Capture read command contents without displaying it via a silent flag.

Implement a `read --silent` flag. This echos the input using an
obfuscation character.

src/builtin.cpp

@@ -1976,9 +1976,9 @@ static int builtin_random(parser_t &parser, io_streams_t &streams, wchar_t **arg
 
 /// Read from the tty. This is only valid when the stream is stdin and it is attached to a tty and
 /// we weren't asked to split on null characters.
-static int read_interactive(wcstring &buff, int nchars, bool shell, const wchar_t *mode_name,
-                            const wchar_t *prompt, const wchar_t *right_prompt,
-                            const wchar_t *commandline) {
+static int read_interactive(wcstring &buff, int nchars, bool shell, bool silent,
+                            const wchar_t *mode_name, const wchar_t *prompt,
+                            const wchar_t *right_prompt, const wchar_t *commandline) {
     int exit_res = STATUS_BUILTIN_OK;
     const wchar_t *line;
 
@@ -1994,6 +1994,7 @@ static int read_interactive(wcstring &buff, int nchars, bool shell, const wchar_
     reader_set_allow_autosuggesting(false);
     reader_set_expand_abbreviations(false);
     reader_set_exit_on_interrupt(true);
+    reader_set_silent_status(silent);
 
     reader_set_buffer(commandline, wcslen(commandline));
     proc_push_interactive(1);
@@ -2137,9 +2138,10 @@ static int builtin_read(parser_t &parser, io_streams_t &streams, wchar_t **argv)
     int nchars = 0;
     bool shell = false;
     bool array = false;
+    bool silent = false;
     bool split_null = false;
 
-    const wchar_t *short_options = L"ac:ghlm:n:p:suxzP:UR:";
+    const wchar_t *short_options = L"ac:ghilm:n:p:suxzP:UR:";
     const struct woption long_options[] = {{L"export", no_argument, NULL, 'x'},
                                            {L"global", no_argument, NULL, 'g'},
                                            {L"local", no_argument, NULL, 'l'},
@@ -2150,6 +2152,7 @@ static int builtin_read(parser_t &parser, io_streams_t &streams, wchar_t **argv)
                                            {L"right-prompt", required_argument, NULL, 'R'},
                                            {L"command", required_argument, NULL, 'c'},
                                            {L"mode-name", required_argument, NULL, 'm'},
+                                           {L"silent", no_argument, NULL, 'i'},
                                            {L"nchars", required_argument, NULL, 'n'},
                                            {L"shell", no_argument, NULL, 's'},
                                            {L"array", no_argument, NULL, 'a'},
@@ -2226,6 +2229,10 @@ static int builtin_read(parser_t &parser, io_streams_t &streams, wchar_t **argv)
                 array = true;
                 break;
             }
+            case L'i': {
+                silent = true;
+                break;
+            }
             case L'z': {
                 split_null = true;
                 break;
@@ -2302,8 +2309,8 @@ static int builtin_read(parser_t &parser, io_streams_t &streams, wchar_t **argv)
         // We should read interactively using reader_readline(). This does not support splitting on
         // null. The call to reader_readline may change woptind, so we save and restore it.
         int saved_woptind = w.woptind;
-        exit_res =
-            read_interactive(buff, nchars, shell, mode_name, prompt, right_prompt, commandline);
+        exit_res = read_interactive(buff, nchars, shell, silent, mode_name, prompt, right_prompt,
+                                    commandline);
         w.woptind = saved_woptind;
     } else if (!nchars && !stream_stdin_is_a_tty && lseek(streams.stdin_fd, 0, SEEK_CUR) != -1) {
         exit_res = read_in_chunks(streams.stdin_fd, buff, split_null);

src/common.cpp

@@ -50,6 +50,7 @@ static bool thread_asserts_cfg_for_testing = false;
 
 wchar_t ellipsis_char;
 wchar_t omitted_newline_char;
+wchar_t obfuscation_read_char;
 bool g_profiling_active = false;
 const wchar_t *program_name;
 int debug_level = 1;         // default maximum debug output level (errors and warnings)
@@ -457,6 +458,9 @@ void fish_setlocale() {
 
     // Use the Unicode "return" symbol if it can be encoded using the current locale.
     omitted_newline_char = can_be_encoded(L'\x23CE') ? L'\x23CE' : L'~';
+
+    // solid circle unicode character if it is able, fallback to the hash character
+    obfuscation_read_char = can_be_encoded(L'\u25cf') ? L'\u25cf' : L'#';
 }
 
 long read_blocked(int fd, void *buf, size_t count) {

src/common.h

@@ -159,6 +159,9 @@ extern wchar_t ellipsis_char;
 /// Character representing an omitted newline at the end of text.
 extern wchar_t omitted_newline_char;
 
