Merge r1485409:

  Be more clever when allocating memory for log item to be escaped.
  This should be faster and save about 70-100 bytes in the request pool with the default config.

Reviewed by: minfrin, rjung, rpluem

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1510044 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/STATUS b/STATUS
index c4296e1ce606d9643471fc9262f4fa00fb96dd57..2c4491f7c876f1f12b64f5d0a6eb1e461d9c8801 100644 (file)
--- a/STATUS
+++ b/STATUS
@@ -97,19 +97,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
   
-  * core: speed up (for common cases) and reduce memory usage of ap_escape_logitem
-    This should save 70-100 bytes in the request pool for a default config.
-    trunk patch: http://svn.apache.org/r1485409
-    2.4.x patch: http://svn.apache.org/r1485723
-    2.2.x patch: trunk works
-    +1: minfrin, rjung, rpluem
-    wrowe wonders why we copy and don't simply return the identity on no-change
-    rjung: From an API point of view the function - as well as the html escape functions
-           - takes a const char* and returns a plain char *. So a consumer would be free
-           to write to the returned string. There's no such place in httpd code I can
-           find but we can't rule it out for foreign modules. We could fix the signature
-           (returning const char *) in trunk but not for 2.2 ad 2.4. 
-
   * mod_dav; Teeny patch to fix #55304
     trunk: http://svn.apache.org/r1506714
     +1: gstein, wrowe, rpluem

diff --git a/server/util.c b/server/util.c
index f1fb2550f15e70ada26b5b0743e91366ef4ab690..5dee87fd22925475ebfe5f37cf45fe568559aa98 100644 (file)
--- a/server/util.c
+++ b/server/util.c
@@ -1845,16 +1845,33 @@ AP_DECLARE(char *) ap_escape_logitem(apr_pool_t *p, const char *str)
     char *ret;
     unsigned char *d;
     const unsigned char *s;
+    apr_size_t length, escapes = 0;
 
     if (!str) {
         return NULL;
     }
 
-    ret = apr_palloc(p, 4 * strlen(str) + 1); /* Be safe */
+    /* Compute how many characters need to be escaped */
+    s = (const unsigned char *)str;
+    for (; *s; ++s) {
+        if (TEST_CHAR(*s, T_ESCAPE_LOGITEM)) {
+            escapes++;
+        }
+    }
+    
+    /* Compute the length of the input string, including NULL */
+    length = s - (const unsigned char *)str + 1;
+    
+    /* Fast path: nothing to escape */
+    if (escapes == 0) {
+        return apr_pmemdup(p, str, length);
+    }
+    
+    /* Each escaped character needs up to 3 extra bytes (0 --> \x00) */
+    ret = apr_palloc(p, length + 3 * escapes);
     d = (unsigned char *)ret;
     s = (const unsigned char *)str;
     for (; *s; ++s) {
-
         if (TEST_CHAR(*s, T_ESCAPE_LOGITEM)) {
             *d++ = '\\';
             switch(*s) {