From 4410536f694d36014b9742a1c48ea11744434459 Mon Sep 17 00:00:00 2001
From: Florian Bruhin <git@the-compiler.org>
Date: Sat, 27 Sep 2014 22:56:50 +0200
Subject: [PATCH] Refactor :undo and save/restore history.

---
 qutebrowser/browser/commands.py      |  7 +++---
 qutebrowser/utils/qtutils.py         | 33 +++++++++++++++++++++++++++-
 qutebrowser/widgets/tabbedbrowser.py | 19 ++++++++++++----
 3 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/qutebrowser/browser/commands.py b/qutebrowser/browser/commands.py
index 5f27bc5fa..2b7b90ac5 100644
--- a/qutebrowser/browser/commands.py
+++ b/qutebrowser/browser/commands.py
@@ -511,10 +511,9 @@ class CommandDispatcher:
     @cmdutils.register(instance='command-dispatcher')
     def undo(self):
         """Re-open a closed tab (optionally skipping [count] closed tabs)."""
-        url_stack = objreg.get('url-stack', None)
-        if url_stack:
-            objreg.get('tabbed-browser').tabopen(url_stack.pop())
-        else:
+        try:
+            objreg.get('tabbed-browser').undo()
+        except IndexError:
             raise cmdexc.CommandError("Nothing to undo!")
 
     @cmdutils.register(instance='command-dispatcher')
diff --git a/qutebrowser/utils/qtutils.py b/qutebrowser/utils/qtutils.py
index a2a3c4b6a..7f59e7a9e 100644
--- a/qutebrowser/utils/qtutils.py
+++ b/qutebrowser/utils/qtutils.py
@@ -32,7 +32,8 @@ import sys
 import operator
 from distutils.version import StrictVersion as Version
 
-from PyQt5.QtCore import QEventLoop, qVersion
+from PyQt5.QtCore import (qVersion, QEventLoop, QDataStream, QByteArray,
+                          QIODevice)
 
 
 MAXVALS = {
@@ -128,6 +129,36 @@ def ensure_valid(obj):
         raise QtValueError(obj)
 
 
+def _check_qdatastream(stream):
+    """Check the status of a QDataStream and raise IOError if it's not ok."""
+    status_to_str = {
+        QDataStream.Ok: "The data stream is operating normally.",
+        QDataStream.ReadPastEnd: ("The data stream has read past the end of "
+                                  "the data in the underlying device."),
+        QDataStream.ReadCorruptData: "The data stream has read corrupt data.",
+        QDataStream.WriteFailed: ("The data stream cannot write to the "
+                                  "underlying device."),
+    }
+    if stream.status() != QDataStream.Ok:
+        raise IOError(status_to_str[stream.status()])
+
+
+def serialize(obj):
+    """Serialize an object into a QByteArray."""
+    data = QByteArray()
+    stream = QDataStream(data, QIODevice.WriteOnly)
+    stream << obj
+    _check_qdatastream(stream)
+    return data
+
+
+def deserialize(data, obj):
+    """Deserialize an object from a QByteArray."""
+    stream = QDataStream(data, QIODevice.ReadOnly)
+    stream >> obj
+    _check_qdatastream(stream)
+
+
 class QtValueError(ValueError):
 
     """Exception which gets raised by ensure_valid."""
diff --git a/qutebrowser/widgets/tabbedbrowser.py b/qutebrowser/widgets/tabbedbrowser.py
index 54dfb7c34..b969d3bf4 100644
--- a/qutebrowser/widgets/tabbedbrowser.py
+++ b/qutebrowser/widgets/tabbedbrowser.py
@@ -20,6 +20,7 @@
 """The main tabbed browser widget."""
 
 import functools
+import collections
 
 from PyQt5.QtWidgets import QSizePolicy
 from PyQt5.QtCore import pyqtSignal, pyqtSlot, QSize, QTimer, QUrl
@@ -34,6 +35,9 @@ from qutebrowser.browser import signalfilter, commands
 from qutebrowser.utils import log, message, usertypes, utils, qtutils, objreg
 
 
+UndoEntry = collections.namedtuple('UndoEntry', ['url', 'history'])
+
+
 class TabbedBrowser(tabwidget.TabWidget):
 
     """A TabWidget with QWebViews inside.
@@ -53,7 +57,7 @@ class TabbedBrowser(tabwidget.TabWidget):
         _tab_insert_idx_left: Where to insert a new tab with
                          tabbar -> new-tab-position set to 'left'.
         _tab_insert_idx_right: Same as above, for 'right'.
-        _url_stack: Stack of URLs of closed tabs.
+        _undo_stack: List of UndoEntry namedtuples of closed tabs.
 
     Signals:
         cur_progress: Progress of the current tab changed (loadProgress).
@@ -102,8 +106,7 @@ class TabbedBrowser(tabwidget.TabWidget):
         self.cur_load_started.connect(self.on_cur_load_started)
         self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
         self._tabs = []
-        self._url_stack = []
-        objreg.register('url-stack', self._url_stack)
+        self._undo_stack = []
         self._filter = signalfilter.SignalFilter(self)
         dispatcher = commands.CommandDispatcher()
         objreg.register('command-dispatcher', dispatcher)
@@ -244,12 +247,20 @@ class TabbedBrowser(tabwidget.TabWidget):
             objreg.delete('last-focused-tab')
         if not tab.cur_url.isEmpty():
             qtutils.ensure_valid(tab.cur_url)
-            self._url_stack.append(tab.cur_url)
+            history_data = qtutils.serialize(tab.history())
+            entry = UndoEntry(tab.cur_url, history_data)
+            self._undo_stack.append(entry)
         tab.shutdown()
         self._tabs.remove(tab)
         self.removeTab(idx)
         tab.deleteLater()
 
+    def undo(self):
+        """Undo removing of a tab."""
+        url, history_data = self._undo_stack.pop()
+        newtab = self.tabopen(url)
+        qtutils.deserialize(history_data, newtab.history())
+
     @pyqtSlot('QUrl', bool)
     def openurl(self, url, newtab):
         """Open a URL, used as a slot.