Generate script: Don't write .cc or .h files if unchanged

The generation script now checks whether the file has changed before writing it to `/src` or `/include`. This is to improve compilation time when testing changes to generated code.

It works by creating a `/temp` directory, writing the generated code to `/temp/src` and `/temp/include`, then syncing those folders with `/src` and `/include` by deleting files  that no longer exist and copying files that have changed or been added since the last code generation. Finally the `/temp` directory is deleted

If `/src` and `/include` don't exist (i.e. it's the first time the generation script has been run), `/temp/src` will be copied to `/src` and `/temp/include` will be copied to `/include`.

.gitignore

@@ -6,6 +6,7 @@
 /lib/nodegit.js
 /node_modules/
 /src/
+/temp/
 /test/coverage/
 /test/home/
 /test/repos/

generate/scripts/generateMissingTests.js

@@ -12,7 +12,7 @@ module.exports = function generateMissingTests() {
       var testFilePath = path.join(testFilesPath, idef.filename + ".js");
       var result = {};
 
-      var file = utils.readFile(testFilePath);
+      var file = utils.readLocalFile(testFilePath);
       if (file) {
         var fieldsResult = [];
         var functionsResult = [];

generate/scripts/generateNativeCode.js

@@ -24,27 +24,27 @@ module.exports = function generateNativeCode() {
   };
 
   var partials = {
-    asyncFunction: utils.readFile("templates/partials/async_function.cc"),
-    callbackHelpers: utils.readFile("templates/partials/callback_helpers.cc"),
-    convertFromV8: utils.readFile("templates/partials/convert_from_v8.cc"),
-    convertToV8: utils.readFile("templates/partials/convert_to_v8.cc"),
-    doc: utils.readFile("templates/partials/doc.cc"),
-    fields: utils.readFile("templates/partials/fields.cc"),
-    guardArguments: utils.readFile("templates/partials/guard_arguments.cc"),
-    syncFunction: utils.readFile("templates/partials/sync_function.cc"),
-    fieldAccessors: utils.readFile("templates/partials/field_accessors.cc"),
-    traits: utils.readFile("templates/partials/traits.h")
+    asyncFunction: utils.readLocalFile("templates/partials/async_function.cc"),
+    callbackHelpers: utils.readLocalFile("templates/partials/callback_helpers.cc"),
+    convertFromV8: utils.readLocalFile("templates/partials/convert_from_v8.cc"),
+    convertToV8: utils.readLocalFile("templates/partials/convert_to_v8.cc"),
+    doc: utils.readLocalFile("templates/partials/doc.cc"),
+    fields: utils.readLocalFile("templates/partials/fields.cc"),
+    guardArguments: utils.readLocalFile("templates/partials/guard_arguments.cc"),
+    syncFunction: utils.readLocalFile("templates/partials/sync_function.cc"),
+    fieldAccessors: utils.readLocalFile("templates/partials/field_accessors.cc"),
+    traits: utils.readLocalFile("templates/partials/traits.h")
   };
 
   var templates = {
-    class_content: utils.readFile("templates/templates/class_content.cc"),
-    struct_content: utils.readFile("templates/templates/struct_content.cc"),
-    class_header: utils.readFile("templates/templates/class_header.h"),
-    struct_header: utils.readFile("templates/templates/struct_header.h"),
-    binding: utils.readFile("templates/templates/binding.gyp"),
-    nodegitCC: utils.readFile("templates/templates/nodegit.cc"),
-    nodegitJS: utils.readFile("templates/templates/nodegit.js"),
-    enums: utils.readFile("templates/templates/enums.js")
+    class_content: utils.readLocalFile("templates/templates/class_content.cc"),
+    struct_content: utils.readLocalFile("templates/templates/struct_content.cc"),
+    class_header: utils.readLocalFile("templates/templates/class_header.h"),
+    struct_header: utils.readLocalFile("templates/templates/struct_header.h"),
+    binding: utils.readLocalFile("templates/templates/binding.gyp"),
+    nodegitCC: utils.readLocalFile("templates/templates/nodegit.cc"),
+    nodegitJS: utils.readLocalFile("templates/templates/nodegit.js"),
+    enums: utils.readLocalFile("templates/templates/enums.js")
   };
 
   var filters = {
@@ -99,28 +99,32 @@ module.exports = function generateNativeCode() {
     return !idef.ignore;
   });
 
+  const tempDirPath = path.resolve(__dirname, "../../temp");
+  const tempSrcDirPath = path.join(tempDirPath, "src");
+  const tempIncludeDirPath = path.join(tempDirPath, "include");
 
