tools/pdf-comparison.sh: stop relying on /usr/bin/timeout

tools/pdf-comparison.sh

 #!/bin/sh
 
 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This tool compares the PDF output of Skia's DM tool of two commits.
 
 CONTROL_COMMIT="$1"
 EXPERIMENT_COMMIT="$2"
 
 SOURCE="${3:-gm}" # could be 'skp'
 
 if ! [ "$1" ] || ! [ "$2" ]; then
     echo "usage:" >&2
     echo "  $0 CONTROL_COMMIT EXPERIMENT_COMMIT [SOURCE]" >&2
     exit 1
 fi
 
 BAD=''
-for CMD in 'python' 'ninja' 'pdfium_test' 'timeout' 'skdiff'; do
+for CMD in 'python' 'ninja' 'pdfium_test' 'skdiff'; do
     if ! command -v "$CMD" > /dev/null ; then
         echo "could not find $CMD command in PATH." >&2
         BAD=1
     fi
 done
 if [ "$BAD" ]; then exit 1; fi
 
 cd "$(dirname "$0")/.."
 if [ "$(git diff --shortstat)" ]; then
     echo "please stash your changes" >&2
@@ skipping 29 matching lines @@
         echo "PDF differs: $(basename "$con")"
         DIFFS=1
     fi
 done
 if [ -z "$DIFFS" ]; then
     echo 'All PDFs are byte-identical!'
     rm -r "$DIR"
     exit 0;
 fi
 
+# Portable version of timeout from GNU coreutils.
+timeout_py() { python -c "$(cat <<EOF
+import sys, subprocess, threading
+proc = subprocess.Popen(sys.argv[2:])
+timer = threading.Timer(float(sys.argv[1]), proc.terminate)
+timer.start()
+proc.wait()
+timer.cancel()
+exit(proc.returncode)
+EOF
+)" "$@"; }
+
 # rasterize the remaining PDFs
 for pdf in "$CON_DIR"/*pdf "$EXP_DIR"/*pdf ; do
-    # timeout is from GNU coreutils
-    if timeout 10 pdfium_test --png "$pdf"; then
+    if timeout_py 10 pdfium_test --png "$pdf"; then
+        if ! [ -f "$pdf".*.png ] ; then
+            echo "Missing pdfium_test output: '$pdf.*.png'" >&2
+            exit 1
+        fi
         rm "$pdf"
     else
         echo "pdfium_test '$pdf' failed."
     fi
 done
 
 DIFFS=''
 # remove byte-identical PNGs:
 for con in "$CON_DIR"/*.png; do
     exp="$EXP_DIR/$(basename "$con")"
@@ skipping 13 matching lines @@
 # run remaining PNG files through skdiff:
 DIFF_DIR="${DIR}/skdiffout"
 skdiff "$CON_DIR" "$EXP_DIR"  "$DIFF_DIR"
 echo "'$DIFF_DIR/index.html'"
 
 if [ $(uname) = 'Darwin' ] ; then
     open "$DIFF_DIR/index.html"  # look at diffs
 elif [ $(uname) = 'Linux' ] ; then
     xdg-open "$DIFF_DIR/index.html"  # look at diffs
 fi