Merge pull request #148 from mitchellh/prompt-redraw

Semantic Prompt Redraw

src/terminal/Screen.zig

@@ -2027,6 +2027,7 @@ pub fn resize(self: *Screen, rows: usize, cols: usize) !void {
                         try self.scroll(.{ .delta = 1 });
                     }
                     new_row = self.getRow(.{ .active = y });
+                    new_row.setSemanticPrompt(old_row.getSemanticPrompt());
                 }
             }
         }
@@ -2112,6 +2113,8 @@ pub fn resize(self: *Screen, rows: usize, cols: usize) !void {
                 }
 
                 const row = self.getRow(.{ .active = y });
+                row.setSemanticPrompt(old_row.getSemanticPrompt());
+
                 fastmem.copy(
                     StorageCell,
                     row.storage[1..],
@@ -2125,6 +2128,7 @@ pub fn resize(self: *Screen, rows: usize, cols: usize) !void {
             // Slow path: the row is wrapped or doesn't fit so we have to
             // wrap ourselves. In this case, we basically just "print and wrap"
             var row = self.getRow(.{ .active = y });
+            row.setSemanticPrompt(old_row.getSemanticPrompt());
             var x: usize = 0;
             var cur_old_row = old_row;
             var cur_old_row_wrapped = old_row_wrapped;
@@ -2145,6 +2149,7 @@ pub fn resize(self: *Screen, rows: usize, cols: usize) !void {
                         }
 
                         row = self.getRow(.{ .active = y });
+                        row.setSemanticPrompt(cur_old_row.getSemanticPrompt());
                     }
 
                     // If our cursor is on this char, then set the new cursor.
@@ -4450,6 +4455,53 @@ test "Screen: resize more cols trailing background colors" {
     }
 }
 
+test "Screen: resize more cols no reflow preserves semantic prompt" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    var s = try init(alloc, 3, 5, 0);
+    defer s.deinit();
+    const str = "1ABCD\n2EFGH\n3IJKL";
+    try s.testWriteString(str);
+
+    // Set one of the rows to be a prompt
+    {
+        const row = s.getRow(.{ .active = 1 });
+        row.setSemanticPrompt(.prompt);
+    }
+
+    const cursor = s.cursor;
+    try s.resize(3, 10);
+
+    // Cursor should not move
+    try testing.expectEqual(cursor, s.cursor);
+
+    {
+        var contents = try s.testString(alloc, .viewport);
+        defer alloc.free(contents);
+        try testing.expectEqualStrings(str, contents);
+    }
+    {
+        var contents = try s.testString(alloc, .screen);
+        defer alloc.free(contents);
+        try testing.expectEqualStrings(str, contents);
+    }
+
+    // Our one row should still be a semantic prompt, the others should not.
+    {
+        const row = s.getRow(.{ .active = 0 });
+        try testing.expect(row.getSemanticPrompt() == .unknown);
+    }
+    {
+        const row = s.getRow(.{ .active = 1 });
+        try testing.expect(row.getSemanticPrompt() == .prompt);
+    }
+    {
+        const row = s.getRow(.{ .active = 2 });
+        try testing.expect(row.getSemanticPrompt() == .unknown);
+    }
+}
+
 test "Screen: resize more cols grapheme map" {
     const testing = std.testing;
     const alloc = testing.allocator;
@@ -4973,6 +5025,55 @@ test "Screen: resize less cols with graphemes" {
     }
 }
 
