From 9af485a584e47fd503ed5c62b9f6482574715f1e Mon Sep 17 00:00:00 2001
From: Florian Dold <florian.dold@gmail.com>
Date: Mon, 10 Oct 2016 03:50:11 +0200
Subject: Squashed 'thirdparty/systemjs/' content from commit 5ed69b6

git-subtree-dir: thirdparty/systemjs
git-subtree-split: 5ed69b6344e8fc1cd43bf758350b2236f57e1499
---
 lib/depCache.js | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 lib/depCache.js

(limited to 'lib/depCache.js')

diff --git a/lib/depCache.js b/lib/depCache.js
new file mode 100644
index 000000000..ced47a0e3
--- /dev/null
+++ b/lib/depCache.js
@@ -0,0 +1,44 @@
+/*
+ * Dependency Tree Cache
+ * 
+ * Allows a build to pre-populate a dependency trace tree on the loader of 
+ * the expected dependency tree, to be loaded upfront when requesting the
+ * module, avoinding the n round trips latency of module loading, where 
+ * n is the dependency tree depth.
+ *
+ * eg:
+ * SystemJS.depCache = {
+ *  'app': ['normalized', 'deps'],
+ *  'normalized': ['another'],
+ *  'deps': ['tree']
+ * };
+ * 
+ * SystemJS.import('app') 
+ * // simultaneously starts loading all of:
+ * // 'normalized', 'deps', 'another', 'tree'
+ * // before "app" source is even loaded
+ *
+ */
+
+(function() {
+  hookConstructor(function(constructor) {
+    return function() {
+      constructor.call(this);
+      this.depCache = {};
+    }
+  });
+
+  hook('locate', function(locate) {
+    return function(load) {
+      var loader = this;
+      // load direct deps, in turn will pick up their trace trees
+      var deps = loader.depCache[load.name];
+      if (deps)
+        for (var i = 0; i < deps.length; i++)
+          loader['import'](deps[i], load.name);
+
+      return locate.call(loader, load);
+    };
+  });
+})();
+  
-- 
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