cli.ocrodjvu: ensure that exit code is non-zero if the program recove…

…red from an error.

doc/changelog

@@ -4,8 +4,10 @@ ocrodjvu (0.8) UNRELEASED; urgency=low
   * Add the “tesseract: ” prefix to messages Tesseract prints on stderr.
     https://bitbucket.org/jwilk/ocrodjvu/issue/10
     Thanks to Janusz S. Bień for the bug report.
+  * Ensure that exit code is non-zero if the program recovered from an error.
+    https://bitbucket.org/jwilk/ocrodjvu/issue/6
 
- -- Jakub Wilk <jwilk@jwilk.net>  Fri, 05 Jun 2015 22:05:09 +0200
+ -- Jakub Wilk <jwilk@jwilk.net>  Fri, 05 Jun 2015 23:14:11 +0200
 
 ocrodjvu (0.7.19) unstable; urgency=low
 

doc/ocrodjvu.xml

@@ -491,6 +491,27 @@
     </refsection>
 </refsection>
 
+<refsection>
+    <title>Exit status</title>
+    <para>
+        One of the following exit values can be returned by &p;:
+        <variablelist>
+        <varlistentry>
+            <term>0</term>
+            <listitem><para>The program finished successfully.</para></listitem>
+        </varlistentry>
+        <varlistentry>
+            <term>1</term>
+            <listitem><para>A fatal error occurred.</para></listitem>
+        </varlistentry>
+        <varlistentry>
+            <term>2</term>
+            <listitem><para>The program recovered from an error (<option>--on-error=resume</option>).</para></listitem>
+        </varlistentry>
+        </variablelist>
+    </para>
+</refsection>
+
 <refsection>
     <title>Environment</title>
     <para>

lib/cli/ocrodjvu.py

@@ -14,6 +14,7 @@
 from __future__ import print_function
 
 import argparse
+import collections
 import contextlib
 import inspect
 import locale
@@ -252,10 +253,10 @@ def __call__(self, parser, namespace, values, option_string=None):
                     print(language)
             except errors.EngineNotFound as ex:
                 logger.error(ex)
-                sys.exit(1)
+                sys.exit(errors.EXIT_FATAL)
             except errors.UnknownLanguageList as ex:
                 logger.error(ex)
-                sys.exit(1)
+                sys.exit(errors.EXIT_FATAL)
             else:
                 sys.exit(0)
 
@@ -334,6 +335,12 @@ def parse_args(self, args=None, namespace=None):
             options.n_jobs = get_cpu_count()
         return options
 
+class Results(dict):
+    seen_exception = False
+
+    def __missing__(self, key):
+        return
+
 class Context(djvu.decode.Context):
 
     def init(self, options):
@@ -430,6 +437,7 @@ def page_thread(self, pages, results, condition):
                     if self._options.resume_on_error and not interrupted_by_user:
                         # As requested by user, don't abort on error and pretend that nothing happened.
                         results[n] = False
+                        results.seen_exception = True
                         continue
                     else:
                         # The main thread will take care of aborting the application.
@@ -452,7 +460,7 @@ def _process(self, path, pages=None):
             pages = list(document.pages)
         else:
             pages = [document.pages[i - 1] for i in pages]
-        results = dict((page.n, None) for page in pages)
+        results = Results()
         condition = threading.Condition()
         threads = [
             threading.Thread(target=self.page_thread, args=(pages, results, condition))
@@ -497,7 +505,7 @@ def stop_threads():
                     for thread in threads:
                         thread.join()
                     self._debug = True
-                    sys.exit(1)
+                    sys.exit(errors.EXIT_FATAL)
                 if result is False:
                     # No image suitable for OCR.
                     pass
@@ -518,6 +526,8 @@ def stop_threads():
             raise
         finally:
             sed_file.close()
+        if results.seen_exception:
+            sys.exit(errors.EXIT_NONFATAL)
 
     def process(self, *args, **kwargs):
         try:
@@ -542,7 +552,7 @@ def main(argv=sys.argv):
         context.process(options.path, options.pages)
     except KeyboardInterrupt:
         logger.info('Interrupted by user.')
-        sys.exit(1)
+        sys.exit(errors.FATAL)
     finally:
         temp_dir = context.close()
         if temp_dir is not None:

lib/errors.py

@@ -1,6 +1,6 @@
 # encoding=UTF-8
 
-# Copyright © 2009, 2010, 2013 Jakub Wilk <jwilk@jwilk.net>
+# Copyright © 2009-2015 Jakub Wilk <jwilk@jwilk.net>
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -41,4 +41,7 @@ class MalformedHocr(MalformedOcrOutput):
     def __init__(self, message):
         Exception.__init__(self, 'Malformed hOCR document: %s' % message)
 
+EXIT_FATAL = 1
+EXIT_NONFATAL = 2
+
 # vim:ts=4 sts=4 sw=4 et