terminal: add more integrity assertions

src/terminal/Screen.zig

@@ -709,6 +709,8 @@ pub const Scroll = union(enum) {
 
 /// Scroll the viewport of the terminal grid.
 pub fn scroll(self: *Screen, behavior: Scroll) void {
+    defer self.assertIntegrity();
+
     // No matter what, scrolling marks our image state as dirty since
     // it could move placements. If there are no placements or no images
     // this is still a very cheap operation.
@@ -726,6 +728,8 @@ pub fn scroll(self: *Screen, behavior: Scroll) void {
 /// See PageList.scrollClear. In addition to that, we reset the cursor
 /// to be on top.
 pub fn scrollClear(self: *Screen) !void {
+    defer self.assertIntegrity();
+
     try self.pages.scrollClear();
     self.cursorReload();
 
@@ -748,6 +752,8 @@ pub fn eraseRows(
     tl: point.Point,
     bl: ?point.Point,
 ) void {
+    defer self.assertIntegrity();
+
     // Erase the rows
     self.pages.eraseRows(tl, bl);
 
@@ -769,6 +775,8 @@ pub fn clearRows(
     bl: ?point.Point,
     protected: bool,
 ) void {
+    defer self.assertIntegrity();
+
     var it = self.pages.pageIterator(.right_down, tl, bl);
     while (it.next()) |chunk| {
         for (chunk.rows()) |*row| {
@@ -842,6 +850,8 @@ pub fn clearCells(
     }
 
     @memset(cells, self.blankCell());
+    page.assertIntegrity();
+    self.assertIntegrity();
 }
 
 /// Clear cells but only if they are not protected.
@@ -856,6 +866,9 @@ pub fn clearUnprotectedCells(
         const cell_multi: [*]Cell = @ptrCast(cell);
         self.clearCells(page, row, cell_multi[0..1]);
     }
+
+    page.assertIntegrity();
+    self.assertIntegrity();
 }
 
 /// Clears the prompt lines if the cursor is currently at a prompt. This
@@ -977,6 +990,7 @@ fn resizeInternal(
     // If our cursor was updated, we do a full reload so all our cursor
     // state is correct.
     self.cursorReload();
+    self.assertIntegrity();
 }
 
 /// Set a style attribute for the current cursor.
@@ -1192,6 +1206,7 @@ pub fn manualStyleUpdate(self: *Screen) !void {
     self.cursor.style_id = md.id;
     self.cursor.style_ref = &md.ref;
     if (cursor_reload) self.cursorReload();
+    self.assertIntegrity();
 }
 
 /// Append a grapheme to the given cell within the current cursor row.

src/terminal/Terminal.zig

@@ -223,6 +223,10 @@ pub fn print(self: *Terminal, c: u21) !void {
     // If we're not on the main display, do nothing for now
     if (self.status_display != .main) return;
 
+    // After doing any printing, wrapping, scrolling, etc. we want to ensure
+    // that our screen remains in a consistent state.
+    defer self.screen.assertIntegrity();
+
     // Our right margin depends where our cursor is now.
     const right_limit = if (self.screen.cursor.x > self.scrolling_region.right)
         self.cols
@@ -470,6 +474,8 @@ fn printCell(
     unmapped_c: u21,
     wide: Cell.Wide,
 ) void {
+    defer self.screen.assertIntegrity();
+
     // TODO: spacers should use a bgcolor only cell
 
     const c: u21 = c: {
@@ -627,6 +633,9 @@ fn printWrap(self: *Terminal) !void {
     // New line must inherit semantic prompt of the old line
     self.screen.cursor.page_row.semantic_prompt = old_prompt;
     self.screen.cursor.page_row.wrap_continuation = true;
+
+    // Assure that our screen is consistent
+    self.screen.assertIntegrity();
 }
 
 /// Set the charset into the given slot.
@@ -876,6 +885,9 @@ pub fn restoreCursor(self: *Terminal) !void {
         @min(saved.x, self.cols - 1),
         @min(saved.y, self.rows - 1),
     );
+
+    // Ensure our screen is consistent
+    self.screen.assertIntegrity();
 }
 
 /// Set the character protection mode for the terminal.
@@ -1315,6 +1327,9 @@ pub fn insertLines(self: *Terminal, count: usize) void {
                 const dst_row = dst.*;
                 dst.* = src.*;
                 src.* = dst_row;
+
+                // Ensure what we did didn't corrupt the page
+                p.page.data.assertIntegrity();
                 continue;
             }
 

src/terminal/page.zig

@@ -176,7 +176,6 @@ pub const Page = struct {
 
     pub const IntegrityError = error{
         UnmarkedGraphemeRow,
-        MarkedGraphemeRow,
         MissingGraphemeData,
         InvalidGraphemeCount,
         MissingStyle,
@@ -267,16 +266,6 @@ pub const Page = struct {
                     );
                     return IntegrityError.UnmarkedGraphemeRow;
                 }
-            } else {
-                // If no cells in a row have grapheme data, the row must
-                // not be marked as having grapheme data.
-                if (row.grapheme) {
-                    log.warn(
-                        "page integrity violation y={} row marked but no grapheme data",
-                        .{y},
-                    );
-                    return IntegrityError.MarkedGraphemeRow;
-                }
             }
         }
 
@@ -406,6 +395,9 @@ pub const Page = struct {
             dst_row,
             src_row,
         );
+
+        // We should remain consistent
+        self.assertIntegrity();
     }
 
     /// Clone a single row from another page into this page.
@@ -454,6 +446,9 @@ pub const Page = struct {
                 dst_cell.style_id = md.id;
             }
         }
+
+        // The final page should remain consistent
+        self.assertIntegrity();
     }
 
