[PATCH v4 1/5] util: Factor out boolean term quoting routine
Jani Nikula
jani at nikula.org
Thu Jan 3 08:48:54 PST 2013
On Mon, 31 Dec 2012, Austin Clements <amdragon at MIT.EDU> wrote:
> From: Austin Clements <amdragon at MIT.EDU>
>
> This is now a generic boolean term quoting function. It performs
> minimal quoting to produce user-friendly queries.
>
> This could live in tag-util as well, but it is really nothing specific
> to tags (although the conventions are specific to Xapian).
>
> The API is changed from "caller-allocates" to "readline-like". The
> scan for max tag length is pushed down into the quoting routine.
> Furthermore, this now combines the term prefix with the quoted term;
> arguably this is just as easy to do in the caller, but this will
> nicely parallel the boolean term parsing function to be introduced
> shortly.
>
> This is an amalgamation of code written by David Bremner and myself.
> ---
> notmuch-tag.c | 48 ++++++++++++---------------------------
> util/string-util.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> util/string-util.h | 14 ++++++++++++
> 3 files changed, 92 insertions(+), 34 deletions(-)
>
> diff --git a/notmuch-tag.c b/notmuch-tag.c
> index 88d559b..fc9d43a 100644
> --- a/notmuch-tag.c
> +++ b/notmuch-tag.c
> @@ -19,6 +19,7 @@
> */
>
> #include "notmuch-client.h"
> +#include "string-util.h"
>
> static volatile sig_atomic_t interrupted;
>
> @@ -35,25 +36,6 @@ handle_sigint (unused (int sig))
> interrupted = 1;
> }
>
> -static char *
> -_escape_tag (char *buf, const char *tag)
> -{
> - const char *in = tag;
> - char *out = buf;
> -
> - /* Boolean terms surrounded by double quotes can contain any
> - * character. Double quotes are quoted by doubling them. */
> - *out++ = '"';
> - while (*in) {
> - if (*in == '"')
> - *out++ = '"';
> - *out++ = *in++;
> - }
> - *out++ = '"';
> - *out = 0;
> - return buf;
> -}
> -
> typedef struct {
> const char *tag;
> notmuch_bool_t remove;
> @@ -71,25 +53,16 @@ _optimize_tag_query (void *ctx, const char *orig_query_string,
> * parenthesize and the exclusion part of the query must not use
> * the '-' operator (though the NOT operator is fine). */
>
> - char *escaped, *query_string;
> + char *escaped = NULL;
> + size_t escaped_len = 0;
> + char *query_string;
> const char *join = "";
> - int i;
> - unsigned int max_tag_len = 0;
> + size_t i;
>
> /* Don't optimize if there are no tag changes. */
> if (tag_ops[0].tag == NULL)
> return talloc_strdup (ctx, orig_query_string);
>
> - /* Allocate a buffer for escaping tags. This is large enough to
> - * hold a fully escaped tag with every character doubled plus
> - * enclosing quotes and a NUL. */
> - for (i = 0; tag_ops[i].tag; i++)
> - if (strlen (tag_ops[i].tag) > max_tag_len)
> - max_tag_len = strlen (tag_ops[i].tag);
> - escaped = talloc_array (ctx, char, max_tag_len * 2 + 3);
> - if (! escaped)
> - return NULL;
> -
> /* Build the new query string */
> if (strcmp (orig_query_string, "*") == 0)
> query_string = talloc_strdup (ctx, "(");
> @@ -97,10 +70,17 @@ _optimize_tag_query (void *ctx, const char *orig_query_string,
> query_string = talloc_asprintf (ctx, "( %s ) and (", orig_query_string);
>
> for (i = 0; tag_ops[i].tag && query_string; i++) {
> + /* XXX in case of OOM, query_string will be deallocated when
> + * ctx is, which might be at shutdown */
> + if (make_boolean_term (ctx,
> + "tag", tag_ops[i].tag,
> + &escaped, &escaped_len))
> + return NULL;
> +
> query_string = talloc_asprintf_append_buffer (
> - query_string, "%s%stag:%s", join,
> + query_string, "%s%s%s", join,
> tag_ops[i].remove ? "" : "not ",
> - _escape_tag (escaped, tag_ops[i].tag));
> + escaped);
> join = " or ";
> }
>
> diff --git a/util/string-util.c b/util/string-util.c
> index 44f8cd3..e4bea21 100644
> --- a/util/string-util.c
> +++ b/util/string-util.c
> @@ -20,6 +20,7 @@
>
>
> #include "string-util.h"
> +#include "talloc.h"
>
> char *
> strtok_len (char *s, const char *delim, size_t *len)
> @@ -32,3 +33,66 @@ strtok_len (char *s, const char *delim, size_t *len)
>
> return *len ? s : NULL;
> }
> +
> +int
> +make_boolean_term (void *ctx, const char *prefix, const char *term,
> + char **buf, size_t *len)
> +{
> + const char *in;
> + char *out;
> + size_t needed = 3;
> + int need_quoting = 0;
> +
> + /* Do we need quoting? To be paranoid, we quote anything
> + * containing a quote, even though it only matters at the
> + * beginning, and anything containing non-ASCII text. */
> + for (in = term; *in && !need_quoting; in++)
> + if (*in <= ' ' || *in == ')' || *in == '"' || (unsigned char)*in > 127)
Should that be *in >= 127?
Otherwise LGTM.
Jani.
> + need_quoting = 1;
> +
> + if (need_quoting)
> + for (in = term; *in; in++)
> + needed += (*in == '"') ? 2 : 1;
> + else
> + needed = strlen (term) + 1;
> +
> + /* Reserve space for the prefix */
> + if (prefix)
> + needed += strlen (prefix) + 1;
> +
> + if ((*buf == NULL) || (needed > *len)) {
> + *len = 2 * needed;
> + *buf = talloc_realloc (ctx, *buf, char, *len);
> + }
> +
> + if (! *buf)
> + return 1;
> +
> + out = *buf;
> +
> + /* Copy in the prefix */
> + if (prefix) {
> + strcpy (out, prefix);
> + out += strlen (prefix);
> + *out++ = ':';
> + }
> +
> + if (! need_quoting) {
> + strcpy (out, term);
> + return 0;
> + }
> +
> + /* Quote term by enclosing it in double quotes and doubling any
> + * internal double quotes. */
> + *out++ = '"';
> + in = term;
> + while (*in) {
> + if (*in == '"')
> + *out++ = '"';
> + *out++ = *in++;
> + }
> + *out++ = '"';
> + *out = '\0';
> +
> + return 0;
> +}
> diff --git a/util/string-util.h b/util/string-util.h
> index ac7676c..b8844a3 100644
> --- a/util/string-util.h
> +++ b/util/string-util.h
> @@ -19,4 +19,18 @@
>
> char *strtok_len (char *s, const char *delim, size_t *len);
>
> +/* Construct a boolean term query with the specified prefix (e.g.,
> + * "id") and search term, quoting term as necessary. Specifically, if
> + * term contains any non-printable ASCII characters, non-ASCII
> + * characters, close parenthesis or double quotes, it will be enclosed
> + * in double quotes and any internal double quotes will be doubled
> + * (e.g. a"b -> "a""b"). The result will be a valid notmuch query and
> + * can be parsed by parse_boolean_term.
> + *
> + * Output is into buf; it may be talloc_realloced.
> + * Return: 0 on success, non-zero on memory allocation failure.
> + */
> +int make_boolean_term (void *talloc_ctx, const char *prefix, const char *term,
> + char **buf, size_t *len);
> +
> #endif
> --
> 1.7.10.4
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