debugger: implement 'list'

lib/_debugger.js

@@ -277,6 +277,20 @@ Client.prototype.listbreakpoints = function(cb) {
   });
 };
 
+
+Client.prototype.reqSource = function(from, to, cb) {
+  var req = {
+    command: 'source',
+    fromLine: from,
+    toLine: to
+  };
+
+  this.req(req, function(res) {
+    if (cb) cb(res.body);
+  });
+};
+
+
 // client.next(1, cb);
 Client.prototype.step = function(action, count, cb) {
   var req = {
@@ -293,7 +307,7 @@ Client.prototype.step = function(action, count, cb) {
 
 
 var helpMessage = 'Commands: run, kill, print, step, next, ' +
-                  'continue, scripts, backtrace, version, quit';
+                  'continue, list, scripts, backtrace, version, quit';
 
 function SourceUnderline(sourceText, position) {
   if (!sourceText) return;
@@ -468,6 +482,31 @@ Interface.prototype.handleBreak = function(r) {
 };
 
 
+function intChars(n) {
+  // TODO dumb:
+  if (n < 50) {
+    return 2;
+  } else if (n < 950) {
+    return 3;
+  } else if (n < 9950) {
+    return 4;
+  } else {
+    return 5;
+  }
+}
+
+
+function leftPad(n) {
+  var s = n.toString();
+  var nchars = intChars(n);
+  var nspaces = nchars - s.length;
+  for (var i = 0; i < nspaces; i++) {
+    s = ' ' + s;
+  }
+  return s;
+}
+
+
 Interface.prototype.handleCommand = function(cmd) {
   var self = this;
 
@@ -522,6 +561,44 @@ Interface.prototype.handleCommand = function(cmd) {
       term.prompt();
     });
 
+
+  } else if ('l' == cmd || 'list' == cmd) {
+    if (!client) {
+      self.printNotConnected();
+      return;
+    }
+
+    var from = client.currentSourceLine - 5;
+    var to = client.currentSourceLine + 5;
+
+    client.reqSource(from, to, function(res) {
+      var lines = res.source.split('\n');
+      for (var i = 0; i < lines.length; i++) {
+        var lineno = res.fromLine + i + 1;
+        if (lineno < from || lineno > to) continue;
+
+        if (lineno == 1) {
+          // The first line needs to have the module wrapper filtered out of
+          // it.
+          var wrapper = require('module').wrapper[0];
+          lines[i] = lines[i].slice(wrapper.length);
+        }
+
+        if (lineno == 1 + client.currentSourceLine) {
+          var nchars = intChars(lineno);
+          var pointer = '';
+          for (var j = 0; j < nchars - 1; j++) {
+            pointer += '=';
+          }
+          pointer += '>';
+          console.log(pointer + ' ' + lines[i]);
+        } else {
+          console.log(leftPad(lineno) + ' ' + lines[i]);
+        }
+      }
+      term.prompt();
+    });
+
   } else if (/^backtrace/.test(cmd) || /^bt/.test(cmd)) {
     if (!client) {
       self.printNotConnected();