Merge pull request #724 from mitchellh/fuzz

Fix a couple crashes found while fuzzing

src/terminal/Terminal.zig

@@ -1413,6 +1413,25 @@ pub fn cursorLeft(self: *Terminal, count_req: usize) void {
     else
         self.scrolling_region.left;
 
+    // Handle some edge cases when our cursor is already on the left margin.
+    if (self.screen.cursor.x == left_margin) {
+        switch (wrap_mode) {
+            // In reverse mode, if we're already before the top margin
+            // then we just set our cursor to the top-left and we're done.
+            .reverse => if (self.screen.cursor.y <= top) {
+                self.screen.cursor.x = left_margin;
+                self.screen.cursor.y = top;
+                return;
+            },
+
+            // Handled in while loop
+            .reverse_extended => {},
+
+            // Handled above
+            .none => unreachable,
+        }
+    }
+
     while (true) {
         // We can move at most to the left margin.
         const max = self.screen.cursor.x - left_margin;
@@ -1437,8 +1456,10 @@ pub fn cursorLeft(self: *Terminal, count_req: usize) void {
         }
 
         // If our previous line is not wrapped then we are done.
+        if (wrap_mode != .reverse_extended) {
             const row = self.screen.getRow(.{ .active = self.screen.cursor.y - 1 });
-        if (wrap_mode != .reverse_extended and !row.isWrapped()) break;
+            if (!row.isWrapped()) break;
+        }
         self.screen.cursor.y -= 1;
         self.screen.cursor.x = right_margin;
         count -= 1;
@@ -1541,7 +1562,7 @@ pub fn horizontalTabBack(self: *Terminal) !void {
 
     while (true) {
         // If we're already at the edge of the screen, then we're done.
-        if (self.screen.cursor.x == left_limit) return;
+        if (self.screen.cursor.x <= left_limit) return;
 
         // Move the cursor left
         self.screen.cursor.x -= 1;
@@ -1634,7 +1655,7 @@ pub fn insertBlanks(self: *Terminal, count: usize) void {
 
     // Determine our indexes.
     const start = self.screen.cursor.x;
-    const pivot = self.screen.cursor.x + count;
+    const pivot = @min(self.screen.cursor.x + count, right_limit);
 
     // This is the number of spaces we have left to shift existing data.
     // If count is bigger than the available space left after the cursor,
@@ -2733,6 +2754,26 @@ test "Terminal: horizontal tabs with left margin in origin mode" {
     }
 }
 
+test "Terminal: horizontal tab back with cursor before left margin" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 20, 5);
+    defer t.deinit(alloc);
+
+    t.modes.set(.origin, true);
+    t.saveCursor();
+    t.modes.set(.enable_left_and_right_margin, true);
+    t.setLeftAndRightMargin(5, 0);
+    t.restoreCursor();
+    try t.horizontalTabBack();
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("X", str);
+    }
+}
+
 test "Terminal: cursorPos resets wrap" {
     const alloc = testing.allocator;
     var t = try init(alloc, 5, 5);
@@ -4248,6 +4289,25 @@ test "Terminal: insertBlanks outside left/right scroll region" {
     }
 }
 
+test "Terminal: insertBlanks left/right scroll region large count" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 10, 10);
+    defer t.deinit(alloc);
+
+    t.modes.set(.origin, true);
+    t.modes.set(.enable_left_and_right_margin, true);
+    t.setLeftAndRightMargin(3, 5);
+    t.setCursorPos(1, 1);
+    t.insertBlanks(140);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("  X", str);
+    }
+}
+
 test "Terminal: insert mode with space" {
     const alloc = testing.allocator;
     var t = try init(alloc, 10, 2);
@@ -5914,6 +5974,24 @@ test "Terminal: cursorLeft reverse wrap with no soft wrap" {
     }
 }
 
+test "Terminal: cursorLeft reverse wrap before left margin" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    t.modes.set(.wraparound, true);
+    t.modes.set(.reverse_wrap, true);
+    t.setTopAndBottomMargin(3, 0);
+    t.cursorLeft(1);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("\n\nX", str);
+    }
+}
+
 test "Terminal: cursorLeft extended reverse wrap" {
     const alloc = testing.allocator;
     var t = try init(alloc, 5, 5);

src/terminal/stream.zig

@@ -926,13 +926,19 @@ pub fn Stream(comptime Handler: type) type {
                 },
 
                 // ICH - Insert Blanks
-                // TODO: test
+                '@' => switch (action.intermediates.len) {
-                '@' => if (@hasDecl(T, "insertBlanks")) switch (action.params.len) {
+                    0 => if (@hasDecl(T, "insertBlanks")) switch (action.params.len) {
                         0 => try self.handler.insertBlanks(1),
                         1 => try self.handler.insertBlanks(action.params[0]),
                         else => log.warn("invalid ICH command: {}", .{action}),
                     } else log.warn("unimplemented CSI callback: {}", .{action}),
 
+                    else => log.warn(
+                        "ignoring unimplemented CSI @: {}",
+                        .{action},
+                    ),
+                },
+
                 // DECSASD - Select Active Status Display
                 '}' => {
                     const success = decsasd: {
@@ -1572,3 +1578,23 @@ test "stream: XTSHIFTESCAPE" {
     try s.nextSlice("\x1B[>1s");
     try testing.expect(s.handler.escape.? == true);
 }
+
+test "stream: insert characters" {
+    const H = struct {
+        const Self = @This();
+        called: bool = false,
+
+        pub fn insertBlanks(self: *Self, v: u16) !void {
+            _ = v;
+            self.called = true;
+        }
+    };
+
+    var s: Stream(H) = .{ .handler = .{} };
+    for ("\x1B[42@") |c| try s.next(c);
+    try testing.expect(s.handler.called);
+
+    s.handler.called = false;
+    for ("\x1B[?42@") |c| try s.next(c);
+    try testing.expect(!s.handler.called);
+}

website/app/vt/cub/page.mdx

@@ -12,8 +12,7 @@ or equal to 0, adjust `n` to be 1. If `n` is omitted, `n` defaults to 1.
 This sequence always unsets the pending wrap state.
 
 The leftmost boundary the cursor can move to is determined by the current
-cursor column and the [left margin](#TODO). If the cursor begins to the left
+cursor column and the [left margin](#TODO). If the cursor begins to the left of the left margin, modify the left margin to be the leftmost column
-of the left margin, modify the left margin to be the leftmost column
 for the duration of the sequence. The leftmost column the cursor can be on
 is the left margin.
 
@@ -142,5 +141,21 @@ printf "X"
 |A_________|
 |B_________|
 |_________Xc
-``g
+```
+
+### CUB V-6: Reverse Wrap Outside of Margins
+
+```bash
+printf "\033[1;1H"
+printf "\033[0J"
+printf "\033[?45h"
+printf "\033[3r"
+printf "\b"
+printf "X"
+```
+
+```
+|__________|
+|__________|
+|Xc________|
 ```