short circuit && and || evaluation. For backwards compat this is only

possible if there's no regex on the short circuited side (since it fills
in the backref data). The user may optimize this by putting the regex
onto the left side of the operator.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@101097 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/modules/filters/mod_include.c b/modules/filters/mod_include.c
index e4290ed1dd21210354cb976b980d7dd049ee5fc1..a31941f182711141a11fd444b821241a050ffebd 100644 (file)
--- a/modules/filters/mod_include.c
+++ b/modules/filters/mod_include.c
@@ -1123,7 +1123,8 @@ static int parse_expr(include_ctx_t *ctx, const char *expr, int *was_error)
     const char* buffer;
     const char *parse = expr;
     int retval = 0, was_unmatched = 0;
-    
+    unsigned regex = 0;
+
     *was_error = 0;
 
     if (!parse) {
@@ -1196,6 +1197,7 @@ static int parse_expr(include_ctx_t *ctx, const char *expr, int *was_error)
             case TOKEN_NOT:
                 new->parent = current;
                 current = current->right = new;
+                ++regex;
                 break;
 
             default:
@@ -1438,39 +1440,54 @@ static int parse_expr(include_ctx_t *ctx, const char *expr, int *was_error)
                     continue;
                 }
             }
-            if (!current->right->done) {
-                switch (current->right->token.type) {
-                case TOKEN_STRING:
-                    buffer = ap_ssi_parse_string(ctx,
-                                                 current->right->token.value,
-                                                 NULL, 0, SSI_EXPAND_DROP_NAME);
 
-                    current->right->token.value = buffer;
-                    current->right->value = !!*current->right->token.value;
-                    current->right->done = 1;
-                    break;
+            /* 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
+                                                                  ? '1' : '0'));
+                DEBUG_PRINTF((ctx, "     Right: short circuited\n"));
 
-                default:
-                    current = current->right;
-                    continue;
-                }
+                current->value = current->left->value;
             }
+            else {
+                if (!current->right->done) {
+                    switch (current->right->token.type) {
+                    case TOKEN_STRING:
+                        buffer = ap_ssi_parse_string(ctx,
+                                                     current->right->token.value,
+                                                     NULL, 0,
+                                                     SSI_EXPAND_DROP_NAME);
+
+                        current->right->token.value = buffer;
+                        current->right->value = !!*current->right->token.value;
+                        current->right->done = 1;
+                        break;
+
+                    default:
+                        current = current->right;
+                        continue;
+                    }
+                }
 
-            DEBUG_PRINTF((ctx, "     Left: %c\n", current->left->value
+                DEBUG_PRINTF((ctx, "     Left: %c\n", current->left->value
                                                                   ? '1' : '0'));
-            DEBUG_PRINTF((ctx, "     Right: %c\n", current->right->value
+                DEBUG_PRINTF((ctx, "     Right: %c\n", current->right->value
                                                                   ? '1' : '0'));
 
-            if (current->token.type == TOKEN_AND) {
-                current->value = current->left->value && current->right->value;
-            }
-            else {
-                current->value = current->left->value || current->right->value;
+                if (current->token.type == TOKEN_AND) {
+                    current->value = current->left->value &&
+                                     current->right->value;
+                }
+                else {
+                    current->value = current->left->value ||
+                                     current->right->value;
+                }
             }
 
             DEBUG_PRINTF((ctx, "     Returning %c\n", current->value
                                                                   ? '1' : '0'));
-
             current->done = 1;
             current = current->parent;
             break;
@@ -1505,6 +1522,7 @@ static int parse_expr(include_ctx_t *ctx, const char *expr, int *was_error)
 
                 current->value = re_check(ctx, current->left->token.value,
                                           current->right->token.value);
+                --regex;
             }
             else {
                 DEBUG_PRINTF((ctx, "     Compare (%s) with (%s)\n",