From 44faac243210fd4ab72702a9acc2ff6cf7743d55 Mon Sep 17 00:00:00 2001
From: Nick Bowler <nbowler@draconx.ca>
Date: Sun, 25 Jul 2021 13:08:11 -0400
Subject: [PATCH] mpdthumb: Add support for embedded cover art.

MPD has recently gained the "readpicture" command in order to retrieve
cover images embedded in files.  This works very similarly to albumart.

We now have the necessary features in mpdexec to implement this in
mpdthumb.  When the --embedded option is supplied, the script will
first try readpicture, then albumart for each file specified.
---
 mpdthumb.sh | 58 ++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 12 deletions(-)

diff --git a/mpdthumb.sh b/mpdthumb.sh
index 4ff4249..4faf7a6 100755
--- a/mpdthumb.sh
+++ b/mpdthumb.sh
@@ -79,6 +79,9 @@ Options:
                     'auto', which queries the server to determine the
                     appropriate method.
   --no-binarylimit  Equivalent to --binarylimit=no
+  --embedded        Attempt to retrieve embedded covers using readpicture.
+                    This requires (and implies) --binarylimit.
+  --no-embedded     Use only album-level covers.  This is the default.
   --version         Print a version message and then exit.
   --help            Print this message and then exit.
 
@@ -87,6 +90,7 @@ EOF
 }
 
 opt_binarylimit=auto
+opt_embedded=no
 
 size=x128
 lastarg=
@@ -101,6 +105,8 @@ for arg; do
   --binarylimit=*) opt_binarylimit=${arg#--*=} ;;
   --no-binarylimit) opt_binarylimit=no ;;
   --binarylimit) opt_binarylimit=yes ;;
+  --embedded) opt_embedded=yes ;;
+  --no-embedded) opt_embedded=no ;;
   --size=*) size=${arg#--size=} ;;
   --small) size=56 ;;
   --size) lastarg=$arg ;;
@@ -133,6 +139,13 @@ tmp=`mktemp`
 exec 5>"$tmp" 6<"$tmp"
 rm -f "$tmp"
 
+# --embedded implies --binarylimit
+case $opt_embedded in
+yes) use_embedded=true ;;
+*) use_embedded=false ;;
+esac
+$use_embedded && opt_binarylimit=yes
+
 # Test for binarylimit command in MPD server.  We want to minimize data
 # transfer in order to make cache hits as fast as possible.
 #
@@ -158,34 +171,55 @@ else
   binarylimit_offset=2147483647
 fi
 
-for arg; do
-  arg=${arg%/*}/
-  shift; set x "$@" "$arg"; shift
+for file; do
+  case $file in
+  */*) dir=${file%/*}/ ;;
+  *) dir=/ ;;
+  esac
 
-  printf '%s\n' "$arg" | sed '/[ 	\\"'\'']/ {
+  if $use_embedded; then
+    shift; set x "$@" "$file" "$dir"; shift
+  else
+    file=
+  fi
+
+  printf '%s\n' "$dir" ${file:+"$file"} | sed -n '/[ 	\\"'\'']/ {
     s/[\\"]/\\&/g
     s/.*/"&"/
   }
-  s/.*/albumart & '"$binarylimit_offset"'/' >&3;
+  s/.*/albumart & '"$binarylimit_offset"'/
+  1h
+  2s/^albumart/readpicture/p
+  $ {
+    g
+    p
+  }' >&3;
 done
 
-<&4 $MPDEXEC --ignore-errors >&5 2>&1 || exit
+valid=
+<&4 $MPDEXEC --verbose --ignore-errors >&5 2>&1 || exit
 while read a b <&6; do
   case $a in
-  size:) :;;
+  readpicture|albumart)
+    prevn=$# file=$1 mode=$a; shift || exit; continue
+    ;;
+  size:)
+    valid=$mode$#
+    ;;
   ACK)
     case $b in
-    *binarylimit*) printf '%s: %s\n' "$argv0" "$a $b" 1>&2; exit 1 ;;
+    *'{binarylimit}'*|*'{readpicture}'*)
+      printf '%s: %s\n' "$argv0" "$a $b" 1>&2; exit 1 ;;
     esac
-
-    echo; shift || exit; continue ;;
+    test x"$valid" = x"readpicture$prevn" || echo
+    continue
+    ;;
   *) continue ;;
   esac
 
   # We combine the filename and the size to compute the cache key and
   # hope this suffices to detect stale entries.  Unfortunately MPD does
   # not currently give us the modified date which would be more useful...
-  file=$1; shift || exit
   cache_id=`printf 'MPD:%s:%s' "$file" "$b" | md5sum`
   cache_id=${cache_id:+${cache_id%% *}_$size.png}
 
@@ -199,7 +233,7 @@ EOF
     fi
 
     # Not cached, retrieve the entire image
-    $MPDEXEC --binary --download albumart "$file" >&3 || exit
+    $MPDEXEC --binary --download "$mode" "$file" >&3 || exit
     <&4 $CONVERT -scale "$size" - "$THUMBNAILDIR/tmp.$cache_id" ||
         { rc=$? rm -f "$THUMBNAILDIR/tmp.$cache_id"; exit $rc; }
     mv -f "$THUMBNAILDIR/tmp.$cache_id" "$THUMBNAILDIR/$cache_id"
-- 
2.43.0