remove some wcstring -> wchar_t* -> wcstring conversions

Mostly related to usage _(L"foo"), keeping in mind the _
macro does a wcstring().c_str() already.

And a smattering of other trivial micro-optimizations certain
to not help tangibly.

src/builtin.cpp

@@ -545,8 +545,8 @@ void builtin_get_names(std::vector<completion_t> *list) {
 }
 
 /// Return a one-line description of the specified builtin.
-wcstring builtin_get_desc(const wcstring &name) {
+const wchar_t *builtin_get_desc(const wcstring &name) {
-    wcstring result;
+    const wchar_t *result;
     const builtin_data_t *builtin = builtin_lookup(name);
     if (builtin) {
         result = _(builtin->desc);

src/builtin.h

@@ -83,7 +83,7 @@ proc_status_t builtin_run(parser_t &parser, int job_pgrp, wchar_t **argv, io_str
 
 wcstring_list_t builtin_get_names();
 void builtin_get_names(std::vector<completion_t> *list);
-wcstring builtin_get_desc(const wcstring &b);
+const wchar_t *builtin_get_desc(const wcstring &b);
 
 /// Support for setting and removing transient command lines. This is used by
 /// 'complete -C' in order to make the commandline builtin operate on the string

src/builtin_argparse.cpp

@@ -448,8 +448,7 @@ static int validate_arg(parser_t &parser, const argparse_cmd_opts_t &opts, optio
     if (is_long_flag) {
         vars.set_one(var_name_prefix + L"name", ENV_LOCAL, opt_spec->long_flag);
     } else {
-        vars.set_one(var_name_prefix + L"name", ENV_LOCAL,
+        vars.set_one(var_name_prefix + L"name", ENV_LOCAL, wcstring(1, opt_spec->short_flag));
-                     wcstring(1, opt_spec->short_flag).c_str());
     }
     vars.set_one(var_name_prefix + L"value", ENV_LOCAL, woptarg);
 

src/builtin_complete.cpp

@@ -49,7 +49,7 @@ static void builtin_complete_add2(const wchar_t *cmd, int cmd_type, const wchar_
                      comp, desc, flags);
     }
 
-    if (old_opt.empty() && gnu_opt.empty() && std::wcslen(short_opt) == 0) {
+    if (old_opt.empty() && gnu_opt.empty() && short_opt[0] == L'\0') {
         complete_add(cmd, cmd_type, wcstring(), option_type_args_only, result_mode, condition, comp,
                      desc, flags);
     }

src/builtin_math.cpp

@@ -129,7 +129,7 @@ static const wchar_t *math_get_arg(int *argidx, wchar_t **argv, wcstring *storag
     return math_get_arg_argv(argidx, argv);
 }
 
-static wcstring math_describe_error(te_error_t& error) {
+static const wchar_t *math_describe_error(te_error_t& error) {
     if (error.position == 0) return L"NO ERROR?!?";
 
     switch(error.type) {
@@ -210,7 +210,7 @@ static int evaluate_expression(const wchar_t *cmd, parser_t &parser, io_streams_
             streams.out.push_back(L'\n');
         }
     } else {
-        streams.err.append_format(L"%ls: Error: %ls\n", cmd, math_describe_error(error).c_str());
+        streams.err.append_format(L"%ls: Error: %ls\n", cmd, math_describe_error(error));
         streams.err.append_format(L"'%ls'\n", expression.c_str());
         streams.err.append_format(L"%*ls%ls\n", error.position - 1, L" ",L"^");
         retval = STATUS_CMD_ERROR;

src/builtin_string.cpp

@@ -1008,13 +1008,13 @@ bool regex_replacer_t::replace_matches(const wcstring &arg) {
         }
     }
 
