[FFmpeg-devel] [PATCH] lavu: add escape API
Clément Bœsch
ubitux at gmail.com
Sun Dec 16 21:07:59 CET 2012
On Sun, Dec 16, 2012 at 12:35:52PM +0100, Stefano Sabatini wrote:
> The escape API will be useful to perform escaping programmatically, which
> is required when crafting argument strings, and will be used for context
> printing as well.
>
> TODO: bump minor, add APIchanges entry
> ---
> libavutil/avstring.c | 18 ++++++++++++
> libavutil/avstring.h | 19 +++++++++++++
> libavutil/bprint.c | 49 +++++++++++++++++++++++++++++++++
> libavutil/bprint.h | 14 ++++++++++
> tools/ffescape.c | 75 ++++----------------------------------------------
> 5 files changed, 105 insertions(+), 70 deletions(-)
>
> diff --git a/libavutil/avstring.c b/libavutil/avstring.c
> index f03df67..b2af333 100644
> --- a/libavutil/avstring.c
> +++ b/libavutil/avstring.c
> @@ -26,6 +26,7 @@
> #include <ctype.h>
> #include "avstring.h"
> #include "mem.h"
> +#include "bprint.h"
>
> int av_strstart(const char *str, const char *pfx, const char **ptr)
> {
> @@ -211,6 +212,23 @@ int av_strncasecmp(const char *a, const char *b, size_t n)
> return c1 - c2;
> }
>
> +int av_escape(char **dst, const char *src, const char *special_chars,
> + enum AVEscapeMode mode)
> +{
> + AVBPrint dstbuf;
> +
> + av_bprint_init(&dstbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
> +
> + av_bprint_escape(&dstbuf, src, special_chars, mode);
> + if (!av_bprint_is_complete(&dstbuf)) {
> + av_bprint_finalize(&dstbuf, NULL);
> + return AVERROR(ENOMEM);
> + } else {
> + av_bprint_finalize(&dstbuf, dst);
> + return 0;
> + }
> +}
> +
> #ifdef TEST
>
> #include "common.h"
> diff --git a/libavutil/avstring.h b/libavutil/avstring.h
> index f73d6e7..0940e2b 100644
> --- a/libavutil/avstring.h
> +++ b/libavutil/avstring.h
> @@ -202,6 +202,25 @@ int av_strcasecmp(const char *a, const char *b);
> */
> int av_strncasecmp(const char *a, const char *b, size_t n);
>
> +enum AVEscapeMode {
> + AV_ESCAPE_MODE_FULL, ///< escape each single special character and whitespace by prefixing '\'
> + AV_ESCAPE_MODE_LAZY, ///< as AV_ESCAPE_MODE_FULL, but only escape whitespaces at the begin and at the end of the string
Does this mean: "whitespaces are only escaped when found at begin & end"
or "do not escape anything except whitespaces at begin & end"?
> + AV_ESCAPE_MODE_QUOTE, ///< perform quote-escaping
> +};
> +
> +#define AV_WHITESPACES " \n\t"
> +
This could be made private I believe.
> +/**
> + * Escape string in src, and put the escaped string in an allocated
> + * string in *dst, which must be freed with av_free().
> + *
> + * @param special_chars string containing the special characters which need to be escaped
> + * @param mode escape mode to employ
> + * @return >=0 in case of success, or a negative error code in case of error
> + */
> +int av_escape(char **dst, const char *src, const char *special_chars,
> + enum AVEscapeMode mode);
> +
> /**
> * @}
> */
> diff --git a/libavutil/bprint.c b/libavutil/bprint.c
> index 4684ab4..6ea1e3e 100644
> --- a/libavutil/bprint.c
> +++ b/libavutil/bprint.c
> @@ -23,6 +23,7 @@
> #include <string.h>
> #include <time.h>
> #include "avassert.h"
> +#include "avstring.h"
> #include "bprint.h"
> #include "common.h"
> #include "error.h"
> @@ -217,6 +218,54 @@ int av_bprint_finalize(AVBPrint *buf, char **ret_str)
> return ret;
> }
>
> +int av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
> + enum AVEscapeMode mode)
> +{
> + switch (mode) {
> + case AV_ESCAPE_MODE_FULL:
> + case AV_ESCAPE_MODE_LAZY:
> + /* \-escape characters */
> +
> + if (mode == AV_ESCAPE_MODE_LAZY && strchr(AV_WHITESPACES, *src))
> + av_bprintf(dstbuf, "\\%c", *src++);
> +
> + for (; *src; src++) {
> + if ((special_chars && strchr(special_chars, *src)) ||
> + strchr("'\\", *src) ||
> + (mode == AV_ESCAPE_MODE_FULL && strchr(AV_WHITESPACES, *src)))
> + av_bprintf(dstbuf, "\\%c", *src);
> + else
> + av_bprint_chars(dstbuf, *src, 1);
> + }
> +
> + if (mode == AV_ESCAPE_MODE_LAZY &&
> + strchr(AV_WHITESPACES, dstbuf->str[dstbuf->len-1])) {
> + char c = dstbuf->str[dstbuf->len-1];
> + dstbuf->str[dstbuf->len-1] = '\\';
> + av_bprint_chars(dstbuf, c, 1);
> + }
> + break;
> +
> + case AV_ESCAPE_MODE_QUOTE:
> + /* enclose between '' the string */
> + av_bprint_chars(dstbuf, '\'', 1);
> + for (; *src; src++) {
> + if (*src == '\'')
> + av_bprintf(dstbuf, "'\\''");
> + else
> + av_bprint_chars(dstbuf, *src, 1);
> + }
> + av_bprint_chars(dstbuf, '\'', 1);
> + break;
> +
> + default:
> + /* unknown escape mode */
> + return AVERROR(EINVAL);
> + }
> +
> + return 0;
> +}
> +
> #ifdef TEST
>
> #undef printf
> diff --git a/libavutil/bprint.h b/libavutil/bprint.h
> index f3915fe..3506d7c 100644
> --- a/libavutil/bprint.h
> +++ b/libavutil/bprint.h
> @@ -22,6 +22,7 @@
> #define AVUTIL_BPRINT_H
>
> #include "attributes.h"
> +#include "avstring.h"
>
> /**
> * Define a structure with extra padding to a fixed size
> @@ -180,4 +181,17 @@ static inline int av_bprint_is_complete(AVBPrint *buf)
> */
> int av_bprint_finalize(AVBPrint *buf, char **ret_str);
>
> +/**
> + * Escape the content in src and append it to dstbuf.
