process: Add internal _rawDebug() method

This is useful when we need to push some debugging messages out to
stderr, without going through the Writable class, or triggering any kind
of nextTick or callback behavior.

diff --git a/src/node.cc b/src/node.cc
index c26c1d2..3f49ec4 100644 (file)
--- a/src/node.cc
+++ b/src/node.cc
@@ -2525,6 +2525,22 @@ static void SignalExit(int signal) {
 }
 
 
+// Most of the time, it's best to use `console.error` to write
+// to the process.stderr stream.  However, in some cases, such as
+// when debugging the stream.Writable class or the process.nextTick
+// function, it is useful to bypass JavaScript entirely.
+static void RawDebug(const FunctionCallbackInfo<Value>& args) {
+  HandleScope scope(node_isolate);
+
+  assert(args.Length() == 1 && args[0]->IsString() &&
+         "must be called with a single string");
+
+  String::Utf8Value message(args[0]);
+  fprintf(stderr, "%s\n", *message);
+  fflush(stderr);
+}
+
+
 void Load(Handle<Object> process_l) {
   HandleScope handle_scope(node_isolate);
 
@@ -2581,6 +2597,8 @@ void Load(Handle<Object> process_l) {
   // thrown during process startup.
   try_catch.SetVerbose(true);
 
+  NODE_SET_METHOD(process_l, "_rawDebug", RawDebug);
+
   Local<Value> arg = process_l;
   f->Call(global, 1, &arg);
 }

diff --git a/src/node.js b/src/node.js
index 2df4ebb..3c7ede8 100644 (file)
--- a/src/node.js
+++ b/src/node.js
@@ -55,6 +55,8 @@
 
     startup.processChannel();
 
+    startup.processRawDebug();
+
     startup.resolveArgv0();
 
     // There are various modes that Node can run in. The most common two
@@ -649,7 +651,17 @@
       cp._forkChild(fd);
       assert(process.send);
     }
-  }
+  };
+
+
+  startup.processRawDebug = function() {
+    var format = NativeModule.require('util').format;
+    var rawDebug = process._rawDebug;
+    process._rawDebug = function() {
+      rawDebug(format.apply(null, arguments));
+    };
+  };
+
 
   startup.resolveArgv0 = function() {
     var cwd = process.cwd();

diff --git a/test/simple/test-process-raw-debug.js b/test/simple/test-process-raw-debug.js
new file mode 100644 (file)
index 0000000..260725d
--- /dev/null
+++ b/test/simple/test-process-raw-debug.js
@@ -0,0 +1,70 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+
+switch (process.argv[2]) {
+  case 'child':
+    return child();
+  case undefined:
+    return parent();
+  default:
+    throw new Error('wtf? ' + process.argv[2]);
+}
+
+function parent() {
+  var spawn = require('child_process').spawn;
+  var child = spawn(process.execPath, [__filename, 'child']);
+
+  var output = '';
+
+  child.stderr.on('data', function(c) {
+    output += c;
+  });
+
+  child.stderr.setEncoding('utf8');
+
+  child.stderr.on('end', function() {
+    assert.equal(output, 'I can still debug!\n');
+    console.log('ok - got expected message');
+  });
+
+  child.on('exit', function(c) {
+    assert(!c);
+    console.log('ok - child exited nicely');
+  });
+}
+
+function child() {
+  // even when all hope is lost...
+
+  process.nextTick = function() {
+    throw new Error('No ticking!');
+  };
+
+  var stderr = process.stderr;
+  stderr.write = function() {
+    throw new Error('No writing to stderr!');
+  };
+
+  process._rawDebug('I can still %s!', 'debug');
+}