Add a /display_corrections plugin.

doc/en/plugins/display_corrections.txt

@@ -0,0 +1,32 @@
+Display corrections
+===================
+
+Lists old versions of a corrected message.
+
+Installation
+------------
+
+============================
+
+ /load display\_corrections
+
+============================
+
+
+Usage
+-----
+This plugin adds a _/display\_corrections command that will display a list of
+old versions of a message.
+
+
+_/display\_corrections_ without argument will list the last corrected message,
+if any is found.  If an integer argument is given, /display\_corrections will
+go back gradually in the buffer to list the previous corrected messages, and so
+on.
+
+
+If you are scrolling in the buffer, poezio will list the corrected messages
+starting from the first you can see.  (although there are some problems with
+multiline messages).
+
+

doc/en/plugins/index.txt

@@ -70,6 +70,11 @@ Plugins index
     Logs the day change inside the buffers, to keep track of the days when
     backlogging.
 
+*Display corrections*:: link:display_corrections.html[Display corrections
+plugin]
+
+    Lists old versions of a corrected message.
+
 *Exec*:: link:exec.html[System command plugin]
 
     Runs a system command an optionally sends the output as a message.

plugins/display_corrections.py

@@ -0,0 +1,46 @@
+# A plugin that adds the /display_corrections command, to view the previous
+# versions of a corrected message.
+
+from plugin import BasePlugin
+from common import shell_split
+import tabs
+
+class Plugin(BasePlugin):
+    def init(self):
+        usage = 'Usage: /display_corrections <number>\nDisplay_corrections: display all the corrections of the number-th last corrected message.'
+        for tab_type in (tabs.MucTab, tabs.PrivateTab, tabs.ConversationTab):
+            self.add_tab_command(tab_type, 'display_corrections', self.command_display_corrections, usage)
+
+    def find_corrected(self, nb):
+        messages = self.core.get_conversation_messages()
+        if not messages:
+            return None
+        for message in messages[::-1]:
+            if message.old_message:
+                if nb == 1:
+                    return message
+                else:
+                    nb -= 1
+        return None
+
+    def command_display_corrections(self, args):
+        args = shell_split(args)
+        if len(args) == 1:
+            try:
+                nb = int(args[0])
+            except:
+                return self.core.command_help('display_corrections')
+        else:
+            nb = 1
+        message = self.find_corrected(nb)
+        if message:
+            display = []
+            while message:
+                display.append('%s %s%s%s %s' % (message.str_time, '* ' if message.me else '', message.nickname, '' if message.me else '>', message.txt))
+                message = message.old_message
+            self.core.information('Older versions:\n' + '\n'.join(display[::-1]), 'Info')
+        else:
+            self.core.information('No corrected message found.', 'Warning')
+
+    def cleanup(self):
+        del self.config