-  fse.remove(path.resolve(__dirname, "../../src")).then(function() {
-    return fse.remove(path.resolve(__dirname, "../../include"));
-  }).then(function() {
-    return fse.copy(path.resolve(__dirname, "../templates/manual/include"), path.resolve(__dirname, "../../include"));
+  const finalSrcDirPath = path.join(__dirname, '../../src');
+  const finalIncludeDirPath = path.join(__dirname, '../../include');
+
+  fse.remove(tempDirPath).then(function() {
+    return fse.copy(path.resolve(__dirname, "../templates/manual/include"), tempIncludeDirPath);
   }).then(function() {
-    return fse.copy(path.resolve(__dirname, "../templates/manual/src"), path.resolve(__dirname, "../../src"));
+    return fse.copy(path.resolve(__dirname, "../templates/manual/src"), tempSrcDirPath);
   }).then(function() {
     // Write out single purpose templates.
     utils.writeFile("../binding.gyp", beautify(templates.binding.render(enabled)), "binding.gyp");
-    utils.writeFile("../src/nodegit.cc", templates.nodegitCC.render(enabled), "nodegit.cc");
+    utils.writeFile("../temp/src/nodegit.cc", templates.nodegitCC.render(enabled), "nodegit.cc");
     utils.writeFile("../lib/nodegit.js", beautify(templates.nodegitJS.render(enabled)), "nodegit.js");
     // Write out all the classes.
     enabled.forEach(function(idef) {
       if (idef.type && idef.type != "enum") {
         utils.writeFile(
-          "../src/" + idef.filename + ".cc",
+          "../temp/src/" + idef.filename + ".cc",
           templates[idef.type + "_content"].render(idef),
           idef.type + "_content.cc"
         );
         utils.writeFile(
-          "../include/" + idef.filename + ".h",
+          "../temp/include/" + idef.filename + ".h",
           templates[idef.type + "_header"].render(idef),
           idef.type + "_header.h"
         );
@@ -133,17 +137,24 @@ module.exports = function generateNativeCode() {
       if (astyle) {
         return exec(
           "astyle --options=\".astylerc\" "
-          + path.resolve(__dirname, "../../src") + "/*.cc "
-          + path.resolve(__dirname, "../../include") + "/*.h"
+          + tempSrcDirPath + "/*.cc "
+          + tempIncludeDirPath + "/*.h"
         ).then(function() {
           return exec(
             "rm "
-            + path.resolve(__dirname, "../../src") + "/*.cc.orig "
-            + path.resolve(__dirname, "../../include") + "/*.h.orig "
+            + tempSrcDirPath + "/*.cc.orig "
+            + tempIncludeDirPath + "/*.h.orig "
           );
         });
       }
     }, function() {})
+  }).then(function() {
+    return Promise.all([
+      utils.syncDirs(tempSrcDirPath, finalSrcDirPath),
+      utils.syncDirs(tempIncludeDirPath, finalIncludeDirPath),
+    ]);
+  }).then(function() {
+    return fse.remove(tempDirPath);
   }).catch(console.log);
 
 };

generate/scripts/utils.js

@@ -1,4 +1,5 @@
 const fse = require("fs-extra");
+const walk = require("walk");
 
 const fs = require("fs");
 const path = require("path");
@@ -10,7 +11,7 @@ var util = {
   pointerRegex: /\s*\*\s*/,
   doublePointerRegex: /\s*\*\*\s*/,
 
-  readFile: function(file) {
+  readLocalFile: function(file) {
     try {
       return fs.readFileSync(local(file)).toString();
     }
@@ -19,6 +20,15 @@ var util = {
     }
   },
 
+  readFile: function(filePath) {
+    try {
+      return fs.readFileSync(filePath).toString();
+    }
+    catch (unhandledException) {
+      return "";
+    }
+  },
+
   writeFile: function(file, content, header) {
     try {
       var file = local(file);
@@ -62,14 +72,84 @@ var util = {
     }).join("");
   },
 
+  getFilePathsRelativeToDir: function(dir) {
+    const files = [];
+    const walker = walk.walk(dir, { followLinks: false });
+    if (!util.isDirectory(dir)) {
+      return Promise.resolve([]);
+    }
+
+    return new Promise(function(resolve, reject) {
+      walker.on('file', function(root, stat, next) {
+        files.push(path.relative(dir, path.join(root, stat.name)));
+        next();
+      });
+
+      walker.on('end', function() {
+        resolve(files);
+      });
+
+      walker.on('errors', function() {
+        reject();
+      });
+    });
+  },
+
+  isFile: function(path) {
+    var isFile;
+    try {
+      isFile = fse.statSync(path).isFile();
+    } catch(e) {
+      isFile = false;
+    }
+
+    return isFile;
+  },
+
+  isDirectory: function(path) {
+    var isDirectory;
+    try {
+      isDirectory = fse.statSync(path).isDirectory();
+    } catch(e) {
+      isDirectory = false;
+    }
+
+    return isDirectory;
+  },
+
   isPointer: function(type) {
     return util.pointerRegex.test(type) || util.doublePointerRegex.test(type);
   },
 
   isDoublePointer: function(type) {
     return util.doublePointerRegex.test(type);
-  }
+  },
 
+  syncDirs: function(fromDir, toDir) {
+    return Promise.all([
+      util.getFilePathsRelativeToDir(toDir),
+      util.getFilePathsRelativeToDir(fromDir)
+    ]).then(function(filePaths) {
+      const toFilePaths = filePaths[0];
+      const fromFilePaths = filePaths[1];
+
+      // Delete files that aren't in fromDir
+      toFilePaths.forEach(function(filePath) {
+        if (!util.isFile(path.join(fromDir, filePath))) {
+          fse.remove(path.join(toDir, filePath));
+        }
+      });
+
+      // Copy files that don't exist in toDir or have different contents
+      fromFilePaths.forEach(function(filePath) {
+        const toFilePath = path.join(toDir, filePath);
+        const fromFilePath = path.join(fromDir, filePath);
+        if (!util.isFile(toFilePath) || util.readFile(toFilePath) !== util.readFile(fromFilePath)) {
+          fse.copy(fromFilePath, toFilePath);
+        }
+      });
+    });
+  }
 };
 
 module.exports = util;

package.json

@@ -52,7 +52,8 @@
     "js-beautify": "~1.5.10",
     "jshint": "~2.8.0",
     "lcov-result-merger": "~1.0.2",
-    "mocha": "~2.3.4"
+    "mocha": "~2.3.4",
+    "walk": "^2.3.9"
   },
   "vendorDependencies": {
     "libssh2": "1.6.0",