refactor(fileio): remove API shell layer encouraging unnecessary allocations

Functions like file_open_new() and file_open_fd_new() which just is a
wrapper around the real functions but with an extra xmalloc/xfree around
is an anti-pattern. If the caller really needs to allocate a
FileDescriptor as a heap object, it can do that directly.

FileDescriptor by itself is pretty much a pointer, or rather two:
the OS fd index and a pointer to a buffer. So most of the time an extra
pointer layer is just wasteful.

In the case of scriptin[curscript] in getchar.c, curscript used
to mean in practice:

N+1 open scripts           when curscript>0
zero or one open scripts   when curscript==0

Which means scriptin[0] had to be compared to NULL to disambiguate the
curscript=0 case.

Instead, use curscript==-1 to mean that are no script,
then all pointer comparisons dissappear and we can just use an array of
structs without extra pointers.

1 files changed, 13 insertions, 32 deletions

diff --git a/src/nvim/main.c b/src/nvim/main.c
index e18c561879..c2445437e6 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -426,7 +426,19 @@ int main(int argc, char **argv)
     params.edit_type = EDIT_STDIN;
   }
 
-  open_script_files(&params);
+  if (params.scriptin) {
+    if (!open_scriptin(params.scriptin)) {
+      os_exit(2);
+    }
+  }
+  if (params.scriptout) {
+    scriptout = os_fopen(params.scriptout, params.scriptout_append ? APPENDBIN : WRITEBIN);
+    if (scriptout == NULL) {
+      fprintf(stderr, _("Cannot open for script output: \""));
+      fprintf(stderr, "%s\"\n", params.scriptout);
+      os_exit(2);
+    }
+  }
 
   nlua_init_defaults();
 
@@ -1620,37 +1632,6 @@ static void read_stdin(void)
   check_swap_exists_action();
 }
 
-static void open_script_files(mparm_T *parmp)
-{
-  if (parmp->scriptin) {
-    int error;
-    if (strequal(parmp->scriptin, "-")) {
-      FileDescriptor *stdin_dup = file_open_stdin();
-      scriptin[0] = stdin_dup;
-    } else {
-      scriptin[0] = file_open_new(&error, parmp->scriptin,
-                                  kFileReadOnly|kFileNonBlocking, 0);
-      if (scriptin[0] == NULL) {
-        vim_snprintf(IObuff, IOSIZE,
-                     _("Cannot open for reading: \"%s\": %s\n"),
-                     parmp->scriptin, os_strerror(error));
-        fprintf(stderr, "%s", IObuff);
-        os_exit(2);
-      }
-    }
-    save_typebuf();
-  }
-
-  if (parmp->scriptout) {
-    scriptout = os_fopen(parmp->scriptout, parmp->scriptout_append ? APPENDBIN : WRITEBIN);
-    if (scriptout == NULL) {
-      fprintf(stderr, _("Cannot open for script output: \""));
-      fprintf(stderr, "%s\"\n", parmp->scriptout);
-      os_exit(2);
-    }
-  }
-}
-
 // Create the requested number of windows and edit buffers in them.
 // Also does recovery if "recoverymode" set.
 static void create_windows(mparm_T *parmp)