From 05d6315e822f6574c6586348540d8626cbbd1cb7 Mon Sep 17 00:00:00 2001 From: Mitchell Hashimoto Date: Sat, 22 Nov 2025 21:06:31 -0800 Subject: [PATCH] terminal: add a SlidingWindow2 that uses highlights --- src/terminal/search.zig | 1 + src/terminal/search/sliding_window2.zig | 1400 +++++++++++++++++++++++ 2 files changed, 1401 insertions(+) create mode 100644 src/terminal/search/sliding_window2.zig diff --git a/src/terminal/search.zig b/src/terminal/search.zig index e69603c25..1ac18515c 100644 --- a/src/terminal/search.zig +++ b/src/terminal/search.zig @@ -19,4 +19,5 @@ test { // Non-public APIs _ = @import("search/sliding_window.zig"); + _ = @import("search/sliding_window2.zig"); } diff --git a/src/terminal/search/sliding_window2.zig b/src/terminal/search/sliding_window2.zig new file mode 100644 index 000000000..6aad0bff9 --- /dev/null +++ b/src/terminal/search/sliding_window2.zig @@ -0,0 +1,1400 @@ +const std = @import("std"); +const assert = @import("../../quirks.zig").inlineAssert; +const Allocator = std.mem.Allocator; +const CircBuf = @import("../../datastruct/main.zig").CircBuf; +const terminal = @import("../main.zig"); +const point = terminal.point; +const size = terminal.size; +const PageList = terminal.PageList; +const Pin = PageList.Pin; +const Selection = terminal.Selection; +const Screen = terminal.Screen; +const PageFormatter = @import("../formatter.zig").PageFormatter; +const FlattenedHighlight = terminal.highlight.Flattened; + +/// Searches page nodes via a sliding window. The sliding window maintains +/// the invariant that data isn't pruned until (1) we've searched it and +/// (2) we've accounted for overlaps across pages to fit the needle. +/// +/// The sliding window is first initialized empty. Pages are then appended +/// in the order to search them. The sliding window supports both a forward +/// and reverse order specified via `init`. The pages should be appended +/// in the correct order matching the search direction. +/// +/// All appends grow the window. The window is only pruned when a search +/// is done (positive or negative match) via `next()`. +/// +/// To avoid unnecessary memory growth, the recommended usage is to +/// call `next()` until it returns null and then `append` the next page +/// and repeat the process. This will always maintain the minimum +/// required memory to search for the needle. +/// +/// The caller is responsible for providing the pages and ensuring they're +/// in the proper order. The SlidingWindow itself doesn't own the pages, but +/// it will contain pointers to them in order to return selections. If any +/// pages become invalid, the caller should clear the sliding window and +/// start over. +pub const SlidingWindow = struct { + /// The allocator to use for all the data within this window. We + /// store this rather than passing it around because its already + /// part of multiple elements (eg. Meta's CellMap) and we want to + /// ensure we always use a consistent allocator. Additionally, only + /// a small amount of sliding windows are expected to be in use + /// at any one time so the memory overhead isn't that large. + alloc: Allocator, + + /// The data buffer is a circular buffer of u8 that contains the + /// encoded page text that we can use to search for the needle. + data: DataBuf, + + /// The meta buffer is a circular buffer that contains the metadata + /// about the pages we're searching. This usually isn't that large + /// so callers must iterate through it to find the offset to map + /// data to meta. + meta: MetaBuf, + + /// Buffer that can fit any amount of chunks necessary for next + /// to never fail allocation. + chunk_buf: std.MultiArrayList(FlattenedHighlight.Chunk), + + /// Offset into data for our current state. This handles the + /// situation where our search moved through meta[0] but didn't + /// do enough to prune it. + data_offset: usize = 0, + + /// The needle we're searching for. Does own the memory. + needle: []const u8, + + /// The search direction. If the direction is forward then pages should + /// be appended in forward linked list order from the PageList. If the + /// direction is reverse then pages should be appended in reverse order. + /// + /// This is important because in most cases, a reverse search is going + /// to be more desirable to search from the end of the active area + /// backwards so more recent data is found first. Supporting both is + /// trivial though and will let us do more complex optimizations in the + /// future (e.g. starting from the viewport and doing a forward/reverse + /// concurrently from that point). + direction: Direction, + + /// A buffer to store the overlap search data. This is used to search + /// overlaps between pages where the match starts on one page and + /// ends on another. The length is always `needle.len * 2`. + overlap_buf: []u8, + + const Direction = enum { forward, reverse }; + const DataBuf = CircBuf(u8, 0); + const