+test "Screen: resize less cols no reflow preserves semantic prompt" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    var s = try init(alloc, 3, 5, 0);
+    defer s.deinit();
+    const str = "1AB\n2EF\n3IJ";
+    try s.testWriteString(str);
+
+    // Set one of the rows to be a prompt
+    {
+        const row = s.getRow(.{ .active = 1 });
+        row.setSemanticPrompt(.prompt);
+    }
+
+    s.cursor.x = 0;
+    s.cursor.y = 0;
+    const cursor = s.cursor;
+    try s.resize(3, 3);
+
+    // Cursor should not move
+    try testing.expectEqual(cursor, s.cursor);
+
+    {
+        var contents = try s.testString(alloc, .viewport);
+        defer alloc.free(contents);
+        try testing.expectEqualStrings(str, contents);
+    }
+    {
+        var contents = try s.testString(alloc, .screen);
+        defer alloc.free(contents);
+        try testing.expectEqualStrings(str, contents);
+    }
+
+    // Our one row should still be a semantic prompt, the others should not.
+    {
+        const row = s.getRow(.{ .active = 0 });
+        try testing.expect(row.getSemanticPrompt() == .unknown);
+    }
+    {
+        const row = s.getRow(.{ .active = 1 });
+        try testing.expect(row.getSemanticPrompt() == .prompt);
+    }
+    {
+        const row = s.getRow(.{ .active = 2 });
+        try testing.expect(row.getSemanticPrompt() == .unknown);
+    }
+}
+
 test "Screen: resize less cols with reflow but row space" {
     const testing = std.testing;
     const alloc = testing.allocator;

src/terminal/Terminal.zig

@@ -94,6 +94,12 @@ modes: packed struct {
 
     bracketed_paste: bool = false, // 2004
 
+    // This isn't a mode, this is set by OSC 133 using the "A" event.
+    // If this is true, it tells us that the shell supports redrawing
+    // the prompt and that when we resize, if the cursor is at a prompt,
+    // then we should clear the screen below and allow the shell to redraw.
+    shell_redraws_prompt: bool = false,
+
     test {
         // We have this here so that we explicitly fail when we change the
         // size of modes. The size of modes is NOT particularly important,
@@ -312,6 +318,7 @@ pub fn resize(self: *Terminal, alloc: Allocator, cols_req: usize, rows: usize) !
 
     // If we're making the screen smaller, dealloc the unused items.
     if (self.active_screen == .primary) {
+        self.clearPromptForResize();
         try self.screen.resize(rows, cols);
         try self.secondary_screen.resizeWithoutReflow(rows, cols);
     } else {
@@ -330,6 +337,58 @@ pub fn resize(self: *Terminal, alloc: Allocator, cols_req: usize, rows: usize) !
     };
 }
 
+/// If modes.shell_redraws_prompt is true and we're on the primary screen,
+/// then this will clear the screen from the cursor down if the cursor is
+/// on a prompt in order to allow the shell to redraw the prompt.
+fn clearPromptForResize(self: *Terminal) void {
+    assert(self.active_screen == .primary);
+
+    if (!self.modes.shell_redraws_prompt) return;
+
+    // We need to find the first y that is a prompt. If we find any line
+    // that is NOT a prompt (or input -- which is part of a prompt) then
+    // we are not at a prompt and we can exit this function.
+    const prompt_y: usize = prompt_y: {
+        // Keep track of the found value, because we want to find the START
+        var found: ?usize = null;
+
+        // Search from the cursor up
+        var y: usize = 0;
+        while (y <= self.screen.cursor.y) : (y += 1) {
+            const real_y = self.screen.cursor.y - y;
+            const row = self.screen.getRow(.{ .active = real_y });
+            switch (row.getSemanticPrompt()) {
+                // If we're at a prompt or input area, then we are at a prompt.
+                // We mark our found value and continue because the prompt
+                // may be multi-line.
+                .prompt,
+                .input,
+                => found = real_y,
+
+                // If we have command output, then we're most certainly not
+                // at a prompt. Break out of the loop.
+                .command => break,
+
+                // If we don't know, we keep searching.
+                .unknown => {},
+            }
+        }
+
+        if (found) |found_y| break :prompt_y found_y;
+        return;
+    };
+    assert(prompt_y < self.rows);
+
+    // We want to clear all the lines from prompt_y downwards because
+    // the shell will redraw the prompt.
+    for (prompt_y..self.rows) |y| {
+        const row = self.screen.getRow(.{ .active = y });
+        row.setWrapped(false);
+        row.setDirty(true);
+        row.clear(.{});
+    }
+}
+
 /// Return the current string value of the terminal. Newlines are
 /// encoded as "\n". This omits any formatting such as fg/bg.
 ///

src/terminal/osc.zig

@@ -26,6 +26,7 @@ pub const Command = union(enum) {
     /// not all shells will send the prompt end code.
     prompt_start: struct {
         aid: ?[]const u8 = null,
+        redraw: bool = true,
     },
 
