X-Git-Url: http://git.ipfire.org/?a=blobdiff_plain;f=strbuf.h;h=1883494ca3ad4931640c2a295c94800e287c1664;hb=d468fa2721d1ff918c0991e9e1f762872b3f82ae;hp=652b6c432b325aaed29d7d374994a2a95d11a7c8;hpb=fb06b5280ea05d75515fa780cf08d4ec9d6fe101;p=thirdparty%2Fgit.git

diff --git a/strbuf.h b/strbuf.h
index 652b6c432b..1883494ca3 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -1,22 +1,112 @@
 #ifndef STRBUF_H
 #define STRBUF_H
 
-/* See Documentation/technical/api-strbuf.txt */
+/**
+ * strbuf's are meant to be used with all the usual C string and memory
+ * APIs. Given that the length of the buffer is known, it's often better to
+ * use the mem* functions than a str* one (memchr vs. strchr e.g.).
+ * Though, one has to be careful about the fact that str* functions often
+ * stop on NULs and that strbufs may have embedded NULs.
+ *
+ * A strbuf is NUL terminated for convenience, but no function in the
+ * strbuf API actually relies on the string being free of NULs.
+ *
+ * strbufs have some invariants that are very important to keep in mind:
+ *
+ *  - The `buf` member is never NULL, so it can be used in any usual C
+ *    string operations safely. strbuf's _have_ to be initialized either by
+ *    `strbuf_init()` or by `= STRBUF_INIT` before the invariants, though.
+ *
+ *    Do *not* assume anything on what `buf` really is (e.g. if it is
+ *    allocated memory or not), use `strbuf_detach()` to unwrap a memory
+ *    buffer from its strbuf shell in a safe way. That is the sole supported
+ *    way. This will give you a malloced buffer that you can later `free()`.
+ *
+ *    However, it is totally safe to modify anything in the string pointed by
+ *    the `buf` member, between the indices `0` and `len-1` (inclusive).
+ *
+ *  - The `buf` member is a byte array that has at least `len + 1` bytes
+ *    allocated. The extra byte is used to store a `'\0'`, allowing the
+ *    `buf` member to be a valid C-string. Every strbuf function ensure this
+ *    invariant is preserved.
+ *
+ *    NOTE: It is OK to "play" with the buffer directly if you work it this
+ *    way:
+ *
+ *        strbuf_grow(sb, SOME_SIZE); <1>
+ *        strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
+ *
+ *    <1> Here, the memory array starting at `sb->buf`, and of length
+ *    `strbuf_avail(sb)` is all yours, and you can be sure that
+ *    `strbuf_avail(sb)` is at least `SOME_SIZE`.
+ *
+ *    NOTE: `SOME_OTHER_SIZE` must be smaller or equal to `strbuf_avail(sb)`.
+ *
+ *    Doing so is safe, though if it has to be done in many places, adding the
+ *    missing API to the strbuf module is the way to go.
+ *
+ *    WARNING: Do _not_ assume that the area that is yours is of size `alloc
+ *    - 1` even if it's true in the current implementation. Alloc is somehow a
+ *    "private" member that should not be messed with. Use `strbuf_avail()`
+ *    instead.
+*/
+
+/**
+ * Data Structures
+ * ---------------
+ */
 
-extern char strbuf_slopbuf[];
+/**
+ * This is the string buffer structure. The `len` member can be used to
+ * determine the current length of the string, and `buf` member provides
+ * access to the string itself.
+ */
 struct strbuf {
 	size_t alloc;
 	size_t len;
 	char *buf;
 };
 
+extern char strbuf_slopbuf[];
 #define STRBUF_INIT  { 0, 0, strbuf_slopbuf }
 
-/*----- strbuf life cycle -----*/
+/**
+ * Life Cycle Functions
+ * --------------------
+ */
+
+/**
+ * Initialize the structure. The second parameter can be zero or a bigger
+ * number to allocate memory, in case you want to prevent further reallocs.
+ */
 extern void strbuf_init(struct strbuf *, size_t);
+
+/**
+ * Release a string buffer and the memory it used. You should not use the
+ * string buffer after using this function, unless you initialize it again.
+ */
 extern void strbuf_release(struct strbuf *);
+
+/**
+ * Detach the string from the strbuf and returns it; you now own the
+ * storage the string occupies and it is your responsibility from then on
+ * to release it with `free(3)` when you are done with it.
+ */
 extern char *strbuf_detach(struct strbuf *, size_t *);
+
+/**
+ * Attach a string to a buffer. You should specify the string to attach,
+ * the current length of the string and the amount of allocated memory.
+ * The amount must be larger than the string length, because the string you
+ * pass is supposed to be a NUL-terminated string.  This string _must_ be
+ * malloc()ed, and after attaching, the pointer cannot be relied upon
+ * anymore, and neither be free()d directly.
+ */
 extern void strbuf_attach(struct strbuf *, void *, size_t, size_t);
+
+/**
+ * Swap the contents of two string buffers.
+ */
 static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
 {
 	struct strbuf tmp = *a;
@@ -24,14 +114,36 @@ static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
 	*b = tmp;
 }
 
-/*----- strbuf size related -----*/
+
+/**
+ * Functions related to the size of the buffer
+ * -------------------------------------------
+ */
+
+/**
+ * Determine the amount of allocated but unused memory.
+ */
 static inline size_t strbuf_avail(const struct strbuf *sb)
 {
 	return sb->alloc ? sb->alloc - sb->len - 1 : 0;
 }
 
+/**
+ * Ensure that at least this amount of unused memory is available after
+ * `len`. This is used when you know a typical size for what you will add
+ * and want to avoid repetitive automatic resizing of the underlying buffer.
+ * This is never a needed operation, but can be critical for performance in
+ * some cases.
+ */
 extern void strbuf_grow(struct strbuf *, size_t);
 
+/**
+ * Set the length of the buffer to a given value. This function does *not*
+ * allocate new memory, so you should not perform a `strbuf_setlen()` to a
+ * length that is larger than `len + strbuf_avail()`. `strbuf_setlen()` is
+ * just meant as a 'please fix invariants from this strbuf I just messed
+ * with'.
+ */
 static inline void strbuf_setlen(struct strbuf *sb, size_t len)
 {
 	if (len > (sb->alloc ? sb->alloc - 1 : 0))
@@ -39,78 +151,58 @@ static inline void strbuf_setlen(struct strbuf *sb, size_t len)
 	sb->len = len;
 	sb->buf[len] = '\0';
 }
+
+/**
+ * Empty the buffer by setting the size of it to zero.
+ */
 #define strbuf_reset(sb)  strbuf_setlen(sb, 0)
 
-/*----- content related -----*/
+
+/**
+ * Functions related to the contents of the buffer
+ * -----------------------------------------------
+ */
+
+/**
+ * Strip whitespace from the beginning (`ltrim`), end (`rtrim`), or both side
+ * (`trim`) of a string.
+ */
 extern void strbuf_trim(struct strbuf *);
 extern void strbuf_rtrim(struct strbuf *);
 extern void strbuf_ltrim(struct strbuf *);
-extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
-extern void strbuf_tolower(struct strbuf *sb);
-extern int strbuf_cmp(const struct strbuf *, const struct strbuf *);
 
-static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix)
-{
-	if (strip_suffix_mem(sb->buf, &sb->len, suffix)) {
-		strbuf_setlen(sb, sb->len);
-		return 1;
-	} else
-		return 0;
-}
-
-/*
- * Split str (of length slen) at the specified terminator character.
- * Return a null-terminated array of pointers to strbuf objects
- * holding the substrings.  The substrings include the terminator,
- * except for the last substring, which might be unterminated if the
- * original string did not end with a terminator.  If max is positive,
- * then split the string into at most max substrings (with the last
- * substring containing everything following the (max-1)th terminator
- * character).
- *
- * For lighter-weight alternatives, see string_list_split() and
- * string_list_split_in_place().
+/**
+ * Replace the contents of the strbuf with a reencoded form.  Returns -1
+ * on error, 0 on success.
  */
-extern struct strbuf **strbuf_split_buf(const char *, size_t,
-					int terminator, int max);
+extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
 