-    wcstring outstr(output, outlen);
     bool rc = true;
     if (pcre2_rc < 0) {
         string_error(streams, _(L"%ls: Regular expression substitute error: %ls\n"), argv0,
                      pcre2_strerror(pcre2_rc).c_str());
         rc = false;
     } else {
+        wcstring outstr(output, outlen);
         bool replacement_occurred = pcre2_rc > 0;
         if (!opts.quiet && (!opts.filter || replacement_occurred)) {
             streams.out.append(outstr);

src/common.cpp

@@ -1484,8 +1484,7 @@ static bool unescape_string_internal(const wchar_t *const input, const size_t in
                     if (unescape_special && input_position == 0 &&
                         !std::wcscmp(input, PROCESS_EXPAND_SELF_STR)) {
                         to_append_or_none = PROCESS_EXPAND_SELF;
-                        input_position +=
+                        input_position += PROCESS_EXPAND_SELF_STR_LEN - 1;  // skip over 'self's
-                            std::wcslen(PROCESS_EXPAND_SELF_STR) - 1;  // skip over 'self' part.
                     }
                     break;
                 }

src/complete.cpp

@@ -508,7 +508,7 @@ static void parse_cmd_string(const wcstring &str, wcstring *path, wcstring *cmd,
                              const environment_t &vars) {
     if (!path_get_path(str, path, vars)) {
         /// Use the empty string as the 'path' for commands that can not be found.
-        *path = L"";
+        path->clear();
     }
 
     // Make sure the path is not included in the command.
@@ -1150,8 +1150,8 @@ bool completer_t::complete_variable(const wcstring &str, size_t start_offset) {
             auto var = vars.get(env_name);
             if (!var) continue;
 
-            wcstring value = expand_escape_variable(*var);
             if (this->type() != COMPLETE_AUTOSUGGEST) {
+                wcstring value = expand_escape_variable(*var);
                 desc = format_string(COMPLETE_VAR_DESC_VAL, value.c_str());
             }
         }
@@ -1493,7 +1493,7 @@ void completer_t::perform() {
                 bool cursor_in_whitespace =
                     !plain_statement.location_in_or_at_end_of_source_range(pos);
                 if (cursor_in_whitespace) {
-                    current_argument = L"";
+                    current_argument.clear();
                     previous_argument = matching_arg;
                 } else {
                     current_argument = matching_arg;

src/env.cpp

@@ -481,7 +481,7 @@ static void update_fish_color_support(const environment_t &vars) {
         debug(2, L"256 color support enabled for TERM=%ls", term.c_str());
     } else if (term.find(L"xterm") != wcstring::npos) {
         // Assume that all 'xterm's can handle 256, except for Terminal.app from Snow Leopard
-        wcstring term_program, term_version;
+        wcstring term_program;
         if (auto tp = vars.get(L"TERM_PROGRAM")) term_program = tp->as_string();
         if (auto tpv = vars.get(L"TERM_PROGRAM_VERSION")) {
             if (term_program == L"Apple_Terminal" &&
@@ -821,7 +821,7 @@ static void handle_fish_history_change(const wcstring &op, const wcstring &var_n
                                        env_stack_t &vars) {
     UNUSED(op);
     UNUSED(var_name);
-    reader_change_history(history_session_id(vars).c_str());
+    reader_change_history(history_session_id(vars));
 }
 
 static void handle_function_path_change(const wcstring &op, const wcstring &var_name,

src/expand.h

@@ -102,6 +102,7 @@ enum expand_error_t {
 
 /// The string represented by PROCESS_EXPAND_SELF
 #define PROCESS_EXPAND_SELF_STR L"%self"
+#define PROCESS_EXPAND_SELF_STR_LEN 5
 
 /// Perform various forms of expansion on in, such as tilde expansion (\~USER becomes the users home
 /// directory), variable expansion (\$VAR_NAME becomes the value of the environment variable

src/fish_tests.cpp

@@ -2668,7 +2668,7 @@ static void test_complete() {
     do_test((completions.at(1).flags & COMPLETE_NO_SPACE) != 0);
 
