exist.
473 * Callers that don't mind links should use the more lightweight
474 * strbuf_add_absolute_path() instead.
476 extern void strbuf_add_real_path(struct strbuf *sb, const char *path);
480 * Normalize in-place the path contained in the strbuf. See
481 * normalize_path_copy() for details. If an error occurs, the contents of "sb"
482 * are left untouched, and -1 is returned.
484 extern int strbuf_normalize_path(struct strbuf *sb);
487 * Strip whitespace from a buffer. The second parameter controls if
488 * comments are considered contents to be removed or not.
490 extern void strbuf_stripspace(struct strbuf *buf, int skip_comments);
492 static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix)
494 if (strip_suffix_mem(sb->buf, &sb->len, suffix)) {
495 strbuf_setlen(sb, sb->len);
496 return 1;
497 } else
498 return 0;
502 * Split str (of length slen) at the specified terminator character.
503 * Return a null-terminated array of pointers to strbuf objects
504 * holding the substrings. The substrings include the terminator,
505 * except for the last substring, which might be unterminated if the
506 * original string did not end with a terminator. If max is positive,
507 * then split the string into at most max substrings (with the last
508 * substring containing everything following the (max-1)th terminator
509 * character).
511 * The most generic form is `strbuf_split_buf`, which takes an arbitrary
512 * pointer/len buffer. The `_str` variant takes a NUL-terminated string,
513 * the `_max` variant takes a strbuf, and just `strbuf_split` is a convenience
514 * wrapper to drop the `max` parameter.
516 * For lighter-weight alternatives, see string_list_split() and
517 * string_list_split_in_place().
519 extern struct strbuf **strbuf_split_buf(const char *, size_t,
520 int terminator, int max);
522 static inline struct strbuf **strbuf_split_str(const char *str,
523 int terminator, int max)
525 return strbuf_split_buf(str, strlen(str), terminator, max);
528 static inline struct strbuf **strbuf_split_max(const struct strbuf *sb,
529 int terminator, int max)
531 return strbuf_split_buf(sb->buf, sb->len, terminator, max);
534 static inline struct strbuf **strbuf_split(const struct strbuf *sb,
535 int terminator)
537 return strbuf_split_max(sb, terminator, 0);
541 * Free a NULL-terminated list of strbufs (for example, the return
542 * values of the strbuf_split*() functions).
544 extern void strbuf_list_free(struct strbuf **);
547 * Add the abbreviation, as generated by find_unique_abbrev, of `sha1` to
548 * the strbuf `sb`.
550 extern void strbuf_add_unique_abbrev(struct strbuf *sb,
551 const struct object_id *oid,
552 int abbrev_len);
555 * Launch the user preferred editor to edit a file and fill the buffer
556 * with the file's contents upon the user completing their editing. The
557 * third argument can be used to set the environment which the editor is
558 * run in. If the buffer is NULL the editor is launched as usual but the
559 * file's contents are not read into the buffer upon completion.
561 extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
563 extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size);
566 * Append s to sb, with the characters '<', '>', '&' and '"' converted
567 * into XML entities.
569 extern void strbuf_addstr_xml_quoted(struct strbuf *sb, const char *s);
572 * "Complete" the contents of `sb` by ensuring that either it ends with the
573 * character `term`, or it is empty. This can be used, for example,
574 * to ensure that text ends with a newline, but without creating an empty
575 * blank line if there is no content in the first place.
577 static inline void strbuf_complete(struct strbuf *sb, char term)
579 if (sb->len && sb->buf[sb->len - 1] != term)
580 strbuf_addch(sb, term);
583 static inline void strbuf_complete_line(struct strbuf *sb)
585 strbuf_complete(sb, '\n');
589 * Copy "name" to "sb", expanding any special @-marks as handled by
590 * interpret_branch_name(). The result is a non-qualified branch name
591 * (so "foo" or "origin/master" instead of "refs/heads/foo" or
592 * "refs/remotes/origin/master").
594 * Note that the resulting name may not be a syntactically valid refname.
596 * If "allowed" is non-zero, restrict the set of allowed expansions. See
597 * interpret_branch_name() for details.
599 extern void strbuf_branchname(struct strbuf *sb, const char *name,
600 unsigned allowed);
603 * Like strbuf_branchname() above, but confirm that the result is
604 * syntactically valid to be used as a local branch name in refs/heads/.
606 * The return value is "0" if the result is valid, and "-1" otherwise.
608 extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
610 extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
611 int reserved);
613 __attribute__((format (printf,1,2)))
614 extern int printf_ln(const char *fmt, ...);
615 __attribute__((format (printf,2,3)))
616 extern int fprintf_ln(FILE *fp, const char *fmt, ...);
618 char *xstrdup_tolower(const char *);
619 char *xstrdup_toupper(const char *);
622 * Create a newly allocated string using printf format. You can do this easily
623 * with a strbuf, but this provides a shortcut to save a few lines.
625 __attribute__((format (printf, 1, 0)))
626 char *xstrvfmt(const char *fmt, va_list ap);
627 __attribute__((format (printf, 1, 2)))
628 char *xstrfmt(const char *fmt, ...);
630 #endif /* STRBUF_H */