Rework local cover art handling

Local cover art as a provider doesn't make sense - local cover art is a
property of a file, same as tag cover art. Move the handling of local
cover art to the File class.

TODO: Need to resolve how to configure load ordering of tag cover art
vs local cover art. Also, there needs to be a config ui written.

In the current state, the local_cover_regex setting is re-used, and a
new load_local_cover_art boolean is used to enable the feature.

This will probably fix many of the causes of PICARD-1001.

Author: kepstin

picard/coverart/image.py

@@ -480,3 +480,6 @@ def __init__(self, filepath, types=None, comment='',
         super().__init__(url=url, types=types, comment=comment)
         self.support_types = support_types
         self.support_multi_types = support_multi_types
+        path = url.toLocalFile()
+        with open(path, 'rb') as file:
+            self.set_data(file.read())

picard/coverart/providers/__init__.py

@@ -35,7 +35,6 @@
 from picard.coverart.providers.caa_release_group import (
     CoverArtProviderCaaReleaseGroup,
 )
-from picard.coverart.providers.local import CoverArtProviderLocal
 from picard.coverart.providers.provider import (  # noqa: F401 # pylint: disable=unused-import
     CoverArtProvider,
     ProviderOptions,
@@ -92,7 +91,6 @@ def label(p):
 
 
 __providers = [
-    CoverArtProviderLocal,
     CoverArtProviderCaa,
     CoverArtProviderUrlRelationships,
     CoverArtProviderCaaReleaseGroup,

picard/coverart/providers/local.py

@@ -63,6 +63,11 @@
     IS_MACOS,
     IS_WIN,
 )
+from picard.coverart.image import (
+    CoverArtImageError,
+    LocalFileCoverArtImage
+)
+from picard.coverart.utils import CAA_TYPES
 from picard.metadata import (
     Metadata,
     SimMatchTrack,
@@ -240,6 +245,10 @@ def _loading_finished(self, callback, result=None, error=None):
             postprocessors = []
             if config.setting["guess_tracknumber_and_title"]:
                 postprocessors.append(self._guess_tracknumber_and_title)
+            # If no cover art was loaded from file tags, try loading from a local file
+            # TODO: should this be a preference? should we load from both sources?
+            if config.setting["load_local_cover_art"] and len(result.images) == 0:
+                self._load_local_cover_art(result, config)
             self._copy_loaded_metadata(result, postprocessors)
         # use cached fingerprint from file metadata
         if not config.setting["ignore_existing_acoustid_fingerprints"]:
@@ -250,6 +259,48 @@ def _loading_finished(self, callback, result=None, error=None):
         self.update()
         callback(self)
 
+    _types_split_re = re.compile('[^a-z0-9]', re.IGNORECASE)
+    _known_types = set([t['name'] for t in CAA_TYPES])
+    _default_types = ['front']
+
+    def get_types(self, string):
+        found = set([x.lower() for x in self._types_split_re.split(string) if x])
+        return list(found.intersection(self._known_types))
+
+    def _load_local_cover_art(self, metadata, config):
+        log.debug("Attempting to load cover art from local files")
+        match_re = re.compile(config.setting['local_cover_regex'], re.IGNORECASE)
+        current_dir = os.path.dirname(self.filename)
+        for root, dirs, files in os.walk(current_dir):
+            for filename in files:
+                m = match_re.search(filename)
+                if not m:
+                    continue
+                filepath = os.path.join(current_dir, root, filename)
+                if not os.path.exists(filepath):
+                    continue
+                try:
+                    type_from_filename = self.get_types(m.group(1))
+                except IndexError:
+                    type_from_filename = []
+                try:
+                    coverartimage = LocalFileCoverArtImage(
+                        filepath,
+                        types=type_from_filename or self._default_types,
+                        support_types=True,
+                        support_multi_types=True
+                    )
+
+                    log.debug("Loaded local cover art image: %r", coverartimage)
+                except OSError as exc:
+                    (errnum, errmsg) = exc.args
+                    log.error("Failed to read %r: %s (%d)" %
+                            (filepath, errmsg, errnum))
+                except (CoverArtImageError) as e:
+                    log.error('Cannot load image from %r: %s' % (filename, e))
+                else:
+                    metadata.images.append(coverartimage)
+
     def _copy_loaded_metadata(self, metadata, postprocessors=None):
         metadata['~length'] = format_time(metadata.length)
         if postprocessors: