refactor(options): use hashy for finding options (#26573)

Problem:
`findoption()` searches through the options[] table linearly for option
names, even though hashy can be used to generate a compile-time hash
table for it.

Solution:
Use hashy to generate a compile time hash table for finding options.
This also allows handling option aliases, so we don't need separate
options[] table entries for things like 'viminfo'.

10 files changed, 124 insertions, 138 deletions

diff --git a/src/nvim/CMakeLists.txt b/src/nvim/CMakeLists.txt
index 3773168948..a21a87ad5e 100644
--- a/src/nvim/CMakeLists.txt
+++ b/src/nvim/CMakeLists.txt
@@ -303,10 +303,12 @@ set(GENERATED_EVENTS_ENUM ${GENERATED_INCLUDES_DIR}/auevents_enum.generated.h)
 set(GENERATED_EVENTS_NAMES_MAP ${GENERATED_DIR}/auevents_name_map.generated.h)
 set(GENERATED_OPTIONS ${GENERATED_DIR}/options.generated.h)
 set(GENERATED_OPTIONS_ENUM ${GENERATED_DIR}/options_enum.generated.h)
+set(GENERATED_OPTIONS_MAP ${GENERATED_DIR}/options_map.generated.h)
 set(EX_CMDS_GENERATOR ${GENERATOR_DIR}/gen_ex_cmds.lua)
 set(FUNCS_GENERATOR ${GENERATOR_DIR}/gen_eval.lua)
 set(EVENTS_GENERATOR ${GENERATOR_DIR}/gen_events.lua)
 set(OPTIONS_GENERATOR ${GENERATOR_DIR}/gen_options.lua)
+set(OPTIONS_ENUM_GENERATOR ${GENERATOR_DIR}/gen_options_enum.lua)
 set(UNICODE_TABLES_GENERATOR ${GENERATOR_DIR}/gen_unicode_tables.lua)
 set(UNICODE_DIR ${PROJECT_SOURCE_DIR}/src/unicode)
 set(GENERATED_UNICODE_TABLES ${GENERATED_DIR}/unicode_tables.generated.h)
@@ -615,6 +617,7 @@ list(APPEND NVIM_GENERATED_FOR_HEADERS
   "${GENERATED_EX_CMDS_ENUM}"
   "${GENERATED_EVENTS_ENUM}"
   "${GENERATED_KEYSETS_DEFS}"
+  "${GENERATED_OPTIONS_ENUM}"
 )
 
 list(APPEND NVIM_GENERATED_FOR_SOURCES
@@ -622,6 +625,7 @@ list(APPEND NVIM_GENERATED_FOR_SOURCES
   "${GENERATED_EX_CMDS_DEFS}"
   "${GENERATED_EVENTS_NAMES_MAP}"
   "${GENERATED_OPTIONS}"
+  "${GENERATED_OPTIONS_MAP}"
   "${GENERATED_UNICODE_TABLES}"
   "${VIM_MODULE_FILE}"
 )
@@ -647,11 +651,16 @@ add_custom_command(OUTPUT ${GENERATED_EVENTS_ENUM} ${GENERATED_EVENTS_NAMES_MAP}
   DEPENDS ${LUA_GEN_DEPS} ${EVENTS_GENERATOR} ${CMAKE_CURRENT_LIST_DIR}/auevents.lua
 )
 
-add_custom_command(OUTPUT ${GENERATED_OPTIONS} ${GENERATED_OPTIONS_ENUM}
-  COMMAND ${LUA_GEN} ${OPTIONS_GENERATOR} ${GENERATED_OPTIONS} ${GENERATED_OPTIONS_ENUM}
+add_custom_command(OUTPUT ${GENERATED_OPTIONS}
+  COMMAND ${LUA_GEN} ${OPTIONS_GENERATOR} ${GENERATED_OPTIONS}
   DEPENDS ${LUA_GEN_DEPS} ${OPTIONS_GENERATOR} ${CMAKE_CURRENT_LIST_DIR}/options.lua
 )
 
