Refactor the command line option handling of the jerry tool (#1745)

The file `main-unix.c` contained a lot of recurring patterns in the
command line option handling parts. This patch removes these code
clones with the introduction of two helper functions. The goal of
the patch is to have a smaller and maintainable `jerry` tool (mostly
source-wise).

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

jerry-main/main-unix.c

@@ -123,7 +123,7 @@ gc_handler (const jerry_value_t func_obj_val __attribute__((unused)), /**< funct
 } /* gc_handler */
 
 static void
-print_usage (char *name)
+print_usage (const char *name)
 {
   jerry_port_console ("Usage: %s [OPTION]... [FILE]...\n"
                       "Try '%s --help' for more information.\n",
@@ -132,7 +132,7 @@ print_usage (char *name)
 } /* print_usage */
 
 static void
-print_help (char *name)
+print_help (const char *name)
 {
   jerry_port_console ("Usage: %s [OPTION]... [FILE]...\n"
                       "\n"
@@ -375,6 +375,49 @@ register_js_function (const char *name_p, /**< name of the function */
   jerry_release_value (result_val);
 } /* register_js_function */
 
+/**
+ * Check whether JerryScript has a requested feature enabled or not. If not,
+ * print a warning message.
+ *
+ * @return the status of the feature.
+ */
+static bool
+check_feature (jerry_feature_t feature, /**< feature to check */
+               const char *option) /**< command line option that triggered this check */
+{
+  if (!jerry_is_feature_enabled (feature))
+  {
+    jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
+    jerry_port_log (JERRY_LOG_LEVEL_WARNING, "Ignoring '%s' option because this feature is disabled!\n", option);
+    return false;
+  }
+  return true;
+} /* check_feature */
+
+/**
+ * Check whether a usage-related condition holds. If not, print an error
+ * message, print the usage, and terminate the application.
+ */
+static void
+check_usage (bool condition, /**< the condition that must hold */
+             const char *name, /**< name of the application (argv[0]) */
+             const char *msg, /**< error message to print if condition does not hold */
+             const char *opt) /**< optional part of the error message */
+{
+  if (!condition)
+  {
+    jerry_port_log (JERRY_LOG_LEVEL_ERROR, "%s", msg);
+    if (opt != NULL)
+    {
+      jerry_port_log (JERRY_LOG_LEVEL_ERROR, "%s", opt);
+    }
+    jerry_port_log (JERRY_LOG_LEVEL_ERROR, "\n");
+
+    print_usage (name);
+    exit (JERRY_STANDALONE_EXIT_CODE_FAIL);
+  }
+} /* check_usage */
+
 int
 main (int argc,
       char **argv)
@@ -423,31 +466,19 @@ main (int argc,
     }
     else if (!strcmp ("--mem-stats", argv[i]))
     {
-      if (jerry_is_feature_enabled (JERRY_FEATURE_MEM_STATS))
+      if (check_feature (JERRY_FEATURE_MEM_STATS, argv[i]))
       {
         jerry_port_default_set_log_level (JERRY_LOG_LEVEL_DEBUG);
         flags |= JERRY_INIT_MEM_STATS;
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'mem-stats' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--mem-stats-separate", argv[i]))
     {
-      if (jerry_is_feature_enabled (JERRY_FEATURE_MEM_STATS))
+      if (check_feature (JERRY_FEATURE_MEM_STATS, argv[i]))
       {
         jerry_port_default_set_log_level (JERRY_LOG_LEVEL_DEBUG);
         flags |= JERRY_INIT_MEM_STATS_SEPARATE;
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'mem-stats-separate' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--parse-only", argv[i]))
     {
@@ -455,150 +486,70 @@ main (int argc,
     }
     else if (!strcmp ("--show-opcodes", argv[i]))
     {
-      if (jerry_is_feature_enabled (JERRY_FEATURE_PARSER_DUMP))
+      if (check_feature (JERRY_FEATURE_PARSER_DUMP, argv[i]))
       {
         jerry_port_default_set_log_level (JERRY_LOG_LEVEL_DEBUG);
         flags |= JERRY_INIT_SHOW_OPCODES;
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'show-opcodes' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--show-regexp-opcodes", argv[i]))
     {
-      if (jerry_is_feature_enabled (JERRY_FEATURE_PARSER_DUMP))
+      if (check_feature (JERRY_FEATURE_REGEXP_DUMP, argv[i]))
       {
         jerry_port_default_set_log_level (JERRY_LOG_LEVEL_DEBUG);
         flags |= JERRY_INIT_SHOW_REGEXP_OPCODES;
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'show-regexp-opcodes' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--start-debug-server", argv[i]))
     {
-      if (jerry_is_feature_enabled (JERRY_FEATURE_DEBUGGER))
+      if (check_feature (JERRY_FEATURE_DEBUGGER, argv[i]))
       {
         flags |= JERRY_INIT_DEBUGGER;
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'start-debug-server' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--save-snapshot-for-global", argv[i])
              || !strcmp ("--save-snapshot-for-eval", argv[i]))
     {
-      if (++i >= argc)
+      check_usage (i + 1 < argc, argv[0], "Error: no file specified for ", argv[i]);
-      {
+      check_usage (save_snapshot_file_name_p == NULL, argv[0], "Error: snapshot file name already specified", NULL);
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: no file specified for %s\n", argv[i - 1]);
-        print_usage (argv[0]);
-        return JERRY_STANDALONE_EXIT_CODE_FAIL;
-      }
 
