Add `mrb_get_arg1()` that retrieves single (and only) argument.

`mrb_get_arg1()` raises `ArgumentError` if the method does not receive one
argument.

And replaces all `mrb_get_args(mrb, "o", &arg)` by the new function.

3 files changed, 11 insertions, 30 deletions

diff --git a/mrbgems/mruby-io/src/file.c b/mrbgems/mruby-io/src/file.c
index dd65e2da9..6c99300d8 100644
--- a/mrbgems/mruby-io/src/file.c
+++ b/mrbgems/mruby-io/src/file.c
@@ -492,10 +492,9 @@ mrb_file_truncate(mrb_state *mrb, mrb_value self)
 {
   int fd;
   mrb_int length;
-  mrb_value lenv;
+  mrb_value lenv = mrb_get_arg1(mrb);
 
   fd = mrb_io_fileno(mrb, self);
-  mrb_get_args(mrb, "o", &lenv);
   length = mrb_int(mrb, lenv);
   if (mrb_ftruncate(fd, length) != 0) {
     mrb_raise(mrb, E_IO_ERROR, "ftruncate failed");
diff --git a/mrbgems/mruby-io/src/file_test.c b/mrbgems/mruby-io/src/file_test.c
index 19fd5739b..b7a28f4d3 100644
--- a/mrbgems/mruby-io/src/file_test.c
+++ b/mrbgems/mruby-io/src/file_test.c
@@ -93,9 +93,7 @@ mrb_filetest_s_directory_p(mrb_state *mrb, mrb_value klass)
 #endif
 
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_false_value();
@@ -124,9 +122,7 @@ mrb_filetest_s_pipe_p(mrb_state *mrb, mrb_value klass)
 #  endif
 
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_false_value();
@@ -167,9 +163,7 @@ mrb_filetest_s_symlink_p(mrb_state *mrb, mrb_value klass)
 
 #ifdef S_ISLNK
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_lstat(mrb, obj, &st) == -1)
     return mrb_false_value();
@@ -210,9 +204,7 @@ mrb_filetest_s_socket_p(mrb_state *mrb, mrb_value klass)
 
 #ifdef S_ISSOCK
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_false_value();
@@ -236,9 +228,8 @@ static mrb_value
 mrb_filetest_s_exist_p(mrb_state *mrb, mrb_value klass)
 {
   struct stat st;
-  mrb_value obj;
+  mrb_value obj = mrb_get_arg1(mrb);
 
-  mrb_get_args(mrb, "o", &obj);
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_false_value();
 
@@ -261,9 +252,7 @@ mrb_filetest_s_file_p(mrb_state *mrb, mrb_value klass)
 #endif
 
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_false_value();
@@ -285,9 +274,7 @@ static mrb_value
 mrb_filetest_s_zero_p(mrb_state *mrb, mrb_value klass)
 {
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_false_value();
@@ -310,9 +297,7 @@ static mrb_value
 mrb_filetest_s_size(mrb_state *mrb, mrb_value klass)
 {
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     mrb_sys_fail(mrb, "mrb_stat");
@@ -332,9 +317,7 @@ static mrb_value
 mrb_filetest_s_size_p(mrb_state *mrb, mrb_value klass)
 {
   struct stat st;
-  mrb_value obj;
-
-  mrb_get_args(mrb, "o", &obj);
+  mrb_value obj = mrb_get_arg1(mrb);
 
   if (mrb_stat(mrb, obj, &st) < 0)
     return mrb_nil_value();
diff --git a/mrbgems/mruby-io/src/io.c b/mrbgems/mruby-io/src/io.c
index ef1283b51..505ceb248 100644
--- a/mrbgems/mruby-io/src/io.c
+++ b/mrbgems/mruby-io/src/io.c
@@ -599,13 +599,12 @@ mrb_dup(mrb_state *mrb, int fd, mrb_bool *failed)
 static mrb_value
 mrb_io_initialize_copy(mrb_state *mrb, mrb_value copy)
 {
-  mrb_value orig;
+  mrb_value orig = mrb_get_arg1(mrb);
   mrb_value buf;
   struct mrb_io *fptr_copy;
   struct mrb_io *fptr_orig;
   mrb_bool failed = TRUE;
 
-  mrb_get_args(mrb, "o", &orig);
   fptr_orig = io_get_open_fptr(mrb, orig);
   fptr_copy = (struct mrb_io *)DATA_PTR(copy);
   if (fptr_orig == fptr_copy) return copy;