refactor(options): remove `.indir`, redesign option scopes #31066

Problem:
The way option scopes currently work is inflexible and does not allow for nested
option scopes or easily finding the value of an option at any arbitrary scope
without having to do long handwritten switch-case statements like in
`get_varp()`. `.indir` is also confusing and redundant since option indices for
each scope can be autogenerated.

Solution:
Expand option scopes in such a way that an option can support any amount of
scopes using a set of scope flags, similarly to how it's already done for option
types. Also make options contain information about its index at each scope it
supports. This allows for massively simplifying `get_varp()` and
`get_varp_scope()` in the future by just using a struct for options at each
scope. This would be done by creating a table that stores the offset of an
option's variable at a scope by using the option's index at that scope as a key.
This PR also autogenerates enums for option indices at each scope to remove the
need for `.indir` entirely, and also to allow easily iterating over options all
options that support any scope.

Ref: #29314

1 files changed, 15 insertions, 45 deletions

diff --git a/src/nvim/api/deprecated.c b/src/nvim/api/deprecated.c
index b3ba832fec..b38a7d4173 100644
--- a/src/nvim/api/deprecated.c
+++ b/src/nvim/api/deprecated.c
@@ -533,7 +533,7 @@ void nvim_set_option(uint64_t channel_id, String name, Object value, Error *err)
   FUNC_API_SINCE(1)
   FUNC_API_DEPRECATED_SINCE(11)
 {
-  set_option_to(channel_id, NULL, kOptReqGlobal, name, value, err);
+  set_option_to(channel_id, NULL, kOptScopeGlobal, name, value, err);
 }
 
 /// Gets the global value of an option.
@@ -546,7 +546,7 @@ Object nvim_get_option(String name, Error *err)
   FUNC_API_SINCE(1)
   FUNC_API_DEPRECATED_SINCE(11)
 {
-  return get_option_from(NULL, kOptReqGlobal, name, err);
+  return get_option_from(NULL, kOptScopeGlobal, name, err);
 }
 
 /// Gets a buffer option value
@@ -566,7 +566,7 @@ Object nvim_buf_get_option(Buffer buffer, String name, Error *err)
     return (Object)OBJECT_INIT;
   }
 
-  return get_option_from(buf, kOptReqBuf, name, err);
+  return get_option_from(buf, kOptScopeBuf, name, err);
 }
 
 /// Sets a buffer option value. Passing `nil` as value deletes the option (only
@@ -588,7 +588,7 @@ void nvim_buf_set_option(uint64_t channel_id, Buffer buffer, String name, Object
     return;
   }
 
-  set_option_to(channel_id, buf, kOptReqBuf, name, value, err);
+  set_option_to(channel_id, buf, kOptScopeBuf, name, value, err);
 }
 
 /// Gets a window option value
@@ -608,7 +608,7 @@ Object nvim_win_get_option(Window window, String name, Error *err)
     return (Object)OBJECT_INIT;
   }
 
-  return get_option_from(win, kOptReqWin, name, err);
+  return get_option_from(win, kOptScopeWin, name, err);
 }
 
 /// Sets a window option value. Passing `nil` as value deletes the option (only
@@ -630,48 +630,18 @@ void nvim_win_set_option(uint64_t channel_id, Window window, String name, Object
     return;
   }
 
-  set_option_to(channel_id, win, kOptReqWin, name, value, err);
-}
-
-/// Check if option has a value in the requested scope.
-///
-/// @param  opt_idx    Option index in options[] table.
-/// @param  req_scope  Requested option scope. See OptReqScope in option.h.
-///
-/// @return  true if option has a value in the requested scope, false otherwise.
-static bool option_has_scope(OptIndex opt_idx, OptReqScope req_scope)
-{
-  if (opt_idx == kOptInvalid) {
-    return false;
-  }
-
-  vimoption_T *opt = get_option(opt_idx);
-
-  // TTY option.
-  if (is_tty_option(opt->fullname)) {
-    return req_scope == kOptReqGlobal;
-  }
-
-  switch (req_scope) {
-  case kOptReqGlobal:
-    return opt->var != VAR_WIN;
-  case kOptReqBuf:
-    return opt->indir & PV_BUF;
-  case kOptReqWin:
-    return opt->indir & PV_WIN;
-  }
-  UNREACHABLE;
+  set_option_to(channel_id, win, kOptScopeWin, name, value, err);
 }
 
 /// Gets the value of a global or local (buffer, window) option.
 ///
 /// @param[in]   from       Pointer to buffer or window for local option value.
-/// @param       req_scope  Requested option scope. See OptReqScope in option.h.
+/// @param       req_scope  Requested option scope. See OptScope in option.h.
 /// @param       name       The option name.
 /// @param[out]  err        Details of an error that may have occurred.
 ///
 /// @return  the option value.
-static Object get_option_from(void *from, OptReqScope req_scope, String name, Error *err)
+static Object get_option_from(void *from, OptScope req_scope, String name, Error *err)
 {
   VALIDATE_S(name.size > 0, "option name", "<empty>", {
     return (Object)OBJECT_INIT;
@@ -681,7 +651,7 @@ static Object get_option_from(void *from, OptReqScope req_scope, String name, Er
   OptVal value = NIL_OPTVAL;
 
   if (option_has_scope(opt_idx, req_scope)) {
-    value = get_option_value_for(opt_idx, req_scope == kOptReqGlobal ? OPT_GLOBAL : OPT_LOCAL,
+    value = get_option_value_for(opt_idx, req_scope == kOptScopeGlobal ? OPT_GLOBAL : OPT_LOCAL,
                                  req_scope, from, err);
     if (ERROR_SET(err)) {
       return (Object)OBJECT_INIT;
@@ -698,11 +668,11 @@ static Object get_option_from(void *from, OptReqScope req_scope, String name, Er
 /// Sets the value of a global or local (buffer, window) option.
 ///
 /// @param[in]   to         Pointer to buffer or window for local option value.
-/// @param       req_scope  Requested option scope. See OptReqScope in option.h.
+/// @param       req_scope  Requested option scope. See OptScope in option.h.
 /// @param       name       The option name.
 /// @param       value      New option value.
 /// @param[out]  err        Details of an error that may have occurred.
-static void set_option_to(uint64_t channel_id, void *to, OptReqScope req_scope, String name,
+static void set_option_to(uint64_t channel_id, void *to, OptScope req_scope, String name,
                           Object value, Error *err)
 {
   VALIDATE_S(name.size > 0, "option name", "<empty>", {
@@ -725,12 +695,12 @@ static void set_option_to(uint64_t channel_id, void *to, OptReqScope req_scope,
     return;
   });
 
-  int attrs = get_option_attrs(opt_idx);
   // For global-win-local options -> setlocal
   // For        win-local options -> setglobal and setlocal (opt_flags == 0)
-  const int opt_flags = (req_scope == kOptReqWin && !(attrs & SOPT_GLOBAL))
-                        ? 0
-                        : (req_scope == kOptReqGlobal) ? OPT_GLOBAL : OPT_LOCAL;
+  const int opt_flags
+    = (req_scope == kOptScopeWin && !option_has_scope(opt_idx, kOptScopeGlobal))
+      ? 0
+      : ((req_scope == kOptScopeGlobal) ? OPT_GLOBAL : OPT_LOCAL);
 
   WITH_SCRIPT_CONTEXT(channel_id, {
     set_option_value_for(name.data, opt_idx, optval, opt_flags, req_scope, to, err);