Efficiently search for "all notes"

src/calibre/db/backend.py

@@ -1005,10 +1005,11 @@ class DB:
         return self.notes.unretire(self.conn, field, item_id, item_val)
 
     def notes_search(self,
-        fts_engine_query, use_stemming, highlight_start, highlight_end, snippet_size, restrict_to_fields, return_text, process_each_result
+        fts_engine_query, use_stemming, highlight_start, highlight_end, snippet_size, restrict_to_fields, return_text, process_each_result, limit
     ):
         yield from self.notes.search(
-            self.conn, fts_engine_query, use_stemming, highlight_start, highlight_end, snippet_size, restrict_to_fields, return_text, process_each_result)
+            self.conn, fts_engine_query, use_stemming, highlight_start, highlight_end, snippet_size, restrict_to_fields, return_text,
+            process_each_result, limit)
 
     def export_notes_data(self, outfile):
         import zipfile

src/calibre/db/cache.py

@@ -752,8 +752,9 @@ class Cache:
         return_text=True,
         result_type=tuple,
         process_each_result=None,
+        limit=None,
     ):
-        ' Search the text of notes using an FTS index '
+        ' Search the text of notes using an FTS index. If the query is empty return all notes. '
         return result_type(self.backend.notes_search(
             fts_engine_query,
             use_stemming=use_stemming,
@@ -763,6 +764,7 @@ class Cache:
             return_text=return_text,
             restrict_to_fields=restrict_to_fields,
             process_each_result=process_each_result,
+            limit=limit,
         ))
     # }}}
 

src/calibre/db/notes/connect.py

@@ -367,10 +367,37 @@ class Notes:
             with suppress(FileNotFoundError), open(path, 'rb') as f:
                 return {'name': name, 'data': f.read(), 'hash': resource_hash}
 
+    def all_notes(self, conn, restrict_to_fields=(), limit=None, snippet_size=64, return_text=True, process_each_result=None) -> list[dict]:
+        if snippet_size is None:
+            snippet_size = 64
+        char_size = snippet_size * 8
+        query = 'SELECT {0}.id, {0}.colname, {0}.item, substr({0}.searchable_text, 9, {1}) FROM {0} '.format('notes', char_size)
+        if restrict_to_fields:
+            query += ' WHERE notes_db.notes.colname IN ({})'.format(','.join(repeat('?', len(restrict_to_fields))))
+        query += ' ORDER BY ctime DESC'
+        if limit is not None:
+            query += f' LIMIT {limit}'
+        for record in conn.execute(query, tuple(restrict_to_fields)):
+            result = {
+                'id': record[0],
+                'field': record[1],
+                'item_id': record[2],
+                'text': record[3] if return_text else '',
+            }
+            if process_each_result is not None:
+                result = process_each_result(result)
+            ret = yield result
+            if ret is True:
+                break
+
     def search(self,
         conn, fts_engine_query, use_stemming, highlight_start, highlight_end, snippet_size, restrict_to_fields=(),
-        return_text=True, process_each_result=None
+        return_text=True, process_each_result=None, limit=None
     ):
+        if not fts_engine_query:
+            yield from self.all_notes(
+                conn, restrict_to_fields, limit=limit, snippet_size=snippet_size, return_text=return_text, process_each_result=process_each_result)
+            return
         fts_engine_query = unicode_normalize(fts_engine_query)
         fts_table = 'notes_fts' + ('_stemmed' if use_stemming else '')
         if return_text:
@@ -390,6 +417,8 @@ class Notes:
             query += ' notes_db.notes.colname IN ({}) AND '.format(','.join(repeat('?', len(restrict_to_fields))))
         query += f' "{fts_table}" MATCH ?'
         query += f' ORDER BY {fts_table}.rank '
+        if limit is not None:
+            query += f' LIMIT {limit}'
         try:
             for record in conn.execute(query, restrict_to_fields+(fts_engine_query,)):
                 result = {

src/calibre/db/tests/notes.py

@@ -171,6 +171,8 @@ def test_fts(self: 'NotesTest'):
     self.ae(ids_for_search('wunderbar'), {('authors', authors[0])})
     self.ae(ids_for_search('common'), {('authors', authors[0]), ('authors', authors[1]), ('tags', tags[0]), ('tags', tags[1])})
     self.ae(ids_for_search('common', ('tags',)), {('tags', tags[0]), ('tags', tags[1])})
+    self.ae(ids_for_search(''), ids_for_search('common'))
+    self.ae(ids_for_search('', ('tags',)), ids_for_search('common', ('tags',)))
 