-/*
- * Split a NUL-terminated string at the specified terminator
- * character.  See strbuf_split_buf() for more information.
+/**
+ * Lowercase each character in the buffer using `tolower`.
  */
-static inline struct strbuf **strbuf_split_str(const char *str,
-					       int terminator, int max)
-{
-	return strbuf_split_buf(str, strlen(str), terminator, max);
-}
+extern void strbuf_tolower(struct strbuf *sb);
 
-/*
- * Split a strbuf at the specified terminator character.  See
- * strbuf_split_buf() for more information.
+/**
+ * Compare two buffers. Returns an integer less than, equal to, or greater
+ * than zero if the first buffer is found, respectively, to be less than,
+ * to match, or be greater than the second buffer.
  */
-static inline struct strbuf **strbuf_split_max(const struct strbuf *sb,
-						int terminator, int max)
-{
-	return strbuf_split_buf(sb->buf, sb->len, terminator, max);
-}
+extern int strbuf_cmp(const struct strbuf *, const struct strbuf *);
 
-/*
- * Split a strbuf at the specified terminator character.  See
- * strbuf_split_buf() for more information.
- */
-static inline struct strbuf **strbuf_split(const struct strbuf *sb,
-					   int terminator)
-{
-	return strbuf_split_max(sb, terminator, 0);
-}
 
-/*
- * Free a NULL-terminated list of strbufs (for example, the return
- * values of the strbuf_split*() functions).
+/**
+ * Adding data to the buffer
+ * -------------------------
+ *
+ * NOTE: All of the functions in this section will grow the buffer as
+ * necessary.  If they fail for some reason other than memory shortage and the
+ * buffer hadn't been allocated before (i.e. the `struct strbuf` was set to
+ * `STRBUF_INIT`), then they will free() it.
  */
-extern void strbuf_list_free(struct strbuf **);
 
-/*----- add data in your buffer -----*/
+/**
+ * Add a single character to the buffer.
+ */
 static inline void strbuf_addch(struct strbuf *sb, int c)
 {
 	strbuf_grow(sb, 1);
@@ -118,47 +210,276 @@ static inline void strbuf_addch(struct strbuf *sb, int c)
 	sb->buf[sb->len] = '\0';
 }
 
+/**
+ * Add a character the specified number of times to the buffer.
+ */
+extern void strbuf_addchars(struct strbuf *sb, int c, size_t n);
+
+/**
+ * Insert data to the given position of the buffer. The remaining contents
+ * will be shifted, not overwritten.
+ */
 extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
+
+/**
+ * Remove given amount of data from a given position of the buffer.
+ */
 extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
 
-/* splice pos..pos+len with given data */
+/**
+ * Remove the bytes between `pos..pos+len` and replace it with the given
+ * data.
+ */
 extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
-                          const void *, size_t);
+			  const void *, size_t);
 
+/**
+ * Add a NUL-terminated string to the buffer. Each line will be prepended
+ * by a comment character and a blank.
+ */
 extern void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size);
 
+
+/**
+ * Add data of given length to the buffer.
+ */
 extern void strbuf_add(struct strbuf *, const void *, size_t);
+
+/**
+ * Add a NUL-terminated string to the buffer.
+ *
+ * NOTE: This function will *always* be implemented as an inline or a macro
+ * using strlen, meaning that this is efficient to write things like:
+ *
+ *     strbuf_addstr(sb, "immediate string");
+ *
+ */
 static inline void strbuf_addstr(struct strbuf *sb, const char *s)
 {
 	strbuf_add(sb, s, strlen(s));
 }
+
+/**
+ * Copy the contents of another buffer at the end of the current one.
+ */
 static inline void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
 {
 	strbuf_grow(sb, sb2->len);
 	strbuf_add(sb, sb2->buf, sb2->len);
 }
+
+/**
+ * Copy part of the buffer from a given position till a given length to the
+ * end of the buffer.
+ */
 extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
-extern void strbuf_addchars(struct strbuf *sb, int c, size_t n);
 
