On Sat, 29 Dec 2012, Tomi Ollila <tomi.ollila at iki.fi> wrote:
> On Fri, Dec 28 2012, Austin Clements <amdragon at MIT.EDU> wrote:
>
>> This parses the subset of Xapian's boolean term quoting rules that are
>> used by make_boolean_term. This is provided as a generic string
>> utility, but will be used shortly in notmuch restore to parse and
>> optimize for ID queries.
>> ---
>> util/string-util.c | 55
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>> util/string-util.h | 11 +++++++++++
>> 2 files changed, 66 insertions(+)
>>
>> diff --git a/util/string-util.c b/util/string-util.c
>> index e4bea21..83b4953 100644
>> --- a/util/string-util.c
>> +++ b/util/string-util.c
>> @@ -96,3 +96,58 @@ make_boolean_term (void *ctx, const char *prefix, const
>> char *term,
>>
>> return 0;
>> }
>> +
>> +int
>> +parse_boolean_term (void *ctx, const char *str,
>> + char **prefix_out, char **term_out)
>> +{
>> + *prefix_out = *term_out = NULL;
>> +
>> + /* Parse prefix */
>> + const char *pos = strchr (str, ':');
>> + if (! pos)
>> + goto FAIL;
>> + *prefix_out = talloc_strndup (ctx, str, pos - str);
>> + ++pos;
>> +
>> + /* Implement de-quoting compatible with make_boolean_term. */
>> + if (*pos == '"') {
>> + char *out = talloc_array (ctx, char, strlen (pos));
>> + int closed = 0;
>> + *term_out = out;
>> + /* Skip the opening quote, find the closing quote, and
>> + * un-double doubled internal quotes. */
>> + for (++pos; *pos; ) {
>> + if (*pos == '"') {
>> + ++pos;
>> + if (*pos != '"') {
>> + /* Found the closing quote. */
>> + closed = 1;
>> + break;
>> + }
>> + }
>> + *out++ = *pos++;
>> + }
>> + /* Did the term terminate without a closing quote or is there
>> + * trailing text after the closing quote? */
>> + if (!closed || *pos)
>> + goto FAIL;
>> + *out = '\0';
>> + } else {
>> + const char *start = pos;
>> + /* Check for text after the boolean term. */
>> + while (*pos > ' ' && *pos != ')')
>> + ++pos;
>> + if (*pos)
>> + goto FAIL;
>
> Mark pointed out a good case about trailing whitespace -- It would be nice
> if the core were lenient for such cases. I personally remember once wasting
> hours of work by just failing to notice trailing whitespace in one system
> so this subject is sensitive to me...
Will do.
> Another thing I saw earlyer today: make_boolean_term() checks
>
> if (*in <= ' ' || *in == ')' || *in == '"' || (unsigned char)*in > 127)
>
> but here the check is only
>
> while (*pos > ' ' && *pos != ')')
>
> I wonder whether it matters...
This is correct in a conservative way. We quote things that we don't
strictly need to quote (for example, a double quote in the middle of a
term doesn't actually require the term to be quoted, but we do anyway),
but we look for the end of an unquoted term in exactly the same way
Xapian does.
> Everyting else looks good to me.
>
>
> Tomi
>
>> + /* No trailing text; dup the string so the caller can free
>> + * it. */
>> + *term_out = talloc_strdup (ctx, start);
>> + }
>> + return 0;
>> +
>> + FAIL:
>> + talloc_free (*prefix_out);
>> + talloc_free (*term_out);
>> + return 1;
>> +}
>> diff --git a/util/string-util.h b/util/string-util.h
>> index b8844a3..43d49d0 100644
>> --- a/util/string-util.h
>> +++ b/util/string-util.h
>> @@ -33,4 +33,15 @@ char *strtok_len (char *s, const char *delim, size_t
>> *len);
>> int make_boolean_term (void *talloc_ctx, const char *prefix, const char
>> *term,
>> char **buf, size_t *len);
>>
>> +/* Parse a boolean term query produced by make_boolean_term, returning
>> + * the prefix in *prefix_out and the term in *term_out. *prefix_out
>> + * and *term_out will be talloc'd with context ctx.
>> + *
>> + * Return: 0 on success, non-zero on parse error (including trailing
>> + * data in str).
>> + */
>> +int
>> +parse_boolean_term (void *ctx, const char *str,
>> + char **prefix_out, char **term_out);
>> +
>> #endif
>> --
>> 1.7.10.4
>>
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