     # test that searching by item value works
     an = cache.get_item_name('authors', authors[0])

src/calibre/gui2/library/notes.py

@@ -8,9 +8,11 @@ from qt.core import (
     QToolButton, QVBoxLayout, QWidget, pyqtSignal,
 )
 
+from calibre.db.backend import FTSQueryError
 from calibre.db.cache import Cache
-from calibre.gui2 import Application, gprefs
-from calibre.gui2.viewer.widgets import SearchBox
+from calibre.gui2 import Application, error_dialog, gprefs
+from calibre.gui2.viewer.widgets import ResultsDelegate, SearchBox
+from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import Dialog, FlowLayout
 
 
@@ -19,6 +21,27 @@ def current_db() -> Cache:
     return (getattr(current_db, 'ans', None) or get_gui().current_db).new_api
 
 
+class NotesResultsDelegate(ResultsDelegate):
+
+    add_ellipsis = False
+    emphasize_text = False
+
+    def result_data(self, result):
+        if not isinstance(result, dict):
+            return None, None, None, None, None
+        full_text = result['text']
+        parts = full_text.split('\x1d', 2)
+        before = after = ''
+        if len(parts) > 2:
+            before, text = parts[:2]
+            after = parts[2].replace('\x1d', '')
+        elif len(parts) == 2:
+            before, text = parts
+        else:
+            text = parts[0]
+        return False, before, text, after, False
+
+
 class RestrictFields(QWidget):
 
     def __init__(self, parent=None):
@@ -28,6 +51,7 @@ class RestrictFields(QWidget):
         self.restrict_label = QLabel(_('Restrict to:'))
         self.restricted_fields = []
         self.add_button = b = QToolButton(self)
+        b.setToolTip(_('Add categories to which to restrict results.\nWhen no categories are specified no restriction is in effect'))
         b.setIcon(QIcon.ic('plus.png')), b.setText(_('Add')), b.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonTextBesideIcon)
         b.setPopupMode(QToolButton.ToolButtonPopupMode.InstantPopup)
         self.fields_menu = m = QMenu()
@@ -128,8 +152,9 @@ class SearchInput(QWidget):
     @property
     def current_query(self):
         return {
-            'query': self.search_box.lineEdit().text().strip(),
+            'fts_engine_query': self.search_box.lineEdit().text().strip(),
             'restrict_to_fields': tuple(self.restrict.restricted_fields),
+            'use_stemming': bool(self.parent().use_stemmer.isChecked()),
         }
 
     def cleared(self):
@@ -144,6 +169,8 @@ class SearchInput(QWidget):
 
 class NotesBrowser(Dialog):
 
+    current_query = None
+
     def __init__(self, parent=None):
         super().__init__(_('Browse notes'), 'browse-notes-dialog', default_buttons=QDialogButtonBox.StandardButton.Close)
         self.setWindowIcon(QIcon.ic('notes.png'))
@@ -168,6 +195,26 @@ class NotesBrowser(Dialog):
         l.addLayout(h)
         h.addWidget(us), h.addStretch(10), h.addWidget(self.bb)
 
+    def do_find(self, backwards=False):
+        q = self.search_input.current_query
+        if q == self.current_query:
+            self.results_list.show_next(backwards)
+            return
+        try:
+            with BusyCursor():
+                results = current_db().search_notes(
+                    highlight_start='\x1d', highlight_end='\x1d', snippet_size=64, **q
+                )
+                self.results_list.set_results(results, bool(q['fts_engine_query']))
+                self.current_query = q
+        except FTSQueryError as err:
+            return error_dialog(self, _('Invalid search expression'), '<p>' + _(
+                'The search expression: {0} is invalid. The search syntax used is the'
+                ' SQLite Full text Search Query syntax, <a href="{1}">described here</a>.').format(
+                    err.query, 'https://www.sqlite.org/fts5.html#full_text_query_syntax'),
+                det_msg=str(err), show=True)
+
+
 
 
 if __name__ == '__main__':