imprv: faster playlist handling and a few bugs fixed

src/sh/cache.sh

@@ -238,6 +238,18 @@ cache_get_file_batch() {
     awk -v dir="$CACHEDIR/$1/" -v f="/$fn" '{ print dir $0 f }'
 }
 
+# Detect missing cache files
+#
+# @argument $1: type
+# @argument $2: path to list with MusicBrainz IDs
+#
+# This method returns a nonzero value if some MusicBrainz objects listed in $2
+# are not cached.
+cached() {
+  cache_get_file_batch "$1" <"$2" |
+    xargs -d '\n' ls >/dev/null 2>&1 || return 1
+}
+
 # Print MusicBrainz ID associated to the file paths
 #
 # This reads from stdin any number of paths (one per line)
@@ -295,3 +307,41 @@ cache_rm_release() {
   info "Removing $d from cache"
   rm -rf "$d"
 }
+
+# Load missing cache entries (batch mode)
+#
+# argument $1: type
+#
+# This method reads one MusicBrainz IDs of the specified type from stdin (one
+# per line), and fetches the missing items.
+batch_load_missing() {
+  tmpf=$(mktemp)
+  cat |
+    cache_get_file_batch "$1" |
+    xargs -d '\n' \
+      sh -c 'for f; do [ -e "$f" ] || echo "$f"; done' _ |
+    cache_mbid_from_path_batch >"$tmpf"
+  lines=$(wc -l "$tmpf" | cut -d ' ' -f 1)
+  if [ "$lines" -gt 0 ]; then
+    case "$1" in
+    "$TYPE_ARTIST") tt="artists" ;;
+    "$TYPE_RELEASEGROUP") tt="release groups" ;;
+    "$TYPE_RELEASE") tt="releases" ;;
+    esac
+    info "Fetching missing $tt"
+    cnt=0
+    while IFS= read -r mbid; do
+      case "$1" in
+      "$TYPE_ARTIST")
+        name=$(mb_artist "$mbid" | $JQ '.name')
+        ;;
+      "$TYPE_RELEASEGROUP") name=$(mb_releasegroup "$mbid" | $JQ '.title') ;;
+      "$TYPE_RELEASE") name=$(mb_release "$mbid" | $JQ '.title') ;;
+      esac
+      cnt=$((cnt + 1))
+      info "$(printf "%d/%d (%s: %s)" "$cnt" "$lines" "$mbid" "$name")"
+      sleep 1
+    done <"$tmpf"
+  fi
+  rm -f "$tmpf"
+}