> + *
> + * @param dstbuf already inited destination bprint buffer
> + * @param src string containing the text to escape
> + * @param special_chars list of special characters to escape
> + * @param mode escape mode to employ
> + * @return >= 0 in case of success, a negative value in case of error
> + * @see av_escape()
> + */
> +int av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
> + enum AVEscapeMode mode);
> +
> #endif /* AVUTIL_BPRINT_H */
> diff --git a/tools/ffescape.c b/tools/ffescape.c
> index d777fe4..6291547 100644
> --- a/tools/ffescape.c
> +++ b/tools/ffescape.c
> @@ -51,71 +51,6 @@ static void usage(void)
> "-s SPECIAL_CHARS set the list of special characters\n");
> }
>
> -#define WHITESPACES " \n\t"
> -
> -enum EscapeMode {
> - ESCAPE_MODE_FULL,
> - ESCAPE_MODE_LAZY,
> - ESCAPE_MODE_QUOTE,
> -};
> -
> -static int escape(char **dst, const char *src, const char *special_chars,
> - enum EscapeMode mode)
> -{
> - AVBPrint dstbuf;
> -
> - av_bprint_init(&dstbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
> -
> - switch (mode) {
> - case ESCAPE_MODE_FULL:
> - case ESCAPE_MODE_LAZY:
> - /* \-escape characters */
> -
> - if (mode == ESCAPE_MODE_LAZY && strchr(WHITESPACES, *src))
> - av_bprintf(&dstbuf, "\\%c", *src++);
> -
> - for (; *src; src++) {
> - if ((special_chars && strchr(special_chars, *src)) ||
> - strchr("'\\", *src) ||
> - (mode == ESCAPE_MODE_FULL && strchr(WHITESPACES, *src)))
> - av_bprintf(&dstbuf, "\\%c", *src);
> - else
> - av_bprint_chars(&dstbuf, *src, 1);
> - }
> -
> - if (mode == ESCAPE_MODE_LAZY && strchr(WHITESPACES, dstbuf.str[dstbuf.len-1])) {
> - char c = dstbuf.str[dstbuf.len-1];
> - dstbuf.str[dstbuf.len-1] = '\\';
> - av_bprint_chars(&dstbuf, c, 1);
> - }
> - break;
> -
> - case ESCAPE_MODE_QUOTE:
> - /* enclose between '' the string */
> - av_bprint_chars(&dstbuf, '\'', 1);
> - for (; *src; src++) {
> - if (*src == '\'')
> - av_bprintf(&dstbuf, "'\\''");
> - else
> - av_bprint_chars(&dstbuf, *src, 1);
> - }
> - av_bprint_chars(&dstbuf, '\'', 1);
> - break;
> -
> - default:
> - /* unknown escape mode */
> - return AVERROR(EINVAL);
> - }
> -
> - if (!av_bprint_is_complete(&dstbuf)) {
> - av_bprint_finalize(&dstbuf, NULL);
> - return AVERROR(ENOMEM);
> - } else {
> - av_bprint_finalize(&dstbuf, dst);
> - return 0;
> - }
> -}
> -
> int main(int argc, char **argv)
> {
> AVBPrint src;
> @@ -123,7 +58,7 @@ int main(int argc, char **argv)
> const char *outfilename = NULL, *infilename = NULL;
> FILE *outfile = NULL, *infile = NULL;
> const char *prompt = "=> ";
> - enum EscapeMode escape_mode = ESCAPE_MODE_LAZY;
> + enum AVEscapeMode escape_mode = AV_ESCAPE_MODE_LAZY;
> int level = 1;
> int echo = 0;
> char *special_chars = NULL;
> @@ -154,9 +89,9 @@ int main(int argc, char **argv)
> break;
> }
> case 'm':
> - if (!strcmp(optarg, "full")) escape_mode = ESCAPE_MODE_FULL;
> - else if (!strcmp(optarg, "lazy")) escape_mode = ESCAPE_MODE_LAZY;
> - else if (!strcmp(optarg, "quote")) escape_mode = ESCAPE_MODE_QUOTE;
> + if (!strcmp(optarg, "full")) escape_mode = AV_ESCAPE_MODE_FULL;
> + else if (!strcmp(optarg, "lazy")) escape_mode = AV_ESCAPE_MODE_LAZY;
> + else if (!strcmp(optarg, "quote")) escape_mode = AV_ESCAPE_MODE_QUOTE;
> else {
> av_log(NULL, AV_LOG_ERROR,
> "Invalid value '%s' for option -m, "
> @@ -219,7 +154,7 @@ int main(int argc, char **argv)
> /* escape */
> dst_buf = src_buf;
> while (level--) {
> - if (escape(&dst_buf, src_buf, special_chars, escape_mode) < 0) {
> + if (av_escape(&dst_buf, src_buf, special_chars, escape_mode) < 0) {
> av_log(NULL, AV_LOG_ERROR, "Could not escape string\n");
> return 1;
> }
LGTM otherwise.
--
Clément B.
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