-      if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_SAVE))
+      if (check_feature (JERRY_FEATURE_SNAPSHOT_SAVE, argv[i++]))
       {
         is_save_snapshot_mode = true;
         is_save_snapshot_mode_for_global_or_eval = !strcmp ("--save-snapshot-for-global", argv[i - 1]);
-
-        if (save_snapshot_file_name_p != NULL)
-        {
-          jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: snapshot file name already specified\n");
-          print_usage (argv[0]);
-          return JERRY_STANDALONE_EXIT_CODE_FAIL;
-        }
-
         save_snapshot_file_name_p = argv[i];
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'save-snapshot' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--exec-snapshot", argv[i]))
     {
-      if (++i >= argc)
+      check_usage (i + 1 < argc, argv[0], "Error: no file specified for ", argv[i]);
-      {
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: no file specified for %s\n", argv[i - 1]);
-        print_usage (argv[0]);
-        return JERRY_STANDALONE_EXIT_CODE_FAIL;
-      }
 
-      if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_EXEC))
+      if (check_feature (JERRY_FEATURE_SNAPSHOT_EXEC, argv[i++]))
       {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_DEBUG);
-
         assert (exec_snapshots_count < JERRY_MAX_COMMAND_LINE_ARGS);
         exec_snapshot_file_names[exec_snapshots_count++] = argv[i];
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'exec-snapshot' option because this feature isn't enabled!\n");
-      }
     }
     else if (!strcmp ("--save-literals-list-format", argv[i])
              || !strcmp ("--save-literals-c-format", argv[i]))
     {
-      if (++i >= argc)
+      check_usage (i + 1 < argc, argv[0], "Error: no file specified for ", argv[i]);
-      {
+      check_usage (save_literals_file_name_p == NULL, argv[0], "Error: literal file name already specified", NULL);
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: no file specified for %s\n", argv[i - 1]);
-        print_usage (argv[0]);
-        return JERRY_STANDALONE_EXIT_CODE_FAIL;
-      }
 
