git/strbuf.h
Stefan Beller c7e5fe79b9 strbuf.h: format according to coding guidelines
The previous patch suggested the strbuf header to be the leading example
of how we would want our APIs to be documented. This may lead to some
scrutiny of that code and the coding style (which is different from the
API documentation style) and hence might be taken as an example on how
to format code as well.

So let's format strbuf.h in a way that we'd like to see:
* omit the extern keyword from function declarations
* name all parameters (usually the parameters are obvious from its type,
  but consider exceptions like
  `int strbuf_getwholeline_fd(struct strbuf *, int, int);`
* break overly long lines

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-29 11:21:05 -07:00

661 lines
21 KiB
C

#ifndef STRBUF_H
#define STRBUF_H
struct string_list;
/**
* 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
* ---------------
*/
/**
* 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 { .alloc = 0, .len = 0, .buf = strbuf_slopbuf }
/*
* Predeclare this here, since cache.h includes this file before it defines the
* struct.
*/
struct object_id;
/**
* 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.
*/
void strbuf_init(struct strbuf *sb, size_t alloc);
/**
* Release a string buffer and the memory it used. After this call, the
* strbuf points to an empty string that does not need to be free()ed, as
* if it had been set to `STRBUF_INIT` and never modified.
*
* To clear a strbuf in preparation for further use without the overhead
* of free()ing and malloc()ing again, use strbuf_reset() instead.
*/
void strbuf_release(struct strbuf *sb);
/**
* 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.
*
* The strbuf that previously held the string is reset to `STRBUF_INIT` so
* it can be reused after calling this function.
*/
char *strbuf_detach(struct strbuf *sb, size_t *sz);
/**
* 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.
*/
void strbuf_attach(struct strbuf *sb, void *str, size_t len, size_t mem);
/**
* Swap the contents of two string buffers.
*/
static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
{
SWAP(*a, *b);
}
/**
* 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.
*/
void strbuf_grow(struct strbuf *sb, size_t amount);
/**
* 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))
die("BUG: strbuf_setlen() beyond buffer");
sb->len = len;
if (sb->buf != strbuf_slopbuf)
sb->buf[len] = '\0';
else
assert(!strbuf_slopbuf[0]);
}
/**
* Empty the buffer by setting the size of it to zero.
*/
#define strbuf_reset(sb) strbuf_setlen(sb, 0)
/**
* Functions related to the contents of the buffer
* -----------------------------------------------
*/
/**
* Strip whitespace from the beginning (`ltrim`), end (`rtrim`), or both side
* (`trim`) of a string.
*/
void strbuf_trim(struct strbuf *sb);
void strbuf_rtrim(struct strbuf *sb);
void strbuf_ltrim(struct strbuf *sb);
/* Strip trailing directory separators */
void strbuf_trim_trailing_dir_sep(struct strbuf *sb);
/**
* Replace the contents of the strbuf with a reencoded form. Returns -1
* on error, 0 on success.
*/
int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
/**
* Lowercase each character in the buffer using `tolower`.
*/
void strbuf_tolower(struct strbuf *sb);
/**
* 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.
*/
int strbuf_cmp(const struct strbuf *first, const struct strbuf *second);
/**
* 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.
*/
/**
* Add a single character to the buffer.
*/
static inline void strbuf_addch(struct strbuf *sb, int c)
{
if (!strbuf_avail(sb))
strbuf_grow(sb, 1);
sb->buf[sb->len++] = c;
sb->buf[sb->len] = '\0';
}
/**
* Add a character the specified number of times to the buffer.
*/
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.
*/
void strbuf_insert(struct strbuf *sb, size_t pos, const void *, size_t);
/**
* Remove given amount of data from a given position of the buffer.
*/
void strbuf_remove(struct strbuf *sb, size_t pos, size_t len);
/**
* Remove the bytes between `pos..pos+len` and replace it with the given
* data.
*/
void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
const void *data, size_t data_len);
/**
* Add a NUL-terminated string to the buffer. Each line will be prepended
* by a comment character and a blank.
*/
void strbuf_add_commented_lines(struct strbuf *out,
const char *buf, size_t size);
/**
* Add data of given length to the buffer.
*/
void strbuf_add(struct strbuf *sb, const void *data, size_t len);
/**
* 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.
*/
void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2);
/**
* 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);
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;
};
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.
*/
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).
*/
void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
/**
* Add a formatted string to the buffer.
*/
__attribute__((format (printf,2,3)))
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)))
void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...);
__attribute__((format (printf,2,0)))
void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
/**
* Add the time specified by `tm`, as formatted by `strftime`.
* `tz_offset` is in decimal hhmm format, e.g. -600 means six hours west
* of Greenwich, and it's used to expand %z internally. However, tokens
* with modifiers (e.g. %Ez) are passed to `strftime`.
* `suppress_tz_name`, when set, expands %Z internally to the empty
* string rather than passing it to `strftime`.
*/
void strbuf_addftime(struct strbuf *sb, const char *fmt,
const struct tm *tm, int tz_offset,
int suppress_tz_name);
/**
* 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_*()`
* family of functions have the same behaviour as well.
*/
size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *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.
*/
ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint);
/**
* Read the contents of a given file descriptor partially by using only one
* attempt of xread. The third argument can be used to give a hint about the
* file size, to avoid reallocs. Returns the number of new bytes appended to
* the sb.
*/
ssize_t strbuf_read_once(struct strbuf *sb, 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.
* Return the number of bytes read or a negative value if some error
* occurred while opening or reading the file.
*/
ssize_t 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.
*/
int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
/**
* Write the whole content of the strbuf to the stream not stopping at
* NUL bytes.
*/
ssize_t strbuf_write(struct strbuf *sb, FILE *stream);
/**
* Read a line from a FILE *, overwriting the existing contents of
* the strbuf. The strbuf_getline*() family of functions share
* this signature, but have different line termination conventions.
*
* 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`.
*/
typedef int (*strbuf_getline_fn)(struct strbuf *, FILE *);
/* Uses LF as the line terminator */
int strbuf_getline_lf(struct strbuf *sb, FILE *fp);
/* Uses NUL as the line terminator */
int strbuf_getline_nul(struct strbuf *sb, FILE *fp);
/*
* Similar to strbuf_getline_lf(), but additionally treats a CR that
* comes immediately before the LF as part of the terminator.
* This is the most friendly version to be used to read "text" files
* that can come from platforms whose native text format is CRLF
* terminated.
*/
int strbuf_getline(struct strbuf *sb, FILE *file);
/**
* Like `strbuf_getline`, but keeps the trailing terminator (if
* any) in the buffer.
*/
int strbuf_getwholeline(struct strbuf *sb, FILE *file, int term);
/**
* 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.
*/
int strbuf_getwholeline_fd(struct strbuf *sb, int fd, int term);
/**
* Set the buffer to the path of the current working directory.
*/
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.
*/
void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
/**
* Canonize `path` (make it absolute, resolve symlinks, remove extra
* slashes) and append it to `sb`. Die with an informative error
* message if there is a problem.
*
* The directory part of `path` (i.e., everything up to the last
* dir_sep) must denote a valid, existing directory, but the last
* component need not exist.
*
* Callers that don't mind links should use the more lightweight
* strbuf_add_absolute_path() instead.
*/
void strbuf_add_real_path(struct strbuf *sb, const char *path);
/**
* Normalize in-place the path contained in the strbuf. See
* normalize_path_copy() for details. If an error occurs, the contents of "sb"
* are left untouched, and -1 is returned.
*/
int strbuf_normalize_path(struct strbuf *sb);
/**
* Strip whitespace from a buffer. The second parameter controls if
* comments are considered contents to be removed or not.
*/
void strbuf_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().
*/
struct strbuf **strbuf_split_buf(const char *str, size_t len,
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);
}
/*
* Adds all strings of a string list to the strbuf, separated by the given
* separator. For example, if sep is
* ', '
* and slist contains
* ['element1', 'element2', ..., 'elementN'],
* then write:
* 'element1, element2, ..., elementN'
* to str. If only one element, just write "element1" to str.
*/
void strbuf_add_separated_string_list(struct strbuf *str,
const char *sep,
struct string_list *slist);
/**
* Free a NULL-terminated list of strbufs (for example, the return
* values of the strbuf_split*() functions).
*/
void strbuf_list_free(struct strbuf **list);
/**
* Add the abbreviation, as generated by find_unique_abbrev, of `sha1` to
* the strbuf `sb`.
*/
void strbuf_add_unique_abbrev(struct strbuf *sb,
const struct object_id *oid,
int abbrev_len);
/**
* 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.
*/
int launch_editor(const char *path,
struct strbuf *buffer,
const char *const *env);
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.
*/
void strbuf_addstr_xml_quoted(struct strbuf *sb,
const char *s);
/**
* "Complete" the contents of `sb` by ensuring that either it ends with the
* character `term`, or it is empty. This can be used, for example,
* to ensure that text ends with a newline, but without creating an empty
* blank line if there is no content in the first place.
*/
static inline void strbuf_complete(struct strbuf *sb, char term)
{
if (sb->len && sb->buf[sb->len - 1] != term)
strbuf_addch(sb, term);
}
static inline void strbuf_complete_line(struct strbuf *sb)
{
strbuf_complete(sb, '\n');
}
/*
* Copy "name" to "sb", expanding any special @-marks as handled by
* interpret_branch_name(). The result is a non-qualified branch name
* (so "foo" or "origin/master" instead of "refs/heads/foo" or
* "refs/remotes/origin/master").
*
* Note that the resulting name may not be a syntactically valid refname.
*
* If "allowed" is non-zero, restrict the set of allowed expansions. See
* interpret_branch_name() for details.
*/
void strbuf_branchname(struct strbuf *sb, const char *name,
unsigned allowed);
/*
* Like strbuf_branchname() above, but confirm that the result is
* syntactically valid to be used as a local branch name in refs/heads/.
*
* The return value is "0" if the result is valid, and "-1" otherwise.
*/
int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
void strbuf_addstr_urlencode(struct strbuf *sb, const char *name,
int reserved);
__attribute__((format (printf,1,2)))
int printf_ln(const char *fmt, ...);
__attribute__((format (printf,2,3)))
int fprintf_ln(FILE *fp, const char *fmt, ...);
char *xstrdup_tolower(const char *);
char *xstrdup_toupper(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.
*/
__attribute__((format (printf, 1, 0)))
char *xstrvfmt(const char *fmt, va_list ap);
__attribute__((format (printf, 1, 2)))
char *xstrfmt(const char *fmt, ...);
#endif /* STRBUF_H */