From 164c79ce0c54f433e5659aa322d5e87cea0f8085 Mon Sep 17 00:00:00 2001
From: Nick Fitzgerald <fitzgen@gmail.com>
Date: Tue, 18 Feb 2014 14:35:50 -0800
Subject: [PATCH] Bug 974072 - Only restore breakpoints if there are
 breakpoints in the debugger server's breakpoint store; r=past

---
 toolkit/devtools/server/actors/script.js | 38 +++++++++++++++++-------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/toolkit/devtools/server/actors/script.js b/toolkit/devtools/server/actors/script.js
index 306c0a5e38a..aa431a62f7e 100644
--- a/toolkit/devtools/server/actors/script.js
+++ b/toolkit/devtools/server/actors/script.js
@@ -20,6 +20,8 @@ let OBJECT_PREVIEW_MAX_ITEMS = 10;
  * as after a refresh).
  */
 function BreakpointStore() {
+  this._size = 0;
+
   // If we have a whole-line breakpoint set at LINE in URL, then
   //
   //   this._wholeLineBreakpoints[URL][LINE]
@@ -44,6 +46,8 @@ function BreakpointStore() {
 }
 
 BreakpointStore.prototype = {
+  _size: null,
+  get size() { return this._size; },
 
   /**
    * Add a breakpoint to the breakpoint store.
@@ -75,6 +79,8 @@ BreakpointStore.prototype = {
       }
       this._wholeLineBreakpoints[url][line] = aBreakpoint;
     }
+
+    this._size++;
   },
 
   /**
@@ -91,23 +97,29 @@ BreakpointStore.prototype = {
     if (column != null) {
       if (this._breakpoints[url]) {
         if (this._breakpoints[url][line]) {
-          delete this._breakpoints[url][line][column];
+          if (this._breakpoints[url][line][column]) {
+            delete this._breakpoints[url][line][column];
+            this._size--;
 
-          // If this was the last breakpoint on this line, delete the line from
-          // `this._breakpoints[url]` as well. Otherwise `_iterLines` will yield
-          // this line even though we no longer have breakpoints on
-          // it. Furthermore, we use Object.keys() instead of just checking
-          // `this._breakpoints[url].length` directly, because deleting
-          // properties from sparse arrays doesn't update the `length` property
-          // like adding them does.
-          if (Object.keys(this._breakpoints[url][line]).length === 0) {
-            delete this._breakpoints[url][line];
+            // If this was the last breakpoint on this line, delete the line from
+            // `this._breakpoints[url]` as well. Otherwise `_iterLines` will yield
+            // this line even though we no longer have breakpoints on
+            // it. Furthermore, we use Object.keys() instead of just checking
+            // `this._breakpoints[url].length` directly, because deleting
+            // properties from sparse arrays doesn't update the `length` property
+            // like adding them does.
+            if (Object.keys(this._breakpoints[url][line]).length === 0) {
+              delete this._breakpoints[url][line];
+            }
           }
         }
       }
     } else {
       if (this._wholeLineBreakpoints[url]) {
-        delete this._wholeLineBreakpoints[url][line];
+        if (this._wholeLineBreakpoints[url][line]) {
+          delete this._wholeLineBreakpoints[url][line];
+          this._size--;
+        }
       }
     }
   },
@@ -2220,6 +2232,10 @@ ThreadActor.prototype = {
    * Restore any pre-existing breakpoints to the scripts that we have access to.
    */
   _restoreBreakpoints: function () {
+    if (this.breakpointStore.size === 0) {
+      return;
+    }
+
     for (let s of this.dbg.findScripts()) {
       this._addScript(s);
     }