     /// Get a single row. y must be valid.
@@ -501,6 +496,8 @@ pub const Page = struct {
         dst_left: usize,
         len: usize,
     ) void {
+        defer self.assertIntegrity();
+
         const src_cells = src_row.cells.ptr(self.memory)[src_left .. src_left + len];
         const dst_cells = dst_row.cells.ptr(self.memory)[dst_left .. dst_left + len];
 
@@ -527,6 +524,9 @@ pub const Page = struct {
                 dst.content_tag = .codepoint;
                 self.moveGrapheme(src, dst);
             }
+
+            // The destination row must be marked
+            dst_row.grapheme = true;
         }
 
         // Clear our source row now that the copy is complete
@@ -544,6 +544,8 @@ pub const Page = struct {
         left: usize,
         end: usize,
     ) void {
+        defer self.assertIntegrity();
+
         const cells = row.cells.ptr(self.memory)[left..end];
         if (row.grapheme) {
             for (cells) |*cell| {
@@ -572,6 +574,8 @@ pub const Page = struct {
 
     /// Append a codepoint to the given cell as a grapheme.
     pub fn appendGrapheme(self: *Page, row: *Row, cell: *Cell, cp: u21) Allocator.Error!void {
+        defer self.assertIntegrity();
+
         if (comptime std.debug.runtime_safety) assert(cell.hasText());
 
         const cell_offset = getOffset(Cell, self.memory, cell);
@@ -640,7 +644,7 @@ pub const Page = struct {
 
     /// Move the graphemes from one cell to another. This can't fail
     /// because we avoid any allocations since we're just moving data.
-    pub fn moveGrapheme(self: *const Page, src: *Cell, dst: *Cell) void {
+    pub fn moveGrapheme(self: *Page, src: *Cell, dst: *Cell) void {
         if (comptime std.debug.runtime_safety) {
             assert(src.hasGrapheme());
             assert(!dst.hasGrapheme());
@@ -654,10 +658,12 @@ pub const Page = struct {
         map.removeByPtr(entry.key_ptr);
         map.putAssumeCapacity(dst_offset, value);
         src.content_tag = .codepoint;
+        dst.content_tag = .codepoint_grapheme;
     }
 
     /// Clear the graphemes for a given cell.
     pub fn clearGrapheme(self: *Page, row: *Row, cell: *Cell) void {
+        defer self.assertIntegrity();
         if (comptime std.debug.runtime_safety) assert(cell.hasGrapheme());
 
         // Get our entry in the map, which must exist
@@ -692,6 +698,8 @@ pub const Page = struct {
         // the places we call this is from insertBlanks where the cells have
         // already swapped cell data but not grapheme data.
 
+        defer self.assertIntegrity();
+
         // Get our entry in the map, which must exist
         const src_offset = getOffset(Cell, self.memory, src);
         var map = self.grapheme_map.map(self.memory);
@@ -1575,7 +1583,7 @@ test "Page moveCells graphemes" {
     defer page.deinit();
 
     // Write
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         rac.cell.* = .{
             .content_tag = .codepoint,
@@ -1587,11 +1595,11 @@ test "Page moveCells graphemes" {
 
     const src = page.getRow(0);
     const dst = page.getRow(1);
-    page.moveCells(src, 0, dst, 0, page.capacity.cols);
+    page.moveCells(src, 0, dst, 0, page.size.cols);
     try testing.expectEqual(original_count, page.graphemeCount());
 
     // New rows should have text
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 1);
         try testing.expectEqual(
             @as(u21, @intCast(x + 1)),
@@ -1605,7 +1613,7 @@ test "Page moveCells graphemes" {
     }
 
     // Old row should be blank
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         try testing.expectEqual(
             @as(u21, 0),
@@ -1623,7 +1631,7 @@ test "Page verifyIntegrity graphemes good" {
     defer page.deinit();
 
     // Write
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         rac.cell.* = .{
             .content_tag = .codepoint,
@@ -1644,7 +1652,7 @@ test "Page verifyIntegrity grapheme row not marked" {
     defer page.deinit();
 
     // Write
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         rac.cell.* = .{
             .content_tag = .codepoint,
@@ -1662,32 +1670,6 @@ test "Page verifyIntegrity grapheme row not marked" {
     );
 }
 
-test "Page verifyIntegrity text row marked as grapheme" {
-    var page = try Page.init(.{
-        .cols = 10,
-        .rows = 10,
-        .styles = 8,
-    });
-    defer page.deinit();
-
-    // Write
-    for (0..page.capacity.cols) |x| {
-        const rac = page.getRowAndCell(x, 0);
-        rac.cell.* = .{
-            .content_tag = .codepoint,
-            .content = .{ .codepoint = @intCast(x + 1) },
-        };
-    }
-
-    // Make invalid by unmarking the row
-    page.getRow(0).grapheme = true;
-
-    try testing.expectError(
-        Page.IntegrityError.MarkedGraphemeRow,
-        page.verifyIntegrity(testing.allocator),
-    );
-}
-
 test "Page verifyIntegrity styles good" {
     var page = try Page.init(.{
         .cols = 10,
@@ -1702,7 +1684,7 @@ test "Page verifyIntegrity styles good" {
     } });
 
     // Write
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         rac.row.styled = true;
         rac.cell.* = .{
@@ -1730,7 +1712,7 @@ test "Page verifyIntegrity styles ref count mismatch" {
     } });
 
     // Write
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         rac.row.styled = true;
         rac.cell.* = .{
@@ -1769,7 +1751,7 @@ test "Page verifyIntegrity styles extra" {
     md2.ref += 1;
 
     // Write
-    for (0..page.capacity.cols) |x| {
+    for (0..page.size.cols) |x| {
         const rac = page.getRowAndCell(x, 0);
         rac.row.styled = true;
         rac.cell.* = .{