Cache json files for cases where they're read repeatedly.

1 files changed, 18 insertions, 1 deletions

diff --git a/lib/utils/read-json.js b/lib/utils/read-json.js
index 8b71971b2..974123655 100644
--- a/lib/utils/read-json.js
+++ b/lib/utils/read-json.js
@@ -5,10 +5,17 @@ readJson.processJson = processJson
 var fs = require("./graceful-fs")
   , semver = require("./semver")
   , path = require("path")
-
+  , log = require("./log")
+  , cache = {}
+  , timers = {}
 function readJson (jsonFile, opts, cb) {
   if (typeof cb !== "function") cb = opts, opts = {}
+  if (cache.hasOwnProperty(jsonFile)) {
+    log.verbose(jsonFile, "from cache")
+    return cb(null, cache[jsonFile])
+  }
   fs.readFile(path.join(path.dirname(jsonFile), "wscript"), function (er, data) {
+    opts.file = jsonFile
     if (er) opts.wscript = false
     else opts.wscript = data.toString().match(/(^|\n)def build\b/)
                       && data.toString().match(/(^|\n)def configure\b/)
@@ -122,6 +129,16 @@ function processObject (opts, cb) { return function (er, json) {
   json._id = json.name+"-"+json.version
   json = testEngine(json)
   json = parsePeople(json)
+  if (opts.file) {
+    log.verbose(opts.file, "caching")
+    cache[opts.file] = json
+    // just in case this is a long-running process...
+    clearTimeout(timers[opts.file])
+    timers[opts.file] = setTimeout(function () {
+      delete cache[opts.file]
+      delete timers[opts.file]
+    }, 1000 * 60 * 60 * 24)
+  }
   if (cb) cb(null,json)
   return json
 }}