Add scratchpad/test app for WASMFS/OPFS running in the main window thread. Enable WASMFS by default in the library build.

FossilOrigin-Name: ae24ac0f7dd9e12a40de0f6ccd61a16f010804da454085f886c217cc600cdba4

ext/wasm/scratchpad-opfs-main.js

@@ -0,0 +1,73 @@
+/*
+  2022-05-22
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  A basic test script for sqlite3-api.js. This file must be run in
+  main JS thread and sqlite3.js must have been loaded before it.
+*/
+'use strict';
+(function(){
+  const toss = function(...args){throw new Error(args.join(' '))};
+  const log = console.log.bind(console),
+        warn = console.warn.bind(console),
+        error = console.error.bind(console);
+
+  const stdout = log;
+  const stderr = error;
+
+  const test1 = function(db){
+    db.execMulti("create table if not exists t(a);")
+      .callInTransaction(function(db){
+        db.prepare("insert into t(a) values(?)")
+          .bind(new Date().getTime())
+          .stepFinalize();
+        stdout("Number of values in table t:",
+            db.selectValue("select count(*) from t"));
+      });
+  };
+
+  const runTests = function(Module){
+    //stdout("Module",Module);
+    self._MODULE = Module /* this is only to facilitate testing from the console */;
+    const sqlite3 = Module.sqlite3,
+          capi = sqlite3.capi,
+          oo = sqlite3.oo1,
+          wasm = capi.wasm;
+    stdout("Loaded sqlite3:",capi.sqlite3_libversion(), capi.sqlite3_sourceid());
+    const persistentDir = capi.sqlite3_web_persistent_dir();
+    if(persistentDir){
+      stdout("Persistent storage dir:",persistentDir);
+    }else{
+      stderr("No persistent storage available.");
+    }
+    const startTime = performance.now();
+    let db;
+    try {
+      db = new oo.DB(persistentDir+'/foo.db');
+      stdout("DB filename:",db.filename,db.fileName());
+      const banner1 = '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>',
+            banner2 = '<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<';
+      [
+        test1
+      ].forEach((f)=>{
+        const n = performance.now();
+        stdout(banner1,"Running",f.name+"()...");
+        f(db, sqlite3, Module);
+        stdout(banner2,f.name+"() took ",(performance.now() - n),"ms");
+      });
+    }finally{
+      if(db) db.close();
+    }
+    stdout("Total test time:",(performance.now() - startTime),"ms");
+  };
+
+  sqlite3InitModule(self.sqlite3TestModule).then(runTests);
+})();