From: Werner Koch Date: Thu, 11 Oct 2012 15:02:50 +0000 (+0200) Subject: gpgme-tool: Use membuf functions to build up strings. X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=HEAD;p=gpgme.git gpgme-tool: Use membuf functions to build up strings. * src/gpgme-tool.c (clear_membuf, init_membuf, put_membuf) (put_membuf_str, get_membuf, peek_membuf): Add membuf functions. Take from GnuPG master's common/membuf.[ch] and patch for our use. (result_xml_escape): Rewrite using new functions. -- First counting, then allocating, and finally copying data is prone to errors. We better use the membuf functions which make it much easier. --- diff --git a/src/gpgme-tool.c b/src/gpgme-tool.c index 057e428..eb1fbb8 100644 --- a/src/gpgme-tool.c +++ b/src/gpgme-tool.c @@ -474,6 +474,148 @@ argp_parse (const struct argp *argp, int argc, } #endif + +/* MEMBUF */ + +/* A simple implementation of a dynamic buffer. Use init_membuf() to + create a buffer, put_membuf to append bytes and get_membuf to + release and return the buffer. Allocation errors are detected but + only returned at the final get_membuf(), this helps not to clutter + the code with out-of-core checks. */ + +/* The definition of the structure is private, we only need it here, + so it can be allocated on the stack. */ +struct private_membuf_s +{ + size_t len; + size_t size; + char *buf; + int out_of_core; +}; + +typedef struct private_membuf_s membuf_t; + +/* Return the current length of the membuf. */ +#define get_membuf_len(a) ((a)->len) +#define is_membuf_ready(a) ((a)->buf || (a)->out_of_core) +#define MEMBUF_ZERO { 0, 0, NULL, 0} + + +static void +init_membuf (membuf_t *mb, int initiallen) +{ + mb->len = 0; + mb->size = initiallen; + mb->out_of_core = 0; + mb->buf = malloc (initiallen); + if (!mb->buf) + mb->out_of_core = errno; +} + + +/* Shift the the content of the membuf MB by AMOUNT bytes. The next + operation will then behave as if AMOUNT bytes had not been put into + the buffer. If AMOUNT is greater than the actual accumulated + bytes, the membuf is basically reset to its initial state. */ +#if 0 /* Not yet used. */ +static void +clear_membuf (membuf_t *mb, size_t amount) +{ + /* No need to clear if we are already out of core. */ + if (mb->out_of_core) + return; + if (amount >= mb->len) + mb->len = 0; + else + { + mb->len -= amount; + memmove (mb->buf, mb->buf+amount, mb->len); + } +} +#endif /* unused */ + +static void +put_membuf (membuf_t *mb, const void *buf, size_t len) +{ + if (mb->out_of_core || !len) + return; + + if (mb->len + len >= mb->size) + { + char *p; + + mb->size += len + 1024; + p = realloc (mb->buf, mb->size); + if (!p) + { + mb->out_of_core = errno ? errno : ENOMEM; + return; + } + mb->buf = p; + } + memcpy (mb->buf + mb->len, buf, len); + mb->len += len; +} + + +#if 0 /* Not yet used. */ +static void +put_membuf_str (membuf_t *mb, const char *string) +{ + put_membuf (mb, string, strlen (string)); +} +#endif /* unused */ + + +static void * +get_membuf (membuf_t *mb, size_t *len) +{ + char *p; + + if (mb->out_of_core) + { + if (mb->buf) + { + free (mb->buf); + mb->buf = NULL; + } + gpg_err_set_errno (mb->out_of_core); + return NULL; + } + + p = mb->buf; + if (len) + *len = mb->len; + mb->buf = NULL; + mb->out_of_core = ENOMEM; /* hack to make sure it won't get reused. */ + return p; +} + + +/* Peek at the membuf MB. On success a pointer to the buffer is + returned which is valid until the next operation on MB. If LEN is + not NULL the current LEN of the buffer is stored there. On error + NULL is returned and ERRNO is set. */ +#if 0 /* Not yet used. */ +static const void * +peek_membuf (membuf_t *mb, size_t *len) +{ + const char *p; + + if (mb->out_of_core) + { + gpg_err_set_errno (mb->out_of_core); + return NULL; + } + + p = mb->buf; + if (len) + *len = mb->len; + return p; +} +#endif /* unused */ + + /* SUPPORT. */ FILE *log_stream; @@ -658,7 +800,8 @@ result_xml_tag_start (struct result_xml_state *state, char *name, ...) return 0; } -const char * +/* Return a constant string with an XML entity for C. */ +static const char * result_xml_escape_replacement(char c) { switch (c) @@ -674,48 +817,32 @@ result_xml_escape_replacement(char c) } } -gpg_error_t +/* Escape DATA by replacing certain characters with their XML + entities. The result is stored in a newly allocated buffer which + address will be stored at BUF. Returns 0 on success. */ +static gpg_error_t result_xml_escape (const char *data, char **buf) { - int data_len, i, j = 1; + int data_len, i; const char *r; - char *b; + membuf_t mb; + init_membuf (&mb, 128); data_len = strlen (data); for (i = 0; i < data_len; i++) { - r = result_xml_escape_replacement(data[i]); + r = result_xml_escape_replacement (data[i]); if (r) - j += strlen (r); + put_membuf (&mb, r, strlen (r)); else - j += 1; + put_membuf (&mb, data+i, 1); } - - b = (char *) malloc (j); - if (! b) - return gpg_error_from_syserror (); - - j = 0; - for (i = 0; i < data_len; i++) - { - r = result_xml_escape_replacement(data[i]); - if (r) - { - strcpy (b + j, r); - j += strlen (r); - } - else - { - b[j] = data[i]; - j += 1; - } - } - b[j] = 0; - *buf = b; - - return 0; + put_membuf (&mb, "", 1); + *buf = get_membuf (&mb, NULL); + return *buf? 0 : gpg_error_from_syserror (); } + gpg_error_t result_xml_tag_data (struct result_xml_state *state, const char *data) { @@ -734,7 +861,7 @@ result_xml_tag_data (struct result_xml_state *state, const char *data) (*cb) (hook, ">", 1); state->had_data[state->next_tag - 1] = 2; - err = result_xml_escape(data, &buf); + err = result_xml_escape (data, &buf); if (err) return err;