Extend FileTypePlugin with postconvert() and postdelete() methods

src/calibre/customize/__init__.py

@@ -334,6 +334,16 @@ class FileTypePlugin(Plugin):  # {{{
     #: methods of the plugin are called.
     on_postimport  = False
 
+    #: If True, this plugin is run after a book file is added
+    #: to the database. In this case the postconvert method of
+    #: the plugin is called.
+    on_postconvert = False
+
+    #: If True, this plugin is run after a book file is deleted
+    #: from the database. In this case the postdelete method of
+    #: the plugin is called.
+    on_postdelete = False
+
     #: If True, this plugin is run just before a conversion
     on_preprocess  = False
 
@@ -378,6 +388,28 @@ class FileTypePlugin(Plugin):  # {{{
         '''
         pass  # Default implementation does nothing
 
+    def postconvert(self, book_id, book_format, db):
+        '''
+        Called post conversion, i.e., after the book file has been added to the database. It is
+        useful for modifying the book record based on the contents of the newly added file.
+
+        :param book_id: Database id of the added book.
+        :param book_format: The file type of the book that was added.
+        :param db: Library database.
+        '''
+        pass  # Default implementation does nothing
+
+    def postdelete(self, book_id, book_format, db):
+        '''
+        Called post deletion, i.e., after the book file has been deleted from the database. It is
+        useful for modifying the book record based on the format of the deleted file.
+
+        :param book_id: Database id of the added book.
+        :param book_format: The file type of the book that was added.
+        :param db: Library database.
+        '''
+        pass  # Default implementation does nothing
+
     def postadd(self, book_id, fmt_map, db):
         '''
         Called post add, i.e. after a book has been added to the db. Note that

src/calibre/customize/ui.py

@@ -122,15 +122,19 @@ def is_disabled(plugin):
 
 _on_import           = {}
 _on_postimport       = {}
+_on_postconvert      = {}
+_on_postdelete       = {}
 _on_preprocess       = {}
 _on_postprocess      = {}
 _on_postadd          = []
 
 
 def reread_filetype_plugins():
-    global _on_import, _on_postimport, _on_preprocess, _on_postprocess, _on_postadd
+    global _on_import, _on_postimport, _on_postconvert, _on_postdelete, _on_preprocess, _on_postprocess, _on_postadd
     _on_import           = defaultdict(list)
     _on_postimport       = defaultdict(list)
+    _on_postconvert      = defaultdict(list)
+    _on_postdelete       = defaultdict(list)
     _on_preprocess       = defaultdict(list)
     _on_postprocess      = defaultdict(list)
     _on_postadd          = []
@@ -146,6 +150,10 @@ def reread_filetype_plugins():
                 if plugin.on_postimport:
                     _on_postimport[ft].append(plugin)
                     _on_postadd.append(plugin)
+                if plugin.on_postconvert:
+                    _on_postconvert[ft].append(plugin)
+                if plugin.on_postdelete:
+                    _on_postdelete[ft].append(plugin)
                 if plugin.on_preprocess:
                     _on_preprocess[ft].append(plugin)
                 if plugin.on_postprocess:
@@ -155,6 +163,7 @@ def reread_filetype_plugins():
 def plugins_for_ft(ft, occasion):
     op = {
         'import':_on_import, 'preprocess':_on_preprocess, 'postprocess':_on_postprocess, 'postimport':_on_postimport,
+        'postconvert':_on_postconvert, 'postdelete':_on_postdelete,
     }[occasion]
     for p in chain(op.get(ft, ()), op.get('*', ())):
         if not is_disabled(p):
@@ -207,6 +216,34 @@ def run_plugins_on_postimport(db, book_id, fmt):
                 traceback.print_exc()
 
 
+def run_plugins_on_postconvert(db, book_id, fmt):
+    customization = config['plugin_customization']
+    fmt = fmt.lower()
+    for plugin in plugins_for_ft(fmt, 'postconvert'):
+        plugin.site_customization = customization.get(plugin.name, '')
+        with plugin:
+            try:
+                plugin.postconvert(book_id, fmt, db)
+            except:
+                print('Running file type plugin %s failed with traceback:'%
+                       plugin.name)
+                traceback.print_exc()
+
+
+def run_plugins_on_postdelete(db, book_id, fmt):
+    customization = config['plugin_customization']
+    fmt = fmt.lower()
+    for plugin in plugins_for_ft(fmt, 'postdelete'):
+        plugin.site_customization = customization.get(plugin.name, '')
+        with plugin:
+            try:
+                plugin.postdelete(book_id, fmt, db)
+            except:
+                print('Running file type plugin %s failed with traceback:'%
+                       plugin.name)
+                traceback.print_exc()
+
+
 def run_plugins_on_postadd(db, book_id, fmt_map):
     customization = config['plugin_customization']
     for plugin in _on_postadd:

src/calibre/db/cache.py

@@ -24,7 +24,7 @@ from time import monotonic, sleep, time
 from calibre import as_unicode, detect_ncpus, isbytestring
 from calibre.constants import iswindows, preferred_encoding
 from calibre.customize.ui import (
-    run_plugins_on_import, run_plugins_on_postadd, run_plugins_on_postimport,
+    run_plugins_on_import, run_plugins_on_postadd, run_plugins_on_postimport, run_plugins_on_postdelete,
 )
 from calibre.db import SPOOL_SIZE, _get_next_series_num_for_list
 from calibre.db.annotations import merge_annotations
@@ -1865,6 +1865,10 @@ class Cache:
 
         size_map = table.remove_formats(formats_map, self.backend)
         self.fields['size'].table.update_sizes(size_map)
+
+        for book_id, fmts in iteritems(formats_map):
+            run_plugins_on_postdelete(self, book_id, fmt)
+
         self._update_last_modified(tuple(formats_map))
         self.event_dispatcher(EventType.formats_removed, formats_map)
 

src/calibre/gui2/actions/convert.py

@@ -9,7 +9,7 @@ import os
 from functools import partial
 from qt.core import QModelIndex, QTimer
 
-from calibre.customize.ui import plugin_for_input_format
+from calibre.customize.ui import plugin_for_input_format, run_plugins_on_postconvert
 from calibre.gui2 import Dispatcher, error_dialog, gprefs
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.tools import convert_bulk_ebook, convert_single_ebook
@@ -274,6 +274,7 @@ class ConvertAction(InterfaceAction):
 
             with open(temp_files[-1].name, 'rb') as data:
                 db.add_format(book_id, fmt, data, index_is_id=True)
+            run_plugins_on_postconvert(db, book_id, fmt)
             self.gui.book_converted.emit(book_id, fmt)
             self.gui.status_bar.show_message(job.description + ' ' +
                     _('completed'), 2000)