From: André Malo <nd@apache.org>
Date: Tue, 26 Aug 2003 00:32:03 +0000 (+0000)
Subject: since our parse tree is left-weighted, the short circuit evaluation
X-Git-Tag: pre_ajp_proxy~1208
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1830a08c2f97365c0f45c73a0fda4a33a74afb21;p=apache

since our parse tree is left-weighted, the short circuit evaluation
is way more useful if we short circuit the left side. So evaluate
the right side first. This, however, reverses my statement about
regex optimization (you have to put them onto the right side of an
&& or || operator to get a chance that the left side will be cutted).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@101105 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/modules/filters/mod_include.c b/modules/filters/mod_include.c
index 53e0d3f4f4..b210c891b5 100644
--- a/modules/filters/mod_include.c
+++ b/modules/filters/mod_include.c
@@ -1365,50 +1365,51 @@ static int parse_expr(include_ctx_t *ctx, const char *expr, int *was_error)
                 *was_error = 1;
                 return retval;
             }
-            if (!current->left->done) {
-                switch (current->left->token.type) {
+
+            if (!current->right->done) {
+                switch (current->right->token.type) {
                 case TOKEN_STRING:
                     buffer = ap_ssi_parse_string(ctx,
-                                                 current->left->token.value,
+                                                 current->right->token.value,
                                                  NULL, 0, SSI_EXPAND_DROP_NAME);
 
-                    current->left->token.value = buffer;
-                    current->left->value = !!*current->left->token.value;
-                    current->left->done = 1;
+                    current->right->token.value = buffer;
+                    current->right->value = !!*current->right->token.value;
+                    current->right->done = 1;
                     break;
 
                 default:
-                    current = current->left;
+                    current = current->right;
                     continue;
                 }
             }
 
             /* short circuit evaluation */
-            if (!current->right->done && !regex &&
-                ((current->token.type == TOKEN_AND && !current->left->value) ||
-                (current->token.type == TOKEN_OR && current->left->value))) {
-                DEBUG_PRINTF((ctx, "     Left: %c\n", current->left->value
+            if (!current->left->done && !regex &&
+                ((current->token.type == TOKEN_AND && !current->right->value) ||
+                (current->token.type == TOKEN_OR && current->right->value))) {
+                DEBUG_PRINTF((ctx, "     Left: short circuited\n"));
+                DEBUG_PRINTF((ctx, "     Right: %c\n", current->right->value
                                                                   ? '1' : '0'));
-                DEBUG_PRINTF((ctx, "     Right: short circuited\n"));
 
-                current->value = current->left->value;
+                current->value = current->right->value;
             }
             else {
-                if (!current->right->done) {
-                    switch (current->right->token.type) {
+                if (!current->left->done) {
+                    switch (current->left->token.type) {
                     case TOKEN_STRING:
                         buffer = ap_ssi_parse_string(ctx,
-                                                     current->right->token.value,
+                                                     current->left->token.value,
                                                      NULL, 0,
                                                      SSI_EXPAND_DROP_NAME);
 
-                        current->right->token.value = buffer;
-                        current->right->value = !!*current->right->token.value;
-                        current->right->done = 1;
+                        current->left->token.value = buffer;
+                        current->left->value = !!*current->left->token.value;
+                        current->left->done = 1;
                         break;
 
                     default:
-                        current = current->right;
+                        current = current->left;
                         continue;
                     }
                 }