+/**
+ * This function can be used to expand a format string containing
+ * placeholders. To that end, it parses the string and calls the specified
+ * function for every percent sign found.
+ *
+ * The callback function is given a pointer to the character after the `%`
+ * and a pointer to the struct strbuf.  It is expected to add the expanded
+ * version of the placeholder to the strbuf, e.g. to add a newline
+ * character if the letter `n` appears after a `%`.  The function returns
+ * the length of the placeholder recognized and `strbuf_expand()` skips
+ * over it.
+ *
+ * The format `%%` is automatically expanded to a single `%` as a quoting
+ * mechanism; callers do not need to handle the `%` placeholder themselves,
+ * and the callback function will not be invoked for this placeholder.
+ *
+ * All other characters (non-percent and not skipped ones) are copied
+ * verbatim to the strbuf.  If the callback returned zero, meaning that the
+ * placeholder is unknown, then the percent sign is copied, too.
+ *
+ * In order to facilitate caching and to make it possible to give
+ * parameters to the callback, `strbuf_expand()` passes a context pointer,
+ * which can be used by the programmer of the callback as she sees fit.
+ */
 typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);
 extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);
+
+/**
+ * Used as callback for `strbuf_expand()`, expects an array of
+ * struct strbuf_expand_dict_entry as context, i.e. pairs of
+ * placeholder and replacement string.  The array needs to be
+ * terminated by an entry with placeholder set to NULL.
+ */
 struct strbuf_expand_dict_entry {
 	const char *placeholder;
 	const char *value;
 };
 extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);
+
+/**
+ * Append the contents of one strbuf to another, quoting any
+ * percent signs ("%") into double-percents ("%%") in the
+ * destination. This is useful for literal data to be fed to either
+ * strbuf_expand or to the *printf family of functions.
+ */
 extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
 
+/**
+ * Append the given byte size as a human-readable string (i.e. 12.23 KiB,
+ * 3.50 MiB).
+ */
+extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
+
+/**
+ * Add a formatted string to the buffer.
+ */
 __attribute__((format (printf,2,3)))
 extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
+
+/**
+ * Add a formatted string prepended by a comment character and a
+ * blank to the buffer.
+ */
 __attribute__((format (printf, 2, 3)))
 extern void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...);
+
 __attribute__((format (printf,2,0)))
 extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
 
