Clean up DjVuImage::retrieveMetaData including shellbox support

Following up Id9539a28f0f143539334002c3:

* Don't run the script twice.
* Wrap the decoded dump in an array with key "data".
* The default assignment for DJVU_DUMP and DJVU_TXT had the effect of
  running the scripts anyway if the configuration variables are null.
  Don't do that.
* If both $wgDjvuDump and $wgDjvuTxt are null, don't run the shellbox
  script.
* Centralise shell location configuration.
* Factor out call to convertDumpToJSON().
* Instead of txt_exit_code, just use existence of the file to
  communicate success. This avoids a deprecation warning if
  txt_exit_code was not received, due to passing null to trim.
* Check for the existence of the result files instead of just trying to
  use them.
* Check the exit status of the overall script.
* Confirm that the BoxedCommand branch is functional and works in CLI
  mode by using it in DjvuTest.
* Change the service name from "media" to "djvu". Existing examples are
  "pagedtiffhandler" and "pdfhandler", i.e. named after the extension,
  there is no other core caller. I think it should be more fine-grained
  than "media". The name was possibly a conflation with the
  ProductionServices array key.

Also:

* Check the exit status of djvudump and don't use the output file if it
  is non-zero.
* Check the return value of convertDumpToJSON().
* Don't use isset() unless error suppression is intended.

Bug: T352515
Change-Id: If41a2baada2e4e2462518c1f437af458feb29632

1 files changed, 19 insertions, 10 deletions

diff --git a/includes/media/scripts/retrieveDjvuMetaData.sh b/includes/media/scripts/retrieveDjvuMetaData.sh
index 601b20a97d4c..5ca0fb6a33aa 100644
--- a/includes/media/scripts/retrieveDjvuMetaData.sh
+++ b/includes/media/scripts/retrieveDjvuMetaData.sh
@@ -1,23 +1,32 @@
 #!/bin/sh
-# Get parameters from environment
-export DJVU_DUMP="${DJVU_DUMP:-djvudump}"
-export DJVU_TXT="${DJVU_TXT:-djvutxt}"
+
 runDump() {
+	local ret
 	# djvudump is faster than djvutoxml (now abandoned) as of version 3.5
 	# https://sourceforge.net/p/djvu/bugs/71/
 	"$DJVU_DUMP" file.djvu > dump
+	ret="$?"
+	if [ "$ret" -ne 0 ]; then
+		echo "djvudump failed with exit code $ret" 1>&2
+		rm -f dump
+	fi
 }
 runTxt() {
+	local ret
 	# Text layer
-	"$DJVU_TXT" \
-		--detail=page \
-		file.djvu > txt
-	# Store exit code so we can use it later
-	echo $? > txt_exit_code
+	if ! "$DJVU_TXT" --detail=page file.djvu > txt; then
+		rm -f txt
+	fi
+	ret="$?"
+	if [ "$ret" -ne 0 ]; then
+		echo "djvutxt failed with exit code $ret" 1>&2
+		rm -f txt
+	fi
 }
-if [ -x "$DJVU_DUMP" ]; then
+if [ -n "$DJVU_DUMP" ]; then
 	runDump
 fi
-if [ -x "$DJVU_TXT" ]; then
+if [ -n "$DJVU_TXT" ]; then
 	runTxt
 fi
+exit 0