fix: allocate SQL on the heap in Database.run and Database.prepare

src/api.js

@@ -77,14 +77,9 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
     var sqlite3_exec = cwrap(
         "sqlite3_exec",
         "number",
-        ["number", "string", "number", "number", "number"]
+        ["number", "number", "number", "number", "number"]
     );
     var sqlite3_changes = cwrap("sqlite3_changes", "number", ["number"]);
-    var sqlite3_prepare_v2 = cwrap(
-        "sqlite3_prepare_v2",
-        "number",
-        ["number", "string", "number", "number", "number"]
-    );
     var sqlite3_sql = cwrap("sqlite3_sql", "string", ["number"]);
     var sqlite3_normalized_sql = cwrap(
         "sqlite3_normalized_sql",
@@ -869,7 +864,12 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
                 stmt.free();
             }
         } else {
-            this.handleError(sqlite3_exec(this.db, sql, 0, 0, apiTemp));
+            var sqlPtr = stringToNewUTF8(sql);
+            try {
+                this.handleError(sqlite3_exec(this.db, sqlPtr, 0, 0, apiTemp));
+            } finally {
+                _free(sqlPtr);
+            }
         }
         return this;
     };
@@ -1048,10 +1048,15 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
     @throws {String} SQLite error
      */
     Database.prototype.prepare = function prepare(sql, params) {
-        setValue(apiTemp, 0, "i32");
-        this.handleError(
-            sqlite3_prepare_v2(this.db, sql, -1, apiTemp, NULL)
-        );
+        var sqlPtr = stringToNewUTF8(sql);
+        try {
+            setValue(apiTemp, 0, "i32");
+            this.handleError(
+                sqlite3_prepare_v2_sqlptr(this.db, sqlPtr, -1, apiTemp, NULL)
+            );
+        } finally {
+            _free(sqlPtr);
+        }
         // pointer to a statement, or null
         var pStmt = getValue(apiTemp, "i32");
         if (pStmt === NULL) {

test/test_issue482.js

@@ -0,0 +1,45 @@
+// test for https://github.com/sql-js/sql.js/issues/482
+exports.test = function (sql, assert) {
+    "use strict";
+    // The WebAssembly stack is 5 MB, so SQL of this size cannot live on it
+    var text = "a".repeat(6 * 1024 * 1024);
+    var insert = "INSERT INTO t VALUES ('" + text + "', ?)";
+    var lengths = "SELECT length(a) FROM t";
+
+    var db = new sql.Database();
+    db.run("CREATE TABLE t (a, b)");
+
+    db.run("INSERT INTO t VALUES ('" + text + "', 1)");
+    db.run(insert, [2]);
+    var stmt = db.prepare(insert, [3]);
+    stmt.step();
+    stmt.free();
+
+    assert.deepEqual(
+        db.exec(lengths)[0].values,
+        [[text.length], [text.length], [text.length]],
+        "long SQL passed to run, run with params and prepare is executed"
+    );
+    assert.deepEqual(
+        db.exec("SELECT b FROM t")[0].values,
+        [[1], [2], [3]],
+        "database is still usable after long SQL"
+    );
+
+    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 issue482': function (assert) {
+                exports.test(sql, assert);
+            }
+        });
+    }).catch((e) => {
+        console.error(e);
+        assert.fail(e);
+    });
+}