     // Test wraps.
-    do_test(comma_join(complete_get_wrap_targets(L"wrapper1")) == L"");
+    do_test(comma_join(complete_get_wrap_targets(L"wrapper1")).empty());
     complete_add_wrapper(L"wrapper1", L"wrapper2");
     do_test(comma_join(complete_get_wrap_targets(L"wrapper1")) == L"wrapper2");
     complete_add_wrapper(L"wrapper2", L"wrapper3");
@@ -2679,7 +2679,7 @@ static void test_complete() {
     do_test(comma_join(complete_get_wrap_targets(L"wrapper2")) == L"wrapper3");
     do_test(comma_join(complete_get_wrap_targets(L"wrapper3")) == L"wrapper1");
     complete_remove_wrapper(L"wrapper1", L"wrapper2");
-    do_test(comma_join(complete_get_wrap_targets(L"wrapper1")) == L"");
+    do_test(comma_join(complete_get_wrap_targets(L"wrapper1")).empty());
     do_test(comma_join(complete_get_wrap_targets(L"wrapper2")) == L"wrapper3");
     do_test(comma_join(complete_get_wrap_targets(L"wrapper3")) == L"wrapper1");
 }

src/history.cpp

@@ -371,7 +371,7 @@ static size_t trim_leading_spaces(std::string &str) {
 
 static bool extract_prefix_and_unescape_yaml(std::string *key, std::string *value,
                                              const std::string &line) {
-    size_t where = line.find(":");
+    size_t where = line.find(':');
     if (where != std::string::npos) {
         key->assign(line, 0, where);
 
@@ -1868,7 +1868,7 @@ wcstring history_session_id(const environment_t &vars) {
     if (var) {
         wcstring session_id = var->as_string();
         if (session_id.empty()) {
-            result = L"";
+            result.clear();
         } else if (session_id == L"default") {
             ;  // using the default value
         } else if (valid_var_name(session_id)) {

src/output.cpp

@@ -234,7 +234,7 @@ void outputter_t::set_color(rgb_color_t c, rgb_color_t c2) {
         if (c == c2) c = (c2 == rgb_color_t::white()) ? rgb_color_t::black() : rgb_color_t::white();
     }
 
-    if ((enter_bold_mode != 0) && (std::strlen(enter_bold_mode) > 0)) {
+    if (enter_bold_mode && enter_bold_mode[0] != '\0') {
         if (bg_set && !last_bg_set) {
             // Background color changed and is set, so we enter bold mode to make reading easier.
             // This means bold mode is _always_ on when the background color is set.
@@ -295,7 +295,7 @@ void outputter_t::set_color(rgb_color_t c, rgb_color_t c2) {
     }
 
     // Lastly, we set bold, underline, italics, dim, and reverse modes correctly.
-    if (is_bold && !was_bold && enter_bold_mode && std::strlen(enter_bold_mode) > 0 && !bg_set) {
+    if (is_bold && !was_bold && enter_bold_mode && enter_bold_mode[0] != '\0' && !bg_set) {
         // The unconst cast is for NetBSD's benefit. DO NOT REMOVE!
         writembs_nofail(*this, tparm((char *)enter_bold_mode));
         was_bold = is_bold;
@@ -310,27 +310,27 @@ void outputter_t::set_color(rgb_color_t c, rgb_color_t c2) {
     }
     was_underline = is_underline;
 
-    if (was_italics && !is_italics && enter_italics_mode && std::strlen(enter_italics_mode) > 0) {
+    if (was_italics && !is_italics && enter_italics_mode && enter_italics_mode[0] != '\0') {
         writembs_nofail(*this, exit_italics_mode);
         was_italics = is_italics;
     }
 
-    if (!was_italics && is_italics && enter_italics_mode && std::strlen(enter_italics_mode) > 0) {
+    if (!was_italics && is_italics && enter_italics_mode && enter_italics_mode[0] != '\0') {
         writembs_nofail(*this, enter_italics_mode);
         was_italics = is_italics;
     }
 
-    if (is_dim && !was_dim && enter_dim_mode && std::strlen(enter_dim_mode) > 0) {
+    if (is_dim && !was_dim && enter_dim_mode && enter_dim_mode[0] != '\0') {
         writembs_nofail(*this, enter_dim_mode);
         was_dim = is_dim;
     }
 
     if (is_reverse && !was_reverse) {
         // Some terms do not have a reverse mode set, so standout mode is a fallback.
-        if (enter_reverse_mode && std::strlen(enter_reverse_mode) > 0) {
+        if (enter_reverse_mode && enter_reverse_mode[0] != '\0') {
             writembs_nofail(*this, enter_reverse_mode);
             was_reverse = is_reverse;
-        } else if (enter_standout_mode && std::strlen(enter_standout_mode) > 0) {
+        } else if (enter_standout_mode && enter_standout_mode[0] != '\0') {
             writembs_nofail(*this, enter_standout_mode);
             was_reverse = is_reverse;
         }

