[WIP]Add support for NODEFS

Makefile

@@ -37,7 +37,8 @@ EMFLAGS = \
 	-s EXPORTED_RUNTIME_METHODS=@src/exported_runtime_methods.json \
 	-s SINGLE_FILE=0 \
 	-s NODEJS_CATCH_EXIT=0 \
-	-s NODEJS_CATCH_REJECTION=0
+	-s NODEJS_CATCH_REJECTION=0 \
+	-l nodefs.js
 
 EMFLAGS_ASM = \
 	-s WASM=0

src/api.js

@@ -176,10 +176,9 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
             "number",
             "number",
             "number",
-            "number",
-            "number",
-            "number",
-            "number"
+
+
+
         ]
     );
     var sqlite3_value_type = cwrap("sqlite3_value_type", "number", ["number"]);
@@ -819,14 +818,21 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
     * @memberof module:SqlJs
     * Open a new database either by creating a new one or opening an existing
     * one stored in the byte array passed in first argument
-    * @param {Array<number>} data An array of bytes representing
+    * @param {Array<number>|string} data An array of bytes representing,
+    * or a string for mapped file name
     * an SQLite database file
     */
     function Database(data) {
-        this.filename = "dbfile_" + (0xffffffff * Math.random() >>> 0);
-        if (data != null) {
-            FS.createDataFile("/", this.filename, data, true, true);
+        if (data != null && typeof data === "string") {
+            this.filename = data;
+            this.filetype = "FS";
+        } else {
+            this.filename = "dbfile_" + (0xffffffff * Math.random() >>> 0);
+            if (data != null) {
+                FS.createDataFile("/", this.filename, data, true, true);
+            }
         }
+
         this.handleError(sqlite3_open(this.filename, apiTemp));
         this.db = getValue(apiTemp, "i32");
         registerExtensionFunctions(this.db);
@@ -1113,7 +1119,9 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
         Object.values(this.functions).forEach(removeFunction);
         this.functions = {};
         this.handleError(sqlite3_close_v2(this.db));
-        FS.unlink("/" + this.filename);
+        if (this.filetype !== "FS") {
+            FS.unlink("/" + this.filename);
+        }
         this.db = null;
     };
 
@@ -1250,6 +1258,27 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
         return this;
     };
 
+    var vfs = Module["FS"];
+
+    /** Create database instance
+    @param {string} vdir directory name to mount for virtual fs
+    @param {string} osdir system directory to mount
+     */
+    Module["mount"] = function mount(vdir, osdir) {
+        if (vfs.mayCreate(vdir)) {
+            vfs.mkdir(vdir);
+        }
+        vfs.mount(vfs.filesystems["NODEFS"], { root: osdir }, vdir);
+    };
+
+    var mountpoints = Module["mountpoints"];
+    if (mountpoints) {
+        Array.prototype.forEach.call(Object.keys(mountpoints),
+            function mount(mp) {
+                Module["mount"](mp, mountpoints[mp]);
+            });
+    }
+
     /** Register a custom aggregate with SQLite
       @example <caption>Register a custom sum function</caption>
         db.create_aggregate("js_sum", {

src/exported_runtime_methods.json

@@ -3,7 +3,8 @@
 "stackAlloc",
 "stackSave",
 "stackRestore",
-"UTF8ToString",
+"FS",
+"UTF8ToString"
 
 "allocate",
 "ALLOC_NORMAL",

test/test_nodefs.js

@@ -0,0 +1,35 @@
+exports.test = function(SQL, assert) {
+	//Node filesystem module - You know that.
+	var fs = require('fs');
+
+	//Ditto, path module
+	var path = require('path');
+
+	SQL.mount('/nfs', __dirname);
+
+	//Works
+	var db = new SQL.Database('/nfs/test.sqlite');
+
+	//[{"columns":["id","content"],"values":[["0","hello"],["1","world"]]}]
+	var res = db.exec("SELECT * FROM test WHERE id = 0");
+	assert.deepEqual(res,
+									[{"columns":["id","content"],"values":[[0,"hello"]]}],
+									"One should be able to read the mounted file from disk");
+	db.close();
+}
+
+if (module == require.main) {
+	const target_file = process.argv[2];
+  const sql_loader = require('./load_sql_lib');
+  sql_loader(target_file).then((sql)=>{
+    require('test').run({
+      'test node file': function(assert){
+        exports.test(sql, assert);
+      }
+    });
+  })
+  .catch((e)=>{
+    console.error(e);
+    assert.fail(e);
+  });
+}