From a9a05c5d6c8987d9192b9f7f755d8f48db709eaf Mon Sep 17 00:00:00 2001
From: isaacs <i@izs.me>
Date: Wed, 25 Aug 2010 02:58:05 -0700
Subject: Rework how exec works, and add pipe/spawn

---
 lib/utils/exec.js | 56 ++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 43 insertions(+), 13 deletions(-)

diff --git a/lib/utils/exec.js b/lib/utils/exec.js
index 5ef070950..5bdc512f2 100644
--- a/lib/utils/exec.js
+++ b/lib/utils/exec.js
@@ -1,22 +1,19 @@
 
+module.exports = exec
+exec.spawn = spawn
+exec.pipe = pipe
+
 var log = require("../utils/log")
+  , child_process = require("child_process")
+  , sys = require("sys")
 
-module.exports = function exec (cmd, args, env, pipe, cb) {
-  if (!cb) cb = pipe, pipe = false
+function exec (cmd, args, env, takeOver, cb) {
+  if (!cb) cb = takeOver, takeOver = true
   if (!cb) cb = env, env = process.env
   log.verbose(cmd+" "+args.map(JSON.stringify).join(" "), "exec")
-  var stdio = process.binding("stdio")
-    , fds = [ stdio.stdinFD || 0
-            , stdio.stdoutFD || 1
-            , stdio.stderrFD || 2
-            ]
-    , cp = require("child_process").spawn( cmd
-                                         , args
-                                         , env
-                                         , pipe ? null : fds
-                                         )
-    , stdout = ""
+  var stdout = ""
     , stderr = ""
+    , cp = spawn(cmd, args, env, takeOver)
   cp.stdout && cp.stdout.on("data", function (chunk) {
     if (chunk) stdout += chunk
   })
@@ -29,3 +26,36 @@ module.exports = function exec (cmd, args, env, pipe, cb) {
   })
   return cp
 }
+
+function logger (d) { if (d) process.binding("stdio").writeError(d+"") }
+function pipe (cp1, cp2, cb) {
+  sys.pump(cp1.stdout, cp2.stdin)
+  if (log.level <= log.LEVEL.silly) {
+    cp1.stderr.on("data", logger)
+    cp2.stderr.on("data", logger)
+  }
+  cp1.on("exit", function (code) {
+    if (!code) return log.verbose(cp2.name || "<unknown>", "success")
+    cp2.kill()
+    cb(new Error( "Failed "+(cp1.name || "<unknown>")+"\nexited with "+code))
+  })
+  cp2.on("exit", function (code) {
+    if (!code) return log.verbose(cp1.name || "<unknown>", "success", cb)
+    cb(new Error( "Failed "+(cp2.name || "<unknown>")+"\nexited with "+code))
+  })
+}
+
+function spawn (c, a, env, takeOver) {
+  var stdio = process.binding("stdio")
+    , fds = [ stdio.stdinFD || 0
+            , stdio.stdoutFD || 1
+            , stdio.stderrFD || 2
+            ]
+    , cp = child_process.spawn( c
+                              , a
+                              , env
+                              , takeOver ? fds : null
+                              )
+  cp.name = c +" "+ a.map(JSON.stringify).join(" ")
+  return cp
+}
-- 
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