src/parse_tree.cpp

@@ -691,7 +691,7 @@ void parse_ll_t::report_tokenizer_error(const tok_t &tok) {
     parse_error_code_t parse_error_code = parse_error_from_tokenizer_error(tok.error);
     this->parse_error_at_location(tok.offset, tok.length, tok.offset + tok.error_offset,
                                   parse_error_code, L"%ls",
-                                  tokenizer_get_error_message(tok.error).c_str());
+                                  tokenizer_get_error_message(tok.error));
 }
 
 void parse_ll_t::parse_error_unexpected_token(const wchar_t *expected, parse_token_t token) {

src/tokenizer.cpp

@@ -17,7 +17,8 @@
 #include "tokenizer.h"
 #include "wutil.h"  // IWYU pragma: keep
 
-wcstring tokenizer_get_error_message(tokenizer_error_t err) {
+// _(s) is already wgettext(s).c_str(), so let's not convert back to wcstring
+const wchar_t * tokenizer_get_error_message(tokenizer_error_t err) {
     switch (err) {
         case tokenizer_error_t::none:
             return L"";
@@ -47,7 +48,7 @@ wcstring tokenizer_get_error_message(tokenizer_error_t err) {
             return _(L"Unexpected ')' found, expecting '}'");
     }
     assert(0 && "Unexpected tokenizer error");
-    return NULL;
+    return nullptr;
 }
 
 // Whether carets redirect stderr.

src/tokenizer.h

@@ -61,7 +61,7 @@ enum class tokenizer_error_t {
 };
 
 /// Get the error message for an error \p err.
-wcstring tokenizer_get_error_message(tokenizer_error_t err);
+const wchar_t *tokenizer_get_error_message(tokenizer_error_t err);
 
 struct tok_t {
     // The type of the token.

src/wildcard.cpp

@@ -336,7 +336,7 @@ bool wildcard_match(const wcstring &str, const wcstring &wc, bool leading_dots_f
 /// \param stat_res The result of calling stat on the file
 /// \param buf The struct buf output of calling stat on the file
 /// \param err The errno value after a failed stat call on the file.
-static wcstring file_get_desc(const wcstring &filename, int lstat_res, const struct stat &lbuf,
+static const wchar_t *file_get_desc(const wcstring &filename, int lstat_res, const struct stat &lbuf,
                               int stat_res, const struct stat &buf, int err) {
     if (lstat_res) {
         return COMPLETE_FILE_DESC;
@@ -929,14 +929,12 @@ int wildcard_expand_string(const wcstring &wc, const wcstring &working_directory
     // Check for a leading slash. If we find one, we have an absolute path: the prefix is empty, the
     // base dir is /, and the wildcard is the remainder. If we don't find one, the prefix is the
     // working directory, the base dir is empty.
-    wcstring prefix, base_dir, effective_wc;
+    wcstring prefix = L"", base_dir = L"", effective_wc;
     if (string_prefixes_string(L"/", wc)) {
-        prefix = L"";
         base_dir = L"/";
         effective_wc = wc.substr(1);
     } else {
         prefix = working_directory;
-        base_dir = L"";
         effective_wc = wc;
     }
 

src/wutil.cpp

@@ -39,7 +39,7 @@ static owning_lock<std::unordered_map<wcstring, wcstring>> wgettext_map;
 bool wreaddir_resolving(DIR *dir, const wcstring &dir_path, wcstring &out_name, bool *out_is_dir) {
     struct dirent *result = readdir(dir);
     if (!result) {
-        out_name = L"";
+        out_name.clear();
         return false;
     }
 
@@ -85,7 +85,7 @@ bool wreaddir_resolving(DIR *dir, const wcstring &dir_path, wcstring &out_name,
 bool wreaddir(DIR *dir, wcstring &out_name) {
     struct dirent *result = readdir(dir);
     if (!result) {
-        out_name = L"";
+        out_name.clear();
         return false;
     }