Add delete-before-open=1 URI flag to the 'opfs' VFS to tell it to xDelete the db file before opening it, primarily to enable users to work around a corrupt db without having to reach into OPFS-specific APIs to remove the db file.

FossilOrigin-Name: e83f9788636f7f9bcca7d2a09620c13ab4eb83436d5b2946a827e48addf0267d

3 files changed, 47 insertions, 18 deletions

diff --git a/ext/wasm/api/sqlite3-opfs-async-proxy.js b/ext/wasm/api/sqlite3-opfs-async-proxy.js
index cafd296c6..58b8bcb23 100644
--- a/ext/wasm/api/sqlite3-opfs-async-proxy.js
+++ b/ext/wasm/api/sqlite3-opfs-async-proxy.js
@@ -562,6 +562,17 @@ const installAsyncProxy = function(self){
           wTimeEnd();
           return;
         }
+        if( state.opfsFlags.OPFS_UNLINK_BEFORE_OPEN & opfsFlags ){
+          //log("async proxy opfsFlags =",opfsFlags);
+          try{
+            await hDir.removeEntry(filenamePart);
+            //log("Unlinked",filename,hDir,filenamePart);
+          }
+          catch(e){
+            /* ignoring */
+            //warn("Ignoring failed Unlink of",filename,":",e);
+          }
+        }
         const hFile = await hDir.getFileHandle(filenamePart, {create});
         wTimeEnd();
         const fh = Object.assign(Object.create(null),{
diff --git a/ext/wasm/api/sqlite3-vfs-opfs.c-pp.js b/ext/wasm/api/sqlite3-vfs-opfs.c-pp.js
index f7fd951a4..65e39e5b5 100644
--- a/ext/wasm/api/sqlite3-vfs-opfs.c-pp.js
+++ b/ext/wasm/api/sqlite3-vfs-opfs.c-pp.js
@@ -423,11 +423,19 @@ const installOpfsVfs = function callee(options){
     });
     state.opfsFlags = Object.assign(Object.create(null),{
       /**
-         Flag for use with xOpen(). "opfs-unlock-asap=1" enables
-         this. See defaultUnlockAsap, below.
+         Flag for use with xOpen(). URI flag "opfs-unlock-asap=1"
+         enables this. See defaultUnlockAsap, below.
        */
       OPFS_UNLOCK_ASAP: 0x01,
       /**
+         Flag for use with xOpen(). URI flag "delete-before-open=1"
+         tells the VFS to delete the db file before attempting to open
+         it. This can be used, e.g., to replace a db which has been
+         corrupted (without forcing us to expose a delete/unlink()
+         function in the public API).
+      */
+      OPFS_UNLINK_BEFORE_OPEN: 0x02,
+      /**
          If true, any async routine which implicitly acquires a sync
          access handle (i.e. an OPFS lock) will release that locks at
          the end of the call which acquires it. If false, such
@@ -875,13 +883,17 @@ const installOpfsVfs = function callee(options){
         let opfsFlags = 0;
         if(0===zName){
           zName = randomFilename();
-        }else if('number'===typeof zName){
+        }else if(wasm.isPtr(zName)){
           if(capi.sqlite3_uri_boolean(zName, "opfs-unlock-asap", 0)){
             /* -----------------------^^^^^ MUST pass the untranslated
                C-string here. */
             opfsFlags |= state.opfsFlags.OPFS_UNLOCK_ASAP;
           }
+          if(capi.sqlite3_uri_boolean(zName, "delete-before-open", 0)){
+            opfsFlags |= state.opfsFlags.OPFS_UNLINK_BEFORE_OPEN;
+          }
           zName = wasm.cstrToJs(zName);
+          //warn("xOpen zName =",zName, "opfsFlags =",opfsFlags);
         }
         const fh = Object.create(null);
         fh.fid = pFile;
diff --git a/ext/wasm/tester1.c-pp.js b/ext/wasm/tester1.c-pp.js
index f8a022523..fdde98635 100644
--- a/ext/wasm/tester1.c-pp.js
+++ b/ext/wasm/tester1.c-pp.js
@@ -2888,18 +2888,17 @@ globalThis.sqlite3InitModule = sqlite3InitModule;
     .t({
       name: 'OPFS db sanity checks',
       test: async function(sqlite3){
+        T.assert(capi.sqlite3_vfs_find('opfs'));
+        const opfs = sqlite3.opfs;
         const filename = this.opfsDbFile = '/dir/sqlite3-tester1.db';
-        const pVfs = this.opfsVfs = capi.sqlite3_vfs_find('opfs');
-        T.assert(pVfs);
-        const unlink = this.opfsUnlink =
-              (fn=filename)=>{sqlite3.util.sqlite3__wasm_vfs_unlink(pVfs,fn)};
-        unlink();
-        let db = new sqlite3.oo1.OpfsDb(filename);
+        const fileUri = 'file://'+filename+'?delete-before-open=1';
+        const initSql = [
+          'create table p(a);',
+          'insert into p(a) values(1),(2),(3)'
+        ];
+        let db = new sqlite3.oo1.OpfsDb(fileUri);
         try {
-          db.exec([
-            'create table p(a);',
-            'insert into p(a) values(1),(2),(3)'
-          ]);
+          db.exec(initSql);
           T.assert(3 === db.selectValue('select count(*) from p'));
           db.close();
           db = new sqlite3.oo1.OpfsDb(filename);
@@ -2911,7 +2910,14 @@ globalThis.sqlite3InitModule = sqlite3InitModule;
                     && 0===this.opfsDbExport.byteLength % 512);
         }finally{
           db.close();
-          unlink();
+        }
+        T.assert(await opfs.entryExists(filename));
+        try {
+          db = new sqlite3.oo1.OpfsDb(fileUri);
+          db.exec(initSql) /* will throw if delete-before-open did not work */;
+          T.assert(3 === db.selectValue('select count(*) from p'));
+        }finally{
+          if(db) db.close();
         }
       }
     }/*OPFS db sanity checks*/)
@@ -2919,15 +2925,17 @@ globalThis.sqlite3InitModule = sqlite3InitModule;
       name: 'OPFS import',
       test: async function(sqlite3){
         let db;
+        const filename = this.opfsDbFile;
         try {
           const exp = this.opfsDbExport;
-          const filename = this.opfsDbFile;
           delete this.opfsDbExport;
           this.opfsImportSize = await sqlite3.oo1.OpfsDb.importDb(filename, exp);
           db = new sqlite3.oo1.OpfsDb(this.opfsDbFile);
           T.assert(6 === db.selectValue('select count(*) from p')).
             assert( this.opfsImportSize == exp.byteLength );
           db.close();
+          const unlink = this.opfsUnlink =
+                (fn=filename)=>sqlite3.util.sqlite3__wasm_vfs_unlink("opfs",fn);
           this.opfsUnlink(filename);
           T.assert(!(await sqlite3.opfs.entryExists(filename)));
           // Try again with a function as an input source:
@@ -2954,11 +2962,9 @@ globalThis.sqlite3InitModule = sqlite3InitModule;
       name: '(Internal-use) OPFS utility APIs',
       test: async function(sqlite3){
         const filename = this.opfsDbFile;
-        const pVfs = this.opfsVfs;
         const unlink = this.opfsUnlink;
-        T.assert(filename && pVfs && !!unlink);
+        T.assert(filename && !!unlink);
         delete this.opfsDbFile;
-        delete this.opfsVfs;
         delete this.opfsUnlink;
         /**************************************************************
            ATTENTION CLIENT-SIDE USERS: sqlite3.opfs is NOT intended