Add setting to suppress this-is-not-an-EPUB errors.

man/epubgrep.1.adoc

@@ -73,6 +73,11 @@ readable by the user.
 Read all files under each directory, recursively. Follow all symbolic
 links. Silently skips directories that are not readable by the user.
 
+*--ignore-archive-errors*::
+Ignore errors about wrong file formats. When you search directories recursively,
+it is likely that there are files which are not EPUB files. This setting
+suppresses errors related to them.
+
 == USAGE
 
 [source,shellsession]
@@ -104,12 +109,14 @@ occur more than once are merged.
 
 ==== Example configuration file
 
-This example makes epubgrep always suppress the file names on output, print 2
-words of context around matches (unless overridden on the command line) and
-search for mentions of the words thyme and oregano in every book.
+This example makes epubgrep ignore files which are not EPUB, suppress the file
+names on output, print 2 words of context around matches (unless overridden on
+the command line) and search for mentions of the words thyme and oregano in
+every book.
 
 [source,cfg]
 --------------------------------------------------------------------------------
+ignore-archive-errors
 no-filename
 context = 2
 regexp = [Tt]hyme

src/main.cpp

@@ -148,6 +148,11 @@ int main(int argc, char *argv[])
                 }
                 catch (const zip::exception &e)
                 {
+                    if (opts.ignore_archive_errors && e.code == 1)
+                    {
+                        return EXIT_SUCCESS;
+                    }
+
                     cerr << translate("ERROR: ") << e.what() << '\n';
                     cerr << format(translate("Error while searching {0:s}.")
                                        .str(),

src/options.cpp

@@ -84,6 +84,8 @@ options parse_options(int argc, char *argv[])
         ("dereference-recursive,R",
          translate("Read all files under each directory, recursively, "
                    "following symlinks.") .str().data())
+        ("ignore-archive-errors",
+         translate("Ignore errors about wrong file formats.") .str().data())
     ;
 
     po::options_description options_hidden("Hidden options");
@@ -223,6 +225,7 @@ options parse_again(const po::variables_map &vm)
     }
     opts.recursive = vm.count("recursive") > 0;
     opts.dereference_recursive = vm.count("dereference-recursive") > 0;
+    opts.ignore_archive_errors = vm.count("ignore-archive-errors") > 0;
 
     if (vm.count("regexp") > 0)
     {

src/options.hpp

@@ -54,6 +54,7 @@ struct options
     bool recursive{false};
     bool dereference_recursive{false};
     std::vector<std::string> input_file;
+    bool ignore_archive_errors{false};
 };
 
 //! Parse options and return them.