Cache compiled CoffeeScript on the Objective-C side.

This is a temporary fix, it just stores compiled scripts in memory. It
doesn't speed up the app start since the scripts need to be compiled
once. Here are some numbers.

#file load
pre: 1.5 seconds
post: 0.25 seconds

#spec load
pre: 5.4 seconds
post: 0.36 seconds

Atom/Classes/AtomApp.h

@@ -11,4 +11,7 @@
 - (void)performActionForMenuItem:(AtomMenuItem *)item;
 - (void)resetMainMenu;
 
+- (NSString *)getCachedScript:(NSString *)filePath;
+- (void)setCachedScript:(NSString *)filePath contents:(NSString *)contents;
+
 @end

Atom/Classes/AtomApp.m

@@ -9,6 +9,11 @@
 #define ATOM_USER_PATH ([[NSString stringWithString:@"~/.atom/"] stringByStandardizingPath])
 #define ATOM_STORAGE_PATH ([ATOM_USER_PATH stringByAppendingPathComponent:@".app-storage"])
 
+@interface AtomApp () {
+  NSMutableDictionary *_coffeeCache;
+}
+@end
+
 @implementation AtomApp
 
 @synthesize controllers = _controllers;
@@ -75,6 +80,8 @@
 }
 
 - (void)applicationDidFinishLaunching:(NSNotification *)notification {
+  _coffeeCache = [[NSMutableDictionary alloc] init];
+
   if ([[[NSProcessInfo  processInfo] environment] objectForKey:@"AUTO-TEST"]) {
     [self runSpecs:self];
   }
@@ -105,4 +112,33 @@
   [self resetMenu:self.mainMenu];
 }
 
+- (NSString *)getCachedScript:(NSString *)filePath {
+  NSDictionary *cachedObject = [_coffeeCache objectForKey:filePath];
+  if (!cachedObject) return nil;
+  
+  NSFileManager *fm = [NSFileManager defaultManager];
+  NSError *error = nil;
+  NSDictionary *attributes = [fm attributesOfItemAtPath:filePath error:&error];
+  if (error) {
+    NSLog(@"Error reading cached scripts: %@", [error localizedDescription]);
+    return nil;
+  }
+
+  NSDate *cachedAt = [cachedObject objectForKey:@"cachedAt"];
+  NSDate *modifedAt = [attributes objectForKey:NSFileModificationDate];
+  if (modifedAt && [modifedAt compare:cachedAt] == NSOrderedAscending) {
+    return [cachedObject objectForKey:@"script"];
+  }
+  else {
+    return nil;
+  }
+}
+
+- (void)setCachedScript:(NSString *)filePath contents:(NSString *)contents {
+  NSMutableDictionary *cachedObject = [NSMutableDictionary dictionary];
+  [cachedObject setObject:[NSDate date] forKey:@"cachedAt"];
+  [cachedObject setObject:contents forKey:@"script"];
+  [_coffeeCache setObject:cachedObject forKey:filePath];
+}
+
 @end

src/stdlib/require.coffee

@@ -58,8 +58,7 @@ exts =
     __jsc__.evalJSString_withScriptPath code, file
     __defines.pop()?.call()
   coffee: (file) ->
-    {CoffeeScript} = require 'coffee-script'
-    exts.js(file, CoffeeScript.compile(__read(file), filename: file))
+    exts.js(file, __coffeeCache(file))
 
 resolve = (file) ->
   if /!/.test file
@@ -110,6 +109,14 @@ __expand = (path) ->
 __exists = (path) ->
   OSX.NSFileManager.defaultManager.fileExistsAtPath path
 
+__coffeeCache = (filePath) ->
+  js = OSX.NSApp.getCachedScript(filePath)
+  if not js
+    {CoffeeScript} = require 'coffee-script'
+    js = CoffeeScript.compile(__read(filePath), filename: filePath)
+    OSX.NSApp.setCachedScript_contents(filePath, js)
+  js
+
 __read = (path) ->
   try
     OSX.NSString.stringWithContentsOfFile(path).toString()