* Rainer Jung wrote:
> On 27.03.2013 22:57, [email protected] wrote:
> > Author: jailletc36
> > Date: Wed Mar 27 21:57:44 2013
> > New Revision: 1461869
> >
> > URL: http://svn.apache.org/r1461869
> > Log:
> > Be more clever when allocating memory for log item to be escaped.
> > This should save about 70-100 bytes in the request pool with the
> > default config.
> >
> > Modified:
> > httpd/httpd/trunk/server/util.c
> >
> > Modified: httpd/httpd/trunk/server/util.c
> > URL:
> > http://svn.apache.org/viewvc/httpd/httpd/trunk/server/util.c?rev=146186
> >9&r1=1461868&r2=1461869&view=diff
> > =======================================================================
> >======= --- httpd/httpd/trunk/server/util.c (original)
> > +++ httpd/httpd/trunk/server/util.c Wed Mar 27 21:57:44 2013
> > @@ -1850,12 +1850,26 @@ AP_DECLARE(char *) ap_escape_logitem(apr
> > char *ret;
> > unsigned char *d;
> > const unsigned char *s;
> > + int length = 0;
> >
> > if (!str) {
> > return NULL;
> > }
> >
> > - ret = apr_palloc(p, 4 * strlen(str) + 1); /* Be safe */
> > + /* First, compute the space needed for the escaped string.
> > + * This could be tweaked a bit for '\b', '\n'... These characters
> > + * should not be common, so do not bother. */
> > + s = (const unsigned char *)str;
> > + for (; *s; ++s) {
> > + if (TEST_CHAR(*s, T_ESCAPE_LOGITEM)) {
> > + length += 4; /* for '\\' + c2x() */
> > + }
> > + else {
> > + length++;
> > + }
> > + }
> > +
> > + ret = apr_palloc(p, length + 1);
> > d = (unsigned char *)ret;
>
> Here we treat CPU against memory. AFAIK this function is in the hot code
> path, because it is used for many of the fields used in the default
> access log format and also in many custom ones. All other uses seem to
> be either trace log messages, some (few) error log messages and
> mod_status output. For those cases I think neither the CPU nor the
> Memory differences are important.
>
> In the access log case it seems the typical fields which are run through
> ap_escape_logitem() should rarely contain characters to escape. So an
> alternative strategy would be to simply copy the string if we don't find
> a character to escape. The second check for each char is not necessary
> then.
>
> A quick draft patch is at
>
> http://people.apache.org/~rjung/patches/ap_escape_logitem_enhanced.patch
+ ret = apr_palloc(p, length + 3 * escapes);
It should be still 4 * escapes ('\xHH').
nd
--
Das, was ich nicht kenne, spielt stückzahlmäßig *keine* Rolle.
-- Helmut Schellong in dclc