+add_custom_command(OUTPUT ${GENERATED_OPTIONS_ENUM} ${GENERATED_OPTIONS_MAP}
+  COMMAND ${LUA_GEN} ${OPTIONS_ENUM_GENERATOR} ${GENERATED_OPTIONS_ENUM} ${GENERATED_OPTIONS_MAP}
+  DEPENDS ${LUA_GEN_DEPS} ${OPTIONS_ENUM_GENERATOR} ${CMAKE_CURRENT_LIST_DIR}/options.lua
+)
+
 # NVIM_GENERATED_FOR_SOURCES and NVIM_GENERATED_FOR_HEADERS must be mutually exclusive.
 foreach(hfile ${NVIM_GENERATED_FOR_HEADERS})
   list(FIND NVIM_GENERATED_FOR_SOURCES ${hfile} hfile_idx)
diff --git a/src/nvim/api/deprecated.c b/src/nvim/api/deprecated.c
index 371361c5a1..27af581ef4 100644
--- a/src/nvim/api/deprecated.c
+++ b/src/nvim/api/deprecated.c
@@ -643,7 +643,7 @@ static Object get_option_from(void *from, OptReqScope req_scope, String name, Er
     return (Object)OBJECT_INIT;
   });
 
-  OptVal value = get_option_value_strict(findoption(name.data), req_scope, from, err);
+  OptVal value = get_option_value_strict(find_option(name.data), req_scope, from, err);
   if (ERROR_SET(err)) {
     return (Object)OBJECT_INIT;
   }
@@ -669,7 +669,7 @@ static void set_option_to(uint64_t channel_id, void *to, OptReqScope req_scope,
     return;
   });
 
-  OptIndex opt_idx = findoption(name.data);
+  OptIndex opt_idx = find_option(name.data);
   VALIDATE_S(opt_idx != kOptInvalid, "option name", name.data, {
     return;
   });
diff --git a/src/nvim/api/options.c b/src/nvim/api/options.c
index 54a2fbf385..a3ea7d9d47 100644
--- a/src/nvim/api/options.c
+++ b/src/nvim/api/options.c
@@ -79,7 +79,7 @@ static int validate_option_value_args(Dict(option) *opts, char *name, OptIndex *
     return FAIL;
   });
 
-  *opt_idxp = findoption(name);
+  *opt_idxp = find_option(name);
   int flags = get_option_attrs(*opt_idxp);
   if (flags == 0) {
     // hidden or unknown option
diff --git a/src/nvim/eval/vars.c b/src/nvim/eval/vars.c
index 6fd707a0b0..9897ca77f1 100644
--- a/src/nvim/eval/vars.c
+++ b/src/nvim/eval/vars.c
@@ -1943,7 +1943,7 @@ typval_T optval_as_tv(OptVal value, bool numbool)
 /// Set option "varname" to the value of "varp" for the current buffer/window.
 static void set_option_from_tv(const char *varname, typval_T *varp)
 {
-  OptIndex opt_idx = findoption(varname);
+  OptIndex opt_idx = find_option(varname);
   if (opt_idx == kOptInvalid) {
     semsg(_(e_unknown_option2), varname);
     return;
diff --git a/src/nvim/generators/gen_options.lua b/src/nvim/generators/gen_options.lua
index 61d5df3c84..2fd11e4c58 100644
--- a/src/nvim/generators/gen_options.lua
+++ b/src/nvim/generators/gen_options.lua
@@ -1,5 +1,4 @@
 local options_file = arg[1]
-local options_enum_file = arg[2]
 
 local opt_fd = assert(io.open(options_file, 'w'))
 
