1 files changed, 51 insertions, 0 deletions
diff --git a/deps/npm/lib/utils/sha.js b/deps/npm/lib/utils/sha.js
new file mode 100644
index 0000000000..17b8c38f9c
--- /dev/null
+++ b/deps/npm/lib/utils/sha.js
@@ -0,0 +1,51 @@
+
+var fs = require("graceful-fs")
+  , crypto = require("crypto")
+  , log = require("./log.js")
+  , binding
+
+try { binding = process.binding("crypto") }
+catch (e) { binding = null }
+
+exports.check = check
+exports.get = get
+
+function check (file, sum, cb) {
+  if (!binding) {
+    log.warn("crypto binding not found. Cannot verify shasum.", "shasum")
+    return cb()
+  }
+  get(file, function (er, actual) {
+    if (er) return log.er(cb, "Error getting shasum")(er)
+    var expected = sum.toLowerCase().trim()
+      , ok = actual === expected
+    cb(ok ? null : new Error(
+      "shasum check failed for "+file+"\n"
+      +"Expected: "+expected+"\n"
+      +"Actual:   "+actual))
+  })
+}
+
+function get (file, cb) {
+  if (!binding) {
+    log.warn("crypto binding not found. Cannot verify shasum.", "shasum")
+    return cb()
+  }
+  var h = crypto.createHash("sha1")
+    , s = fs.createReadStream(file)
+    , errState = null
+  s.on("error", function (er) {
+    if (errState) return
+    log.silly(er.stack || er.message, "sha error")
+    return cb(errState = er)
+  }).on("data", function (chunk) {
+    if (errState) return
+    log.silly(chunk.length, "updated sha bytes")
+    h.update(chunk)
+  }).on("end", function () {
+    if (errState) return
+    var actual = h.digest("hex").toLowerCase().trim()
+    log(actual+"\n"+file, "shasum")
+    cb(null, actual)
+  })
+}