Enable maxStringLength config option

Matt Loring · Matt Loring · commit 4828beee6c53 · 2016-01-21T11:15:53.000-08:00
diff --git a/config.js b/config.js
@@ -58,12 +58,11 @@ module.exports = {
     // based on the length of names and values of the properties. This should
     // be somewhat proportional to the amount of processing needed to capture
     // the data and subsequently the network traffic.
-    maxDataSize: 20000
+    maxDataSize: 20000,
 
     // To limit the size of the buffer, we truncate long strings.
     // A value of 0 disables truncation.
-    // TODO: implement
-    //maxStringLength: 80
+    maxStringLength: 0
   },
 
 // These configuration options are for internal experimentation only.
diff --git a/lib/state.js b/lib/state.js
@@ -314,6 +314,10 @@ StateResolver.prototype.resolveVariable_ = function(name, value) {
   if (value.isPrimitive() || value.isRegExp()) {
     // primitives: undefined, null, boolean, number, string, symbol
     data.value = value.toText();
+    var maxLength = this.config_.capture.maxStringLength;
+    if (maxLength) {
+      data.value = data.value.substring(0, maxLength) + '...';
+    }
 
   } else if (value.isFunction()) {
     data.value = 'function ' + this.resolveFunctionName_(value) + '()';
diff --git a/test/test-v8debugapi.js b/test/test-v8debugapi.js
@@ -4,7 +4,7 @@
 /*4*/  return n+42;
 /*5*/}
 /*6*/function getterObject() {
-/*7*/  var hasGetter = { _a: 5, get a() { return this._a; } };
+/*7*/  var hasGetter = { _a: 5, get a() { return this._a; }, b: 'hello world' };
 /*8*/  return hasGetter.a;
 /*9*/}
 /**
@@ -372,6 +372,32 @@ describe('v8debugapi', function() {
       });
     });
 
+    it('should limit string length', function(done) {
+      var bp = {
+        id: 'fake-id-124',
+        location: { path: 'test-v8debugapi.js', line: 8 },
+        expressions: ['hasGetter']
+      };
+      var oldMax = config.capture.maxStringLength;
+      config.capture.maxStringLength = 3;
+      api.set(bp, function(err) {
+        assert.ifError(err);
+        api.wait(bp, function(err) {
+          assert.ifError(err);
+          var hasGetter = bp.evaluatedExpressions[0];
+          var getterVal = bp.variableTable[hasGetter.varTableIndex];
+          assert(getterVal.members.some(function(m) {
+            return m.value === 'hel...';
+          }));
+
+          api.clear(bp);
+          config.capture.maxStringLength = oldMax;
+          done();
+        });
+        process.nextTick(function() {getterObject();});
+      });
+    });
+
     it('should capture without values for invalid watch expressions', function(done) {
       // clone a clean breakpointInFoo
       var bp  = {