@@ -171,7 +170,7 @@ local function dump_option(i, o)
   end
   if o.varname then
     w('    .var=&' .. o.varname)
-  -- Immutable options should directly point to the default value
+  -- Immutable options can directly point to the default value.
   elseif o.immutable then
     w(('    .var=&options[%u].def_val'):format(i - 1))
   elseif #o.scope == 1 and o.scope[1] == 'window' then
@@ -248,19 +247,3 @@ w('')
 for _, v in ipairs(defines) do
   w('#define ' .. v[1] .. ' ' .. v[2])
 end
-
--- Generate options enum file
-opt_fd = assert(io.open(options_enum_file, 'w'))
-
-w('typedef enum {')
-w('  kOptInvalid = -1,')
-
-for i, o in ipairs(options.options) do
-  w(('  kOpt%s = %u,'):format(lowercase_to_titlecase(o.full_name), i - 1))
-end
-
-w('  // Option count, used when iterating through options')
-w('#define kOptIndexCount ' .. tostring(#options.options))
-w('} OptIndex;')
-
-opt_fd:close()
diff --git a/src/nvim/generators/gen_options_enum.lua b/src/nvim/generators/gen_options_enum.lua
new file mode 100644
index 0000000000..c3fe9baae6
--- /dev/null
+++ b/src/nvim/generators/gen_options_enum.lua
@@ -0,0 +1,76 @@
+-- Generates option index enum and map of option name to option index.
+-- Handles option full name, short name and aliases.
+
+local options_enum_file = arg[1]
+local options_map_file = arg[2]
+local options_enum_fd = assert(io.open(options_enum_file, 'w'))
+local options_map_fd = assert(io.open(options_map_file, 'w'))
+
+--- @param s string
+local function enum_w(s)
+  options_enum_fd:write(s .. '\n')
+end
+
+--- @param s string
+local function map_w(s)
+  options_map_fd:write(s .. '\n')
+end
+
+--- @param s string
+--- @return string
+local lowercase_to_titlecase = function(s)
+  return s:sub(1, 1):upper() .. s:sub(2)
+end
+
+--- @type vim.option_meta[]
+local options = require('options').options
+--- @type { [string]: string }
+local option_index = {}
+
+-- Generate option index enum and populate the `option_index` dictionary.
+enum_w('typedef enum {')
+enum_w('  kOptInvalid = -1,')
+
+for i, o in ipairs(options) do
+  local enum_val_name = 'kOpt' .. lowercase_to_titlecase(o.full_name)
+  enum_w(('  %s = %u,'):format(enum_val_name, i - 1))
+
+  option_index[o.full_name] = enum_val_name
+
+  if o.abbreviation then
+    option_index[o.abbreviation] = enum_val_name
+  end
+
+  if o.alias then
+    o.alias = type(o.alias) == 'string' and { o.alias } or o.alias
+
+    for _, v in ipairs(o.alias) do
+      option_index[v] = enum_val_name
+    end
+  end
+end
+
+enum_w('  // Option count, used when iterating through options')
+enum_w('#define kOptIndexCount ' .. tostring(#options))
+enum_w('} OptIndex;')
+enum_w('')
+
+options_enum_fd:close()
+
+--- Generate option index map.
+local hashy = require('generators.hashy')
+local neworder, hashfun = hashy.hashy_hash('find_option', vim.tbl_keys(option_index), function(idx)
+  return ('option_hash_elems[%s].name'):format(idx)
+end)
+
+map_w('static const struct { const char *name; OptIndex opt_idx; } option_hash_elems[] = {')
+
+for _, name in ipairs(neworder) do
+  assert(option_index[name] ~= nil)
+  map_w(('  { .name = "%s", .opt_idx = %s },'):format(name, option_index[name]))
+end
+
+map_w('};\n')
+map_w('static ' .. hashfun)
+
+options_map_fd:close()
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 1f4f547759..0d0437d45f 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -1,8 +1,8 @@
 // User-settable options. Checklist for adding a new option:
 // - Put it in options.lua
-// - For a global option: Add a variable for it in option_defs.h.
+// - For a global option: Add a variable for it in option_vars.h.
 // - For a buffer or window local option:
-//   - Add a BV_XX or WV_XX entry to option_defs.h
+//   - Add a BV_XX or WV_XX entry to option_vars.h
 //   - Add a variable to the window or buffer struct in buffer_defs.h.
 //   - For a window option, add some code to copy_winopt().
 //   - For a window string option, add code to check_winopt()
@@ -12,7 +12,7 @@
 //   - For a buffer string option, add code to check_buf_options().
 // - If it's a numeric option, add any necessary bounds checks to check_num_option_bounds().
 // - If it's a list of flags, add some code in do_set(), search for WW_ALL.
-// - Add documentation! doc/options.txt, and any other related places.
+// - Add documentation! "desc" in options.lua, and any other related places.
 // - Add an entry in runtime/optwin.vim.
 
 #define IN_OPTION_C
@@ -143,15 +143,13 @@ typedef enum {
 # include "option.c.generated.h"
 #endif
 
-// options[] is initialized here.
-// The order of the options MUST be alphabetic for ":set all" and findoption().
-// All option names MUST start with a lowercase letter (for findoption()).
-// Exception: "t_" options are at the end.
+// options[] is initialized in options.generated.h.
 // The options with a NULL variable are 'hidden': a set command for them is
 // ignored and they are not printed.
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "options.generated.h"
+# include "options_map.generated.h"
 #endif
 
 static int p_bin_dep_opts[] = {
@@ -664,7 +662,7 @@ void set_init_3(void)
   }
 
   if (buf_is_empty(curbuf)) {
-    int idx_ffs = findoption_len(S_LEN("ffs"));
+    int idx_ffs = find_option("ffs");
 
     // Apply the first entry of 'fileformats' to the initial buffer.
     if (idx_ffs >= 0 && (options[idx_ffs].flags & P_WAS_SET)) {
@@ -1132,7 +1130,7 @@ const char *find_option_end(const char *arg, OptIndex *opt_idxp)
     p++;
   }
 
