add option to modify script being restyled

This change allows the user to specify the script name on the CLI in addition
to being redirected from stdin. It also adds a `-w` flag to write the modified
script to the original file.

doc_src/fish_indent.txt

@@ -7,12 +7,14 @@ fish_indent [OPTIONS]
 
 \subsection fish_indent-description Description
 
-`fish_indent` is used to indent a piece of fish code. `fish_indent` reads commands from standard input and outputs them to standard output.
+`fish_indent` is used to indent a piece of fish code. `fish_indent` reads commands from standard input and outputs them to standard output or a specified file.
 
 The following options are available:
 
 - `-d` or `--dump` dumps information about the parsed fish commands to stderr
 
+- `-w` or `--write` indents a specified file and immediately writes to that file
+
 - `-i` or `--no-indent` do not indent commands; only reformat to one job per line
 
 - `-v` or `--version` displays the current fish version and then exits

src/fish_indent.cpp

@@ -18,12 +18,14 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 #include "config.h"  // IWYU pragma: keep
 
 #include <assert.h>
+#include <errno.h>
 #include <getopt.h>
 #include <locale.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <wchar.h>
 #include <wctype.h>
 #include <memory>
@@ -164,10 +166,9 @@ static void prettify_node_recursive(const wcstring &source, const parse_node_tre
 // Entry point for prettification.
 static wcstring prettify(const wcstring &src, bool do_indent) {
     parse_node_tree_t tree;
-    if (!parse_tree_from_string(src,
+    int parse_flags = (parse_flag_continue_after_error | parse_flag_include_comments |
-                                parse_flag_continue_after_error | parse_flag_include_comments |
+                       parse_flag_leave_unterminated | parse_flag_show_blank_lines);
-                                    parse_flag_leave_unterminated | parse_flag_show_blank_lines,
+    if (!parse_tree_from_string(src, parse_flags, &tree, NULL)) {
-                                &tree, NULL /* errors */)) {
         // We return the initial string on failure.
         return src;
     }
@@ -339,26 +340,27 @@ int main(int argc, char *argv[]) {
     // Types of output we support.
     enum {
         output_type_plain_text,
+        output_type_file,
         output_type_ansi,
         output_type_html
     } output_type = output_type_plain_text;
+    const char *output_location;
     bool do_indent = true;
 
-    const char *short_opts = "+dhvi";
+    const char *short_opts = "+dhvwi";
-    const struct option long_opts[] = {{"dump", no_argument, NULL, 'd'},
+    const struct option long_opts[] = {
-                                       {"no-indent", no_argument, NULL, 'i'},
+        {"dump", no_argument, NULL, 'd'},  {"no-indent", no_argument, NULL, 'i'},
-                                       {"help", no_argument, NULL, 'h'},
+        {"help", no_argument, NULL, 'h'},  {"version", no_argument, NULL, 'v'},
-                                       {"version", no_argument, NULL, 'v'},
+        {"write", no_argument, NULL, 'w'}, {"html", no_argument, NULL, 1},
-                                       {"html", no_argument, NULL, 1},
+        {"ansi", no_argument, NULL, 2},    {NULL, 0, NULL, 0}};
-                                       {"ansi", no_argument, NULL, 2},
-                                       {NULL, 0, NULL, 0}};
 
     int opt;
     while ((opt = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
         switch (opt) {
             case 0: {
                 fwprintf(stderr, _(L"getopt_long() unexpectedly returned zero\n"));
-                exit_without_destructors(127);
+                exit(127);
+                break;
             }
             case 'd': {
                 dump_parse_tree = true;
@@ -366,12 +368,16 @@ int main(int argc, char *argv[]) {
             }
             case 'h': {
                 print_help("fish_indent", 1);
-                exit_without_destructors(0);
+                exit(0);
+                break;
             }
             case 'v': {
                 fwprintf(stderr, _(L"%ls, version %s\n"), program_name, get_fish_version());
                 exit(0);
-                assert(0 && "Unreachable code reached");
+                break;
+            }
+            case 'w': {
+                output_type = output_type_file;
                 break;
             }
             case 'i': {
@@ -388,12 +394,33 @@ int main(int argc, char *argv[]) {
             }
             default: {
                 // We assume getopt_long() has already emitted a diagnostic msg.
-                exit_without_destructors(1);
+                exit(1);
+                break;
             }
         }
     }
 
-    const wcstring src = read_file(stdin);
+    argc -= optind;
+    argv += optind;
+
+    wcstring src;
+    if (argc == 0) {
+        src = read_file(stdin);
+    } else if (argc == 1) {
+        FILE *fh = fopen(*argv, "r");
+        if (fh) {
+            src = read_file(fh);
+            fclose(fh);
+            output_location = *argv;
+        } else {
+            fwprintf(stderr, _(L"Opening \"%s\" failed: %s\n"), *argv, strerror(errno));
+            exit(1);
+        }
+    } else {
+        fwprintf(stderr, _(L"Too many arguments\n"));
+        exit(1);
+    }
+
     const wcstring output_wtext = prettify(src, do_indent);
 
     // Maybe colorize.
@@ -409,6 +436,19 @@ int main(int argc, char *argv[]) {
             colored_output = no_colorize(output_wtext);
             break;
         }
+        case output_type_file: {
+            FILE *fh = fopen(output_location, "w");
+            if (fh) {
+                fputs(wcs2str(output_wtext), fh);
+                fclose(fh);
+                exit(0);
+            } else {
+                fwprintf(stderr, _(L"Opening \"%s\" failed: %s\n"), output_location,
+                         strerror(errno));
+                exit(1);
+            }
+            break;
+        }
         case output_type_ansi: {
             colored_output = ansi_colorize(output_wtext, colors);
             break;