-      if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_SAVE))
+      if (check_feature (JERRY_FEATURE_SNAPSHOT_SAVE, argv[i++]))
       {
         is_save_literals_mode = true;
         is_save_literals_mode_in_c_format_or_list = !strcmp ("--save-literals-c-format", argv[i - 1]);
-
-        if (save_literals_file_name_p != NULL)
-        {
-          jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: literal file name already specified\n");
-          print_usage (argv[0]);
-          return JERRY_STANDALONE_EXIT_CODE_FAIL;
-        }
-
         save_literals_file_name_p = argv[i];
       }
-      else
-      {
-        jerry_port_default_set_log_level (JERRY_LOG_LEVEL_WARNING);
-
-        jerry_port_log (JERRY_LOG_LEVEL_WARNING,
-                        "Ignoring 'save-literals' option because this feature is disabled!\n");
-      }
     }
     else if (!strcmp ("--log-level", argv[i]))
     {
-      if (++i >= argc)
+      check_usage (i + 1 < argc, argv[0], "Error: no level specified for ", argv[i]);
-      {
+      check_usage (strlen (argv[i + 1]) == 1 && argv[i + 1][0] >= '0' && argv[i + 1][0] <= '3',
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: no level specified for %s\n", argv[i - 1]);
+                   argv[0], "Error: wrong format for ", argv[i]);
-        print_usage (argv[0]);
-        return JERRY_STANDALONE_EXIT_CODE_FAIL;
-      }
 
-      if (strlen (argv[i]) != 1 || argv[i][0] < '0' || argv[i][0] > '3')
+      jerry_port_default_set_log_level ((jerry_log_level_t) (argv[++i][0] - '0'));
-      {
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: wrong format for %s\n", argv[i - 1]);
-        print_usage (argv[0]);
-        return JERRY_STANDALONE_EXIT_CODE_FAIL;
-      }
-
-      jerry_port_default_set_log_level ((jerry_log_level_t) (argv[i][0] - '0'));
     }
     else if (!strcmp ("--abort-on-fail", argv[i]))
     {
@@ -614,9 +565,7 @@ main (int argc,
     }
     else if (!strncmp ("-", argv[i], 1))
     {
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: unrecognized option: %s\n", argv[i]);
+      check_usage (false, argv[0], "Error: unrecognized option: %s\n", argv[i]);
-      print_usage (argv[0]);
-      return JERRY_STANDALONE_EXIT_CODE_FAIL;
     }
     else
     {
@@ -624,31 +573,18 @@ main (int argc,
     }
   }
 
-  if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_SAVE) && is_save_snapshot_mode)
+  if (is_save_snapshot_mode)
   {
-    if (files_counter != 1)
+    check_usage (files_counter == 1,
-    {
+                 argv[0], "Error: --save-snapshot-* options work with exactly one script", NULL);
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR,
+    check_usage (exec_snapshots_count == 0,
-                      "Error: --save-snapshot argument works with exactly one script\n");
+                 argv[0], "Error: --save-snapshot-* and --exec-snapshot options can't be passed simultaneously", NULL);
-      return JERRY_STANDALONE_EXIT_CODE_FAIL;
-    }
-
-    if (exec_snapshots_count != 0)
-    {
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR,
-                      "Error: --save-snapshot and --exec-snapshot options can't be passed simultaneously\n");
-      return JERRY_STANDALONE_EXIT_CODE_FAIL;
-    }
   }
 
-  if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_SAVE) && is_save_literals_mode)
+  if (is_save_literals_mode)
   {
-    if (files_counter != 1)
+    check_usage (files_counter == 1,
-    {
+                argv[0], "Error: --save-literals-* options work with exactly one script", NULL);
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR,
-                      "Error: --save-literals-* options work with exactly one script\n");
-      return JERRY_STANDALONE_EXIT_CODE_FAIL;
-    }
   }
 
   if (files_counter == 0
@@ -711,7 +647,7 @@ main (int argc,
         break;
       }
 
-      if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_SAVE) && (is_save_snapshot_mode || is_save_literals_mode))
+      if (is_save_snapshot_mode || is_save_literals_mode)
       {
         static uint32_t snapshot_save_buffer[ JERRY_SNAPSHOT_BUFFER_SIZE ];