-  *opt_idxp = findoption_len(arg, (size_t)(p - arg));
+  *opt_idxp = find_option_len(arg, (size_t)(p - arg));
   return p;
 }
 
@@ -3009,87 +3007,6 @@ void check_redraw(uint32_t flags)
   check_redraw_for(curbuf, curwin, flags);
 }
 
-/// Find index for named option
-///
-/// @param[in]  arg  Option to find index for.
-/// @param[in]  len  Length of the option.
-///
-/// @return Index of the option or kOptInvalid if option was not found.
-OptIndex findoption_len(const char *const arg, const size_t len)
-{
-  const char *s;
-  static int quick_tab[27] = { 0, 0 };  // quick access table
-
-  // For first call: Initialize the quick-access table.
-  // It contains the index for the first option that starts with a certain
-  // letter.  There are 26 letters, plus the first "t_" option.
-  if (quick_tab[1] == 0) {
-    const char *p = options[0].fullname;
-    for (OptIndex i = 1; i < kOptIndexCount; i++) {
-      s = options[i].fullname;
-
-      if (s[0] != p[0]) {
-        if (s[0] == 't' && s[1] == '_') {
-          quick_tab[26] = i;
-        } else {
-          quick_tab[CHAR_ORD_LOW(s[0])] = i;
-        }
-      }
-      p = s;
-    }
-  }
-
-  // Check for name starting with an illegal character.
-  if (len == 0 || arg[0] < 'a' || arg[0] > 'z') {
-    return kOptInvalid;
-  }
-
-  OptIndex opt_idx;
-  const bool is_term_opt = (len > 2 && arg[0] == 't' && arg[1] == '_');
-  if (is_term_opt) {
-    opt_idx = quick_tab[26];
-  } else {
-    opt_idx = quick_tab[CHAR_ORD_LOW(arg[0])];
-  }
-  // Match full name
-  for (; opt_idx < kOptIndexCount; opt_idx++) {
-    s = options[opt_idx].fullname;
-
-    // Break if first character no longer matches.
-    if (s[0] != arg[0]) {
-      opt_idx = kOptIndexCount;
-      break;
-    }
-
-    if (strncmp(arg, s, len) == 0 && s[len] == NUL) {
-      break;
-    }
-  }
-  if (opt_idx == kOptIndexCount && !is_term_opt) {
-    opt_idx = quick_tab[CHAR_ORD_LOW(arg[0])];
-    // Match short name
-    for (; opt_idx < kOptIndexCount; opt_idx++) {
-      s = options[opt_idx].shortname;
-      if (s != NULL && strncmp(arg, s, len) == 0 && s[len] == NUL) {
-        break;
-      }
-    }
-  }
-  if (opt_idx == kOptIndexCount) {
-    opt_idx = kOptInvalid;
-  } else {
-    // Nvim: handle option aliases.
-    if (strncmp(options[opt_idx].fullname, "viminfo", 7) == 0) {
-      if (strlen(options[opt_idx].fullname) == 7) {
-        return findoption_len("shada", 5);
-      }
-      assert(strcmp(options[opt_idx].fullname, "viminfofile") == 0);
-      return findoption_len("shadafile", 9);
-    }
-  }
-  return opt_idx;
-}
-
 bool is_tty_option(const char *name)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
@@ -3147,15 +3064,28 @@ bool set_tty_option(const char *name, char *value)
   return false;
 }
 
+/// Find index for an option. Don't go beyond `len` length.
+///
+/// @param[in]  name  Option name.
+/// @param      len   Option name length.
+///
+/// @return Option index or kOptInvalid if option was not found.
+OptIndex find_option_len(const char *const name, size_t len)
+  FUNC_ATTR_NONNULL_ALL
+{
+  int index = find_option_hash(name, len);
+  return index >= 0 ? option_hash_elems[index].opt_idx : kOptInvalid;
+}
+
 /// Find index for an option.
 ///
-/// @param[in]  arg  Option name.
+/// @param[in]  name  Option name.
 ///
 /// @return Option index or kOptInvalid if option was not found.
-OptIndex findoption(const char *const arg)
+OptIndex find_option(const char *const name)
   FUNC_ATTR_NONNULL_ALL
 {
-  return findoption_len(arg, strlen(arg));
+  return find_option_len(name, strlen(name));
 }
 
