From c631966bc0019614cdd6a2bcf08761cdf0e5ab3b Mon Sep 17 00:00:00 2001
From: Simon Lydell <simon.lydell@gmail.com>
Date: Fri, 13 May 2016 08:05:03 +0200
Subject: [PATCH] Fix frame scripts being loaded more than once sometimes

1. Open several tabs.
2. Set Firefox to remember your tabs between sessions.
3. Restart Firefox. All but the current tab will now be in a "pending"
   (unloaded) state.
4. Update/re-install VimFx.
5. Visit one of the pending tabs.

Now, the frame script will be loaded _twice_ in that tab, which for
example causes `f` to produce double-clicks. This is especially
noticeable during development, when you update/re-install VimFx all the
time.

The reason is that Firefox does not seem to load frame scripts in
pending tabs immediately. Instead, the URI to the frame script we asked
to load is remembered and then loaded when you actually visit the
pending tab in question. If you update VimFx before doing so, yet one
frame script URI will be pushed to that stack, causing _two_ instances
of it to be loaded when visiting the tab. Both of those will be from the
new VimFx version; the URIs are the same, and the file at that URI has
now been updated.

This commit attempts to solve this problem by generating a
`bootstrap-frame-$BUILD_TIME.js` file (which simply runs
`bootstrap.coffee`) and loading that as a frame script. This means that
old saved frame script URIs will point to non-existing files and thus
be harmless.
---
 extension/bootstrap-frame.js.tmpl |  5 +++++
 extension/bootstrap.coffee        |  2 +-
 extension/lib/main.coffee         |  8 +++++++-
 gulpfile.coffee                   | 16 +++++++++++++++-
 4 files changed, 28 insertions(+), 3 deletions(-)
 create mode 100644 extension/bootstrap-frame.js.tmpl

diff --git a/extension/bootstrap-frame.js.tmpl b/extension/bootstrap-frame.js.tmpl
new file mode 100644
index 0000000..8201ce0
--- /dev/null
+++ b/extension/bootstrap-frame.js.tmpl
@@ -0,0 +1,5 @@
+Services.scriptloader.loadSubScript(
+  Services.io.newURI('{{{ ADDON_PATH }}}/content/bootstrap.js', null, null).spec,
+  this,
+  'UTF-8'
+)
diff --git a/extension/bootstrap.coffee b/extension/bootstrap.coffee
index b19a6b7..c4c2747 100644
--- a/extension/bootstrap.coffee
+++ b/extension/bootstrap.coffee
@@ -31,7 +31,7 @@
 do (global = this) ->
 
   {classes: Cc, interfaces: Ci, utils: Cu} = Components
-  ADDON_PATH = 'chrome://vimfx'
+  ADDON_PATH = do -> # @echo ADDON_PATH
   IS_FRAME_SCRIPT = (typeof content != 'undefined')
   BUILD_TIME = do -> # @echo BUILD_TIME
   REQUIRE_DATA = do -> # @echo REQUIRE_DATA
diff --git a/extension/lib/main.coffee b/extension/lib/main.coffee
index 13de516..5744c40 100644
--- a/extension/lib/main.coffee
+++ b/extension/lib/main.coffee
@@ -123,7 +123,13 @@ module.exports = (data, reason) ->
     callback(true)
   )
 
-  messageManager.load("#{ADDON_PATH}/content/bootstrap.js")
+  # For tabs not visited yet since a session restore (“pending” tabs), Firefox
+  # seems to not load the frame script immediately, but instead remember the URI
+  # and load it when the user eventually visits that tab. If VimFx is updated
+  # during that time this means that the below URI is saved several times, and
+  # will be loaded that many times. Therefore the URI is changed with each
+  # build, causing remembered URIs to point to non-existent files.
+  messageManager.load("#{ADDON_PATH}/content/bootstrap-frame-#{BUILD_TIME}.js")
 
   # @if TESTS
   test(vimfx)
diff --git a/gulpfile.coffee b/gulpfile.coffee
index 3f70832..89c7e91 100644
--- a/gulpfile.coffee
+++ b/gulpfile.coffee
@@ -45,6 +45,9 @@ TEST = 'extension/test'
 BASE_LOCALE = 'en-US'
 UPDATE_ALL = /\s*UPDATE_ALL$/
 
+ADDON_PATH = 'chrome://vimfx'
+BUILD_TIME = Date.now()
+
 argv = process.argv.slice(2)
 
 {join} = path
@@ -79,7 +82,8 @@ gulp.task('coffee', ->
   ].concat(if test then 'extension/test/**/*.coffee' else []),
   {base: 'extension'})
     .pipe(preprocess({context: {
-      BUILD_TIME: Date.now()
+      BUILD_TIME
+      ADDON_PATH: JSON.stringify(ADDON_PATH)
       REQUIRE_DATA: JSON.stringify(precompute('.'), null, 2)
       TESTS:
         if test
@@ -94,6 +98,15 @@ gulp.task('coffee', ->
     .pipe(gulp.dest(DEST))
 )
 
+gulp.task('bootstrap-frame.js', ->
+  gulp.src('extension/bootstrap-frame.js.tmpl')
+    .pipe(mustache({ADDON_PATH}))
+    .pipe(tap((file) ->
+      file.path = file.path.replace(/\.js\.tmpl$/, "-#{BUILD_TIME}.js")
+    ))
+    .pipe(gulp.dest(DEST))
+)
+
 gulp.task('chrome.manifest', ->
   gulp.src('extension/chrome.manifest.tmpl')
     .pipe(template({locales: fs.readdirSync(LOCALE).map((locale) -> {locale})}))
@@ -125,6 +138,7 @@ gulp.task('install.rdf', ->
 )
 
 gulp.task('templates', [
+  'bootstrap-frame.js'
   'chrome.manifest'
   'install.rdf'
 ])
-- 
2.39.3