Optimize VFS search.

sqlite3/vfs.c

@@ -90,22 +90,25 @@ int localtime_s(struct tm *const pTm, time_t const *const pTime) {
 sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName) {
   if (zVfsName) {
     static sqlite3_vfs *go_vfs_list;
-    sqlite3_vfs *found = NULL;
-    for (sqlite3_vfs **next = &go_vfs_list; *next;) {
-      sqlite3_vfs *it = *next;
+
+    for (sqlite3_vfs *it = go_vfs_list; it; it = it->pNext) {
+      if (!strcmp(zVfsName, it->zName) && go_vfs_find(it->zName)) {
+        return it;
+      }
+    }
+
+    for (sqlite3_vfs **ptr = &go_vfs_list; *ptr;) {
+      sqlite3_vfs *it = *ptr;
       if (go_vfs_find(it->zName)) {
-        if (!strcmp(zVfsName, it->zName)) found = it;
-        next = &it->pNext;
+        ptr = &it->pNext;
       } else {
-        *next = it->pNext;
+        *ptr = it->pNext;
         free(it);
       }
     }
-    if (found) {
-      return found;
-    }
+
     if (go_vfs_find(zVfsName)) {
-      sqlite3_vfs *prev = go_vfs_list;
+      sqlite3_vfs *head = go_vfs_list;
       go_vfs_list = malloc(sizeof(sqlite3_vfs) + strlen(zVfsName) + 1);
       char *name = (char *)(go_vfs_list + 1);
       strcpy(name, zVfsName);
@@ -114,7 +117,7 @@ sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName) {
           .szOsFile = sizeof(struct go_file),
           .mxPathname = 512,
           .zName = name,
-          .pNext = prev,
+          .pNext = head,
 
           .xOpen = go_open_wrapper,
           .xDelete = go_delete,

vfs/tests/mptest/testdata/mptest.wasm.bz2

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:816ddd36a255d2b3995f75924bdebd9dc7c4378eeccbe28176751434cfb788ca
-size 508404
+oid sha256:da493a827d5b2985ba80d7425092a891311633d6c80c559119f87609d0f0e02a
+size 508796

vfs/tests/speedtest1/testdata/speedtest1.wasm.bz2

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:c0c551f14aeb338ab652f2bded33ba58188b76f2cb24ca076576c968341f841e
-size 523315
+oid sha256:c5ffb1dc0f046bb7e4ea4cd992e1d625c05c7d5cf33c78edc5a2155eb3d3c097
+size 523393