     /// End of prompt and start of user input, terminated by a OSC "133;C"
@@ -345,6 +346,29 @@ pub const Parser = struct {
                 .prompt_start => |*v| v.aid = value,
                 else => {},
             }
+        } else if (mem.eql(u8, self.temp_state.key, "redraw")) {
+            // Kitty supports a "redraw" option for prompt_start. I can't find
+            // this documented anywhere but can see in the code that this is used
+            // by shell environments to tell the terminal that the shell will NOT
+            // redraw the prompt so we should attempt to resize it.
+            switch (self.command) {
+                .prompt_start => |*v| {
+                    const valid = if (value.len == 1) valid: {
+                        switch (value[0]) {
+                            '0' => v.redraw = false,
+                            '1' => v.redraw = true,
+                            else => break :valid false,
+                        }
+
+                        break :valid true;
+                    } else false;
+
+                    if (!valid) {
+                        log.info("OSC 133 A invalid redraw value: {s}", .{value});
+                    }
+                },
+                else => {},
+            }
         } else log.info("unknown semantic prompts option: {s}", .{self.temp_state.key});
     }
 
@@ -416,6 +440,7 @@ test "OSC: prompt_start" {
     const cmd = p.end().?;
     try testing.expect(cmd == .prompt_start);
     try testing.expect(cmd.prompt_start.aid == null);
+    try testing.expect(cmd.prompt_start.redraw);
 }
 
 test "OSC: prompt_start with single option" {
@@ -431,6 +456,32 @@ test "OSC: prompt_start with single option" {
     try testing.expectEqualStrings("14", cmd.prompt_start.aid.?);
 }
 
+test "OSC: prompt_start with redraw disabled" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "133;A;redraw=0";
+    for (input) |ch| p.next(ch);
+
+    const cmd = p.end().?;
+    try testing.expect(cmd == .prompt_start);
+    try testing.expect(!cmd.prompt_start.redraw);
+}
+
+test "OSC: prompt_start with redraw invalid value" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "133;A;redraw=42";
+    for (input) |ch| p.next(ch);
+
+    const cmd = p.end().?;
+    try testing.expect(cmd == .prompt_start);
+    try testing.expect(cmd.prompt_start.redraw);
+}
+
 test "OSC: end_of_command no exit code" {
     const testing = std.testing;
 

src/terminal/stream.zig

@@ -471,9 +471,9 @@ pub fn Stream(comptime Handler: type) type {
                     } else log.warn("unimplemented OSC callback: {}", .{cmd});
                 },
 
-                .prompt_start => {
+                .prompt_start => |v| {
                     if (@hasDecl(T, "promptStart")) {
-                        try self.handler.promptStart();
+                        try self.handler.promptStart(v.aid, v.redraw);
                     } else log.warn("unimplemented OSC callback: {}", .{cmd});
                 },
 

src/termio/Exec.zig

@@ -1236,8 +1236,10 @@ const StreamHandler = struct {
         }, .{ .forever = {} });
     }
 
-    pub fn promptStart(self: *StreamHandler) !void {
+    pub fn promptStart(self: *StreamHandler, aid: ?[]const u8, redraw: bool) !void {
+        _ = aid;
         self.terminal.markSemanticPrompt(.prompt);
+        self.terminal.modes.shell_redraws_prompt = redraw;
     }
 
     pub fn promptEnd(self: *StreamHandler) !void {