+/// Character used for the silent mode of the read command
+extern wchar_t obfuscation_read_char;
+
 /// The verbosity level of fish. If a call to debug has a severity level higher than \c debug_level,
 /// it will not be printed.
 extern int debug_level;

src/reader.cpp

@@ -168,6 +168,8 @@ class reader_data_t {
     bool suppress_autosuggestion;
     /// Whether abbreviations are expanded.
     bool expand_abbreviations;
+    /// Silent mode used for password input on the read command
+    bool silent;
     /// The representation of the current screen contents.
     screen_t screen;
     /// The history.
@@ -256,13 +258,14 @@ class reader_data_t {
 
     /// Constructor
     reader_data_t()
-        : allow_autosuggestion(0),
-          suppress_autosuggestion(0),
-          expand_abbreviations(0),
+        : allow_autosuggestion(false),
+          suppress_autosuggestion(false),
+          expand_abbreviations(false),
+          silent(false),
           history(0),
           token_history_pos(0),
           search_pos(0),
-          sel_active(0),
+          sel_active(false),
           sel_begin_pos(0),
           sel_start_pos(0),
           sel_stop_pos(0),
@@ -270,13 +273,13 @@ class reader_data_t {
           complete_func(0),
           highlight_function(0),
           test_func(0),
-          end_loop(0),
-          prev_end_loop(0),
+          end_loop(false),
+          prev_end_loop(false),
           next(0),
           search_mode(0),
-          repaint_needed(0),
-          screen_reset_needed(0),
-          exit_on_interrupt(0) {}
+          repaint_needed(false),
+          screen_reset_needed(false),
+          exit_on_interrupt(false) {}
 };
 
 /// Sets the command line contents, without clearing the pager.
@@ -412,8 +415,13 @@ static void reader_repaint() {
     // Update the indentation.
     data->indents = parse_util_compute_indents(cmd_line->text);
 
-    // Combine the command and autosuggestion into one string.
-    wcstring full_line = combine_command_and_autosuggestion(cmd_line->text, data->autosuggestion);
+    wcstring full_line;
+    if (data->silent) {
+        full_line = wcstring(cmd_line->text.length(), obfuscation_read_char);
+    } else {
+        // Combine the command and autosuggestion into one string.
+        full_line = combine_command_and_autosuggestion(cmd_line->text, data->autosuggestion);
+    }
 
     size_t len = full_line.size();
     if (len < 1) len = 1;
@@ -439,9 +447,9 @@ static void reader_repaint() {
     bool focused_on_pager = data->active_edit_line() == &data->pager.search_field_line;
     size_t cursor_position = focused_on_pager ? data->pager.cursor_position() : cmd_line->position;
 
-    s_write(&data->screen, data->left_prompt_buff, data->right_prompt_buff, full_line,
-            cmd_line->size(), &colors[0], &indents[0], cursor_position,
-            data->current_page_rendering, focused_on_pager);
+    s_write(&data->screen, data->left_prompt_buff, data->right_prompt_buff, full_line, cmd_line->size(),
+            &colors[0], &indents[0], cursor_position, data->current_page_rendering,
+            focused_on_pager);
 
     data->repaint_needed = false;
 }
@@ -2044,6 +2052,8 @@ void reader_set_test_function(parser_test_error_bits_t (*f)(const wchar_t *)) {
 
 void reader_set_exit_on_interrupt(bool i) { data->exit_on_interrupt = i; }
 
+void reader_set_silent_status(bool flag) { data->silent = flag; }
+
 void reader_import_history_if_necessary(void) {
     // Import history from older location (config path) if our current history is empty.
     if (data->history && data->history->is_empty()) {

src/reader.h

@@ -189,6 +189,8 @@ void reader_set_expand_abbreviations(bool flag);
 /// Sets whether the reader should exit on ^C.
 void reader_set_exit_on_interrupt(bool flag);
 
+void reader_set_silent_status(bool f);
+
 /// Returns true if the shell is exiting, 0 otherwise.
 bool shell_is_exiting();
 

tests/read.expect

@@ -36,6 +36,15 @@ expect_prompt
 expect_marker 2
 print_var_contents foo
 
+# read -i
+
+send_line "read -i foo"
+expect_read_prompt
+send_line -h "read_i\r_marker 3"
+expect_prompt
+expect_marker 3
+print_var_contents foo
+
 # read -n
 
 send_line "read -n 3 foo"

tests/read.expect.out

@@ -1,6 +1,7 @@
 $foo: 'text'
 $foo: 'again'
 $foo: 'bar'
+$foo: 'read_i'
 $foo: '123'
 $foo: '456'
 $foo: 'hello'