 /// Free an allocated OptVal.
@@ -5229,7 +5159,7 @@ void set_context_in_set_cmd(expand_T *xp, char *arg, int opt_flags)
         return;
       }
       nextchar = *p;
-      opt_idx = findoption_len(arg, (size_t)(p - arg));
+      opt_idx = find_option_len(arg, (size_t)(p - arg));
       if (opt_idx == kOptInvalid || options[opt_idx].var == NULL) {
         xp->xp_context = EXPAND_NOTHING;
         return;
@@ -5534,7 +5464,7 @@ int ExpandOldSetting(int *numMatches, char ***matches)
 
   // For a terminal key code expand_option_idx is kOptInvalid.
   if (expand_option_idx == kOptInvalid) {
-    expand_option_idx = findoption(expand_option_name);
+    expand_option_idx = find_option(expand_option_name);
   }
 
   if (expand_option_idx != kOptInvalid) {
@@ -6146,7 +6076,7 @@ int get_sidescrolloff_value(win_T *wp)
 
 Dictionary get_vimoption(String name, int scope, buf_T *buf, win_T *win, Error *err)
 {
-  OptIndex opt_idx = findoption_len(name.data, name.size);
+  OptIndex opt_idx = find_option_len(name.data, name.size);
   VALIDATE_S(opt_idx != kOptInvalid, "option (not found)", name.data, {
     return (Dictionary)ARRAY_DICT_INIT;
   });
diff --git a/src/nvim/option.h b/src/nvim/option.h
index 034c3de148..44cba70302 100644
--- a/src/nvim/option.h
+++ b/src/nvim/option.h
@@ -134,7 +134,7 @@ static inline bool option_has_type(OptIndex opt_idx, OptValType type)
   // Ensure that the type is valid before accessing type_flags.
   assert(type > kOptValTypeNil && type < kOptValTypeSize);
   // Bitshift 1 by the value of type to get the type's corresponding flag, and check if it's set in
-  // the type_flags bit_field.
+  // the type_flags bit field.
   return get_option(opt_idx)->type_flags & (1 << type);
 }
 
diff --git a/src/nvim/options.lua b/src/nvim/options.lua
index 6d61a6d64e..0d5c24a793 100644
--- a/src/nvim/options.lua
+++ b/src/nvim/options.lua
@@ -2,6 +2,7 @@
 --- @field full_name string
 --- @field desc? string
 --- @field abbreviation? string
+--- @field alias? string|string[]
 --- @field short_desc? string|fun(): string
 --- @field varname? string
 --- @field pv_name? string
@@ -84,6 +85,7 @@ end
 return {
   cstr = cstr,
   --- @type vim.option_meta[]
+  --- The order of the options MUST be alphabetic for ":set all".
   options = {
     {
       abbreviation = 'al',
@@ -6809,6 +6811,7 @@ return {
     },
     {
       abbreviation = 'sd',
+      alias = { 'vi', 'viminfo' },
       cb = 'did_set_shada',
       defaults = {
         if_true = "!,'100,<50,s10,h",
@@ -6940,6 +6943,7 @@ return {
     },
     {
       abbreviation = 'sdf',
+      alias = { 'vif', 'viminfofile' },
       defaults = { if_true = '' },
       deny_duplicates = true,
       desc = [=[
@@ -9375,22 +9379,6 @@ return {
       varname = 'p_vop',
     },
     {
-      abbreviation = 'vi',
-      full_name = 'viminfo',
-      nodefault = true,
-      scope = { 'global' },
-      short_desc = N_('Alias for shada'),
-      type = 'string',
-    },
-    {
-      abbreviation = 'vif',
-      full_name = 'viminfofile',
-      nodefault = true,
-      scope = { 'global' },
-      short_desc = N_('Alias for shadafile instead'),
-      type = 'string',
-    },
-    {
       abbreviation = 've',
       cb = 'did_set_virtualedit',
       defaults = { if_true = '' },
diff --git a/src/nvim/statusline.c b/src/nvim/statusline.c
index c7d9a65b86..f4ffa2a6b8 100644
--- a/src/nvim/statusline.c
+++ b/src/nvim/statusline.c
@@ -1545,7 +1545,7 @@ int build_stl_str_hl(win_T *wp, char *out, size_t outlen, char *fmt, OptIndex op
       break;
 
     case STL_SHOWCMD:
-      if (p_sc && (opt_idx == kOptInvalid || findoption(p_sloc) == opt_idx)) {
+      if (p_sc && (opt_idx == kOptInvalid || find_option(p_sloc) == opt_idx)) {
         str = showcmd_buf;
       }
       break;