refactor(executor): use file api

Refers to #215

lib/executors/versioned/v1.js

@@ -1,43 +1,39 @@
-var log = require('db-migrate-shared').log;
-var Promise = require('bluebird');
+const Promise = require('bluebird');
+const { maybePromise } = require('../../temputils.js');
 
 const execUnit = {
-  up: function (context, driver, execUnit) {
+  up: function (context, driver, file) {
     return context.driver
       .startMigration()
       .then(() => {
-        var setup = execUnit.setup;
+        const _file = file.get();
 
-        if (typeof setup === 'function') {
-          setup(context.internals.execUnitOptions, context.seedLink);
+        if (typeof _file.setup === 'function') {
+          _file.setup(context.internals.fileOptions, context.seedLink);
         }
 
-        return execUnit.up();
+        return maybePromise(_file.up);
       })
       .then(() => {
-        return Promise.promisify(context.writeexecUnitRecord.bind(context))(
-          execUnit
-        );
+        return Promise.promisify(context.writeRecord.bind(context))(file);
       })
       .then(context.driver.endMigration.bind(context.driver));
   },
 
-  down: function (context, driver, execUnit) {
+  down: function (context, driver, file) {
     return driver
       .startMigration()
       .then(() => {
-        var setup = execUnit.setup;
+        const _file = file.get();
 
-        if (typeof setup === 'function') {
-          setup(context.internals.execUnitOptions, context.seedLink);
+        if (typeof _file.setup === 'function') {
+          _file.setup(context.internals.fileOptions, context.seedLink);
         }
 
-        return execUnit.down();
+        return maybePromise(_file.down);
       })
       .then(() => {
-        return Promise.promisify(context.deleteexecUnitRecord.bind(context))(
-          execUnit
-        );
+        return Promise.promisify(context.deleteRecord.bind(context))(file);
       })
       .then(context.driver.endMigration.bind(context.driver));
   }

lib/temputils.js

@@ -0,0 +1,54 @@
+'use strict';
+
+function isPromise (probe) {
+  return (
+    probe instanceof Promise ||
+    (probe &&
+      probe.then &&
+      probe.constructor &&
+      probe.constructor.name === 'Promise')
+  );
+}
+
+function maybePromise (context, action, params) {
+  let cbExecuted = false;
+
+  return new Promise((resolve, reject) => {
+    const r = err => {
+      if (cbExecuted === false) {
+        cbExecuted = true;
+
+        if (err) {
+          reject(err);
+        } else {
+          resolve();
+        }
+      }
+    };
+
+    params[params.length++] = r;
+
+    if (typeof action === 'function') action = action.apply(context, params);
+    else action = Promise.resolve();
+
+    if (isPromise(action)) {
+      action
+        .then(() => {
+          if (cbExecuted === false) {
+            cbExecuted = true;
+            resolve();
+          }
+        })
+        .catch(err => {
+          if (cbExecuted === false) {
+            cbExecuted = true;
+            reject(err);
+          }
+        });
+    }
+  });
+}
+
+module.exports = {
+  maybePromise: maybePromise
+};