Add --cov code coverage option

lib/module.js

@@ -347,6 +347,22 @@ Module.prototype._compile = function(content, filename) {
   // remove shebang
   content = content.replace(/^\#\!.*/, '');
 
+  // add coverage
+  if (process.cov) {
+    var lines = content.split('\n');
+
+    if (lines.length > 0) {
+      lines[0] = '__cov[__filename] = { 0: true}; ' + lines[0];
+    }
+
+    for (var i = 0; i < lines.length; i++) {
+      lines[i] =
+        lines[i].replace(/;$/, '; __cov[__filename][' + i + '] = true;');
+    }
+
+    content = lines.join('\n');
+  }
+
   function require(path) {
     return Module._load(path, self);
   }

src/node.cc

@@ -107,6 +107,7 @@ static char *eval_string = NULL;
 static int option_end_index = 0;
 static bool use_debug_agent = false;
 static bool debug_wait_connect = false;
+static bool cov = false;
 static int debug_port=5858;
 static int max_stack_size = 0;
 
@@ -2029,6 +2030,7 @@ Handle<Object> SetupProcessObject(int argc, char *argv[]) {
   process->Set(String::NewSymbol("ENV"), ENV);
 
   process->Set(String::NewSymbol("pid"), Integer::New(getpid()));
+  process->Set(String::NewSymbol("cov"), cov ? True() : False());
 
   // -e, --eval
   if (eval_string) {
@@ -2171,6 +2173,7 @@ static void PrintHelp() {
          "  --v8-options         print v8 command line options\n"
          "  --vars               print various compiled-in variables\n"
          "  --max-stack-size=val set max v8 stack size (bytes)\n"
+         "  --cov                code coverage; writes node-cov.json \n"
          "\n"
          "Enviromental variables:\n"
          "NODE_PATH              ':'-separated list of directories\n"
@@ -2193,6 +2196,9 @@ static void ParseArgs(int argc, char **argv) {
     if (strstr(arg, "--debug") == arg) {
       ParseDebugOpt(arg);
       argv[i] = const_cast<char*>("");
+    } else if (!strcmp(arg, "--cov")) {
+      cov = true;
+      argv[i] = const_cast<char*>("");
     } else if (strcmp(arg, "--version") == 0 || strcmp(arg, "-v") == 0) {
       printf("%s\n", NODE_VERSION);
       exit(0);

src/node.js

@@ -111,6 +111,9 @@
     global.GLOBAL = global;
     global.root = global;
     global.Buffer = NativeModule.require('buffer').Buffer;
+    if (process.cov) {
+      global.__cov = {};
+    }
   };
 
   startup.globalTimeouts = function() {
@@ -343,6 +346,20 @@
       var path = NativeModule.require('path');
       process.argv[0] = path.join(cwd, process.argv[0]);
     }
+
+    if (process.cov) {
+      process.on('exit', function() {
+        var coverage = JSON.stringify(__cov);
+        var path = NativeModule.require('path');
+        var fs = NativeModule.require('fs');
+        var filename = path.join(cwd, 'node-cov.json');
+        try {
+          fs.unlinkSync(filename);
+        } catch(e) {
+        }
+        fs.writeFileSync(filename, coverage);
+      });
+    }
   };
 
   // Below you find a minimal module system, which is used to load the node

test/common.js

@@ -64,6 +64,10 @@ process.on('exit', function() {
     knownGlobals.push(gc);
   }
 
+  if (global.__cov) {
+    knownGlobals.push(__cov);
+  }
+
   if (global.DTRACE_HTTP_SERVER_RESPONSE) {
     knownGlobals.push(DTRACE_HTTP_SERVER_RESPONSE);
     knownGlobals.push(DTRACE_HTTP_SERVER_REQUEST);