+/**
+ * Read a given size of data from a FILE* pointer to the buffer.
+ *
+ * NOTE: The buffer is rewound if the read fails. If -1 is returned,
+ * `errno` must be consulted, like you would do for `read(3)`.
+ * `strbuf_read()`, `strbuf_read_file()` and `strbuf_getline()` has the
+ * same behaviour as well.
+ */
+extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
+
+/**
+ * Read the contents of a given file descriptor. The third argument can be
+ * used to give a hint about the file size, to avoid reallocs.  If read fails,
+ * any partial read is undone.
+ */
+extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
+
+/**
+ * Read the contents of a file, specified by its path. The third argument
+ * can be used to give a hint about the file size, to avoid reallocs.
+ */
+extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
+
+/**
+ * Read the target of a symbolic link, specified by its path.  The third
+ * argument can be used to give a hint about the size, to avoid reallocs.
+ */
+extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
+
+/**
+ * Read a line from a FILE *, overwriting the existing contents
+ * of the strbuf. The second argument specifies the line
+ * terminator character, typically `'\n'`.
+ * Reading stops after the terminator or at EOF.  The terminator
+ * is removed from the buffer before returning.  Returns 0 unless
+ * there was nothing left before EOF, in which case it returns `EOF`.
+ */
+extern int strbuf_getline(struct strbuf *, FILE *, int);
+
+/**
+ * Like `strbuf_getline`, but keeps the trailing terminator (if
+ * any) in the buffer.
+ */
+extern int strbuf_getwholeline(struct strbuf *, FILE *, int);
+
+/**
+ * Like `strbuf_getwholeline`, but operates on a file descriptor.
+ * It reads one character at a time, so it is very slow.  Do not
+ * use it unless you need the correct position in the file
+ * descriptor.
+ */
+extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
+
+/**
+ * Set the buffer to the path of the current working directory.
+ */
+extern int strbuf_getcwd(struct strbuf *sb);
+
+/**
+ * Add a path to a buffer, converting a relative path to an
+ * absolute one in the process.  Symbolic links are not
+ * resolved.
+ */
+extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
+
+/**
+ * Strip whitespace from a buffer. The second parameter controls if
+ * comments are considered contents to be removed or not.
+ */
+extern void stripspace(struct strbuf *buf, int skip_comments);
+
+static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix)
+{
+	if (strip_suffix_mem(sb->buf, &sb->len, suffix)) {
+		strbuf_setlen(sb, sb->len);
+		return 1;
+	} else
+		return 0;
+}
+
+/**
+ * Split str (of length slen) at the specified terminator character.
+ * Return a null-terminated array of pointers to strbuf objects
+ * holding the substrings.  The substrings include the terminator,
+ * except for the last substring, which might be unterminated if the
+ * original string did not end with a terminator.  If max is positive,
+ * then split the string into at most max substrings (with the last
+ * substring containing everything following the (max-1)th terminator
+ * character).
+ *
+ * The most generic form is `strbuf_split_buf`, which takes an arbitrary
+ * pointer/len buffer. The `_str` variant takes a NUL-terminated string,
+ * the `_max` variant takes a strbuf, and just `strbuf_split` is a convenience
+ * wrapper to drop the `max` parameter.
+ *
+ * For lighter-weight alternatives, see string_list_split() and
+ * string_list_split_in_place().
+ */
+extern struct strbuf **strbuf_split_buf(const char *, size_t,
+					int terminator, int max);
+
+static inline struct strbuf **strbuf_split_str(const char *str,
+					       int terminator, int max)
+{
+	return strbuf_split_buf(str, strlen(str), terminator, max);
+}
+
+static inline struct strbuf **strbuf_split_max(const struct strbuf *sb,
+						int terminator, int max)
+{
+	return strbuf_split_buf(sb->buf, sb->len, terminator, max);
+}
+
+static inline struct strbuf **strbuf_split(const struct strbuf *sb,
+					   int terminator)
+{
+	return strbuf_split_max(sb, terminator, 0);
+}
+
+/**
+ * Free a NULL-terminated list of strbufs (for example, the return
+ * values of the strbuf_split*() functions).
+ */
+extern void strbuf_list_free(struct strbuf **);
+
+/**
+ * Launch the user preferred editor to edit a file and fill the buffer
+ * with the file's contents upon the user completing their editing. The
+ * third argument can be used to set the environment which the editor is
+ * run in. If the buffer is NULL the editor is launched as usual but the
+ * file's contents are not read into the buffer upon completion.
+ */
+extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
+
 extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size);
 
-/*
+/**
  * Append s to sb, with the characters '<', '>', '&' and '"' converted
  * into XML entities.
  */
@@ -170,28 +491,11 @@ static inline void strbuf_complete_line(struct strbuf *sb)
 		strbuf_addch(sb, '\n');
 }
 
-extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
-/* XXX: if read fails, any partial read is undone */
-extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
-extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
-extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
-extern int strbuf_getcwd(struct strbuf *sb);
-
-extern int strbuf_getwholeline(struct strbuf *, FILE *, int);
-extern int strbuf_getline(struct strbuf *, FILE *, int);
-extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
-
-extern void stripspace(struct strbuf *buf, int skip_comments);
-extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
-
 extern int strbuf_branchname(struct strbuf *sb, const char *name);
 extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
 
 extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
 				    int reserved);
-extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
-
-extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
 
 __attribute__((format (printf,1,2)))
 extern int printf_ln(const char *fmt, ...);
@@ -200,7 +504,7 @@ extern int fprintf_ln(FILE *fp, const char *fmt, ...);
 
 char *xstrdup_tolower(const char *);
 
-/*
+/**
  * Create a newly allocated string using printf format. You can do this easily
  * with a strbuf, but this provides a shortcut to save a few lines.
  */