Support reading file from standard input

Fixes quick-lint#263
Updates quick-lint#275

Signed-off-by: wagner riffel <[email protected]>

Author: wgrr

src/file.cpp

@@ -211,6 +211,11 @@ read_file_result read_file(const char *path) {
   windows_handle_file file(handle);
   return read_file(path, file.ref());
 }
+
+read_file_result read_stdin() {
+  windows_handle_file file(::GetStdHandle(STD_INPUT_HANDLE));
+  return read_file("<stdin>", file.ref());
+}
 #endif
 
 #if defined(QLJS_FILE_POSIX)
@@ -224,6 +229,11 @@ read_file_result read_file(const char *path) {
   posix_fd_file file(fd);
   return read_file(path, file.ref());
 }
+
+read_file_result read_stdin() {
+  posix_fd_file file(STDIN_FILENO);
+  return read_file("<stdin>", file.ref());
+}
 #endif
 
 void write_file(const std::string &path, string8_view content) {

src/main.cpp

@@ -150,13 +150,20 @@ void handle_options(quick_lint_js::options o) {
     quick_lint_js::run_lsp_server();
     std::exit(EXIT_SUCCESS);
   }
-  if (o.files_to_lint.empty()) {
+  if (o.files_to_lint.empty() && !o.stdin) {
     std::cerr << "error: expected file name\n";
     std::exit(EXIT_FAILURE);
   }
 
   quick_lint_js::any_error_reporter reporter =
       quick_lint_js::any_error_reporter::make(o.output_format, &o.exit_fail_on);
+  if (o.stdin) {
+    quick_lint_js::read_file_result source = quick_lint_js::read_stdin();
+    file_to_lint fstdin{.path = "<stdin>", .vim_bufnr = std::nullopt};
+    reporter.set_source(&source.content, fstdin);
+    quick_lint_js::process_file(&source.content, reporter.get(),
+                                o.print_parser_visits);
+  }
   for (const quick_lint_js::file_to_lint &file : o.files_to_lint) {
     quick_lint_js::read_file_result source =
         quick_lint_js::read_file(file.path);
@@ -394,6 +401,7 @@ void print_help_message() {
   print_option("--exit-fail-on=[CODES]",
                "Fail with a non-zero exit code if any of these");
   print_option("", "errors are found (default: \"all\")");
+  print_option("--s, --stdin", "Read standard input as a javascript file");
   print_option("--lsp, --lsp-server",
                "Run in Language Server mode (for LSP-aware editors)");
   print_option("--output-format=[FORMAT]",

src/options.cpp

@@ -99,6 +99,10 @@ class arg_parser {
       this->is_ignoring_options_ = true;
       this->option_ = std::nullopt;
     } else if (this->current_arg()[0] == '-') {
+      if (std::strcmp(this->current_arg(), "-") == 0) {
+        this->option_ = std::nullopt;
+        return;
+      }
       const char* equal = std::strchr(this->current_arg(), '=');
       option o;
       o.arg_has_equal = equal != nullptr;
@@ -152,6 +156,10 @@ options parse_options(int argc, char** argv) {
   arg_parser parser(argc, argv);
   while (!parser.done()) {
     if (const char* argument = parser.match_argument()) {
+      if (std::strcmp(argument, "-") == 0) {
+        o.stdin = true;
+        continue;
+      }
       file_to_lint file{.path = argument, .vim_bufnr = next_vim_file_bufnr};
       o.files_to_lint.emplace_back(file);
       next_vim_file_bufnr = std::nullopt;
@@ -188,6 +196,8 @@ options parse_options(int argc, char** argv) {
       o.version = true;
     } else if (parser.match_flag_option("--lsp-server"sv, "--lsp"sv)) {
       o.lsp_server = true;
+    } else if (parser.match_flag_option("--stdin"sv, "--s"sv)) {
+      o.stdin = true;
     } else {
       const char* unrecognized = parser.match_anything();
       o.error_unrecognized_options.emplace_back(unrecognized);

src/quick-lint-js/file.h

@@ -24,6 +24,8 @@ read_file_result read_file(const char *path);
 
 read_file_result read_file(const char *path, platform_file_ref);
 
+read_file_result read_stdin(void);
+
 void write_file(const std::string &path, string8_view content);
 void write_file(const char *path, string8_view content);
 }

src/quick-lint-js/options.h

@@ -26,6 +26,7 @@ struct options {
   bool version = false;
   bool print_parser_visits = false;
   bool lsp_server = false;
+  bool stdin = false;
   quick_lint_js::output_format output_format =
       quick_lint_js::output_format::default_format;
   std::vector<file_to_lint> files_to_lint;

test/test-options.cpp

@@ -35,6 +35,7 @@ TEST(test_options, default_options_with_no_files) {
   EXPECT_FALSE(o.help);
   EXPECT_FALSE(o.version);
   EXPECT_FALSE(o.lsp_server);
+  EXPECT_FALSE(o.stdin);
   EXPECT_EQ(o.output_format, output_format::default_format);
   EXPECT_THAT(o.files_to_lint, IsEmpty());
 }
@@ -176,6 +177,25 @@ TEST(test_options, lsp_server) {
   }
 }
 
+TEST(test_options, stdin) {
+  {
+    options o = parse_options({"--stdin"});
+    EXPECT_TRUE(o.stdin);
+  }
+  {
+    options o = parse_options({"--s"});
+    EXPECT_TRUE(o.stdin);
+  }
+}
+
+TEST(test_options, single_hypen_is_argument) {
+  {
+    options o = parse_options({"one.js", "-", "two.js"});
+    ASSERT_EQ(o.files_to_lint.size(), 2);
+    EXPECT_TRUE(o.stdin);
+  }
+}
+
 TEST(test_options, print_help) {
   {
     options o = parse_options({"--help"});