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

1 files changed, 72 insertions, 136 deletions

diff --git a/jerry-main/main-unix.c b/jerry-main/main-unix.c
index 7910ab12..c3555f8b 100644
--- a/jerry-main/main-unix.c
+++ b/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)
-      {
-        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;
-      }
+      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);
 
-      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)
-      {
-        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;
-      }
+      check_usage (i + 1 < argc, argv[0], "Error: no file specified for ", argv[i]);
 
-      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)
-      {
-        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;
-      }
+      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);
 
-      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)
-      {
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Error: no level specified for %s\n", argv[i - 1]);
-        print_usage (argv[0]);
-        return JERRY_STANDALONE_EXIT_CODE_FAIL;
-      }
+      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',
+                   argv[0], "Error: wrong format for ", argv[i]);
 
-      if (strlen (argv[i]) != 1 || argv[i][0] < '0' || argv[i][0] > '3')
-      {
-        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'));
+      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]);
-      print_usage (argv[0]);
-      return JERRY_STANDALONE_EXIT_CODE_FAIL;
+      check_usage (false, argv[0], "Error: unrecognized option: %s\n", argv[i]);
     }
     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)
-    {
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR,
-                      "Error: --save-snapshot argument works with exactly one script\n");
-      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;
-    }
+    check_usage (files_counter == 1,
+                 argv[0], "Error: --save-snapshot-* options work with exactly one script", NULL);
+    check_usage (exec_snapshots_count == 0,
+                 argv[0], "Error: --save-snapshot-* and --exec-snapshot options can't be passed simultaneously", NULL);
   }
 
-  if (jerry_is_feature_enabled (JERRY_FEATURE_SNAPSHOT_SAVE) && is_save_literals_mode)
+  if (is_save_literals_mode)
   {
-    if (files_counter != 1)
-    {
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR,
-                      "Error: --save-literals-* options work with exactly one script\n");
-      return JERRY_STANDALONE_EXIT_CODE_FAIL;
-    }
+    check_usage (files_counter == 1,
+                argv[0], "Error: --save-literals-* options work with exactly one script", NULL);
   }
 
   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 ];