MetaBuf = CircBuf(Meta, undefined); + const Meta = struct { + node: *PageList.List.Node, + cell_map: std.ArrayList(point.Coordinate), + + pub fn deinit(self: *Meta, alloc: Allocator) void { + self.cell_map.deinit(alloc); + } + }; + + pub fn init( + alloc: Allocator, + direction: Direction, + needle_unowned: []const u8, + ) Allocator.Error!SlidingWindow { + var data = try DataBuf.init(alloc, 0); + errdefer data.deinit(alloc); + + var meta = try MetaBuf.init(alloc, 0); + errdefer meta.deinit(alloc); + + const needle = try alloc.dupe(u8, needle_unowned); + errdefer alloc.free(needle); + switch (direction) { + .forward => {}, + .reverse => std.mem.reverse(u8, needle), + } + + const overlap_buf = try alloc.alloc(u8, needle.len * 2); + errdefer alloc.free(overlap_buf); + + return .{ + .alloc = alloc, + .data = data, + .meta = meta, + .chunk_buf = .empty, + .needle = needle, + .direction = direction, + .overlap_buf = overlap_buf, + }; + } + + pub fn deinit(self: *SlidingWindow) void { + self.alloc.free(self.overlap_buf); + self.alloc.free(self.needle); + self.chunk_buf.deinit(self.alloc); + self.data.deinit(self.alloc); + + var meta_it = self.meta.iterator(.forward); + while (meta_it.next()) |meta| meta.deinit(self.alloc); + self.meta.deinit(self.alloc); + } + + /// Clear all data but retain allocated capacity. + pub fn clearAndRetainCapacity(self: *SlidingWindow) void { + var meta_it = self.meta.iterator(.forward); + while (meta_it.next()) |meta| meta.deinit(self.alloc); + self.meta.clear(); + self.data.clear(); + self.data_offset = 0; + } + + /// Search the window for the next occurrence of the needle. As + /// the window moves, the window will prune itself while maintaining + /// the invariant that the window is always big enough to contain + /// the needle. + /// + /// This returns a flattened highlight on a match. The + /// flattened highlight requires allocation and is therefore more expensive + /// than a normal selection, but it is more efficient to render since it + /// has all the information without having to dereference pointers into + /// the terminal state. + /// + /// The flattened highlight chunks reference internal memory for this + /// sliding window and are only valid until the next call to `next()` + /// or `append()`. If the caller wants to retain the flattened highlight + /// then they should clone it. + pub fn next(self: *SlidingWindow) ?FlattenedHighlight { + const slices = slices: { + // If we have less data then the needle then we can't possibly match + const data_len = self.data.len(); + if (data_len < self.needle.len) return null; + + break :slices self.data.getPtrSlice( + self.data_offset, + data_len - self.data_offset, + ); + }; + + // Search the first slice for the needle. + if (std.mem.indexOf(u8, slices[0], self.needle)) |idx| { + return self.highlight( + idx, + self.needle.len, + ); + } + + // Search the overlap buffer for the needle. + if (slices[0].len > 0 and slices[1].len > 0) overlap: { + // Get up to needle.len - 1 bytes from each side (as much as + // we can) and store it in the overlap buffer. + const prefix: []const u8 = prefix: { + const len = @min(slices[0].len, self.needle.len - 1); + const idx = slices[0].len - len; + break :prefix slices[0][idx..]; + }; + const suffix: []const u8 = suffix: { + const len = @min(slices[1].len, self.needle.len - 1); + break :suffix slices[1][0..len]; + }; + const overlap_len = prefix.len + suffix.len; + assert(overlap_len <= self.overlap_buf.len); + @memcpy(self.overlap_buf[0..prefix.len], prefix); + @memcpy(self.overlap_buf[prefix.len..overlap_len], suffix); + + // Search the overlap + const idx = std.mem.indexOf( + u8, + self.overlap_buf[0..overlap_len], + self.needle, + ) orelse break :overlap; + + // We found a match in the overlap buffer. We need to map the + // index back to the data buffer in order to get our selection. + return self.highlight( + slices[0].len - prefix.len + idx, + self.needle.len, + ); + } + + // Search the last slice for the needle. + if (std.mem.indexOf(u8, slices[1], self.needle)) |idx| { + return self.highlight( + slices[0].len + idx, + self.needle.len, + ); + } + + // No match. We keep `needle.len - 1` bytes available to + // handle the future overlap case. + var meta_it = self.meta.iterator(.reverse); + prune: { + var saved: usize = 0; + while (meta_it.next()) |meta| { + const needed = self.needle.len - 1 - saved; + if (meta.cell_map.items.len >= needed) { + // We save up to this meta. We set our data offset + // to exactly where it needs to be to continue + // searching. + self.data_offset = meta.cell_map.items.len - needed; + break; + } + + saved += meta.cell_map.items.len; + } else { + // If we exited the while loop naturally then we + // never got the amount we needed and so there is + // nothing to prune. + assert(saved < self.needle.len - 1); + break :prune; + } + + const prune_count = self.meta.len() - meta_it.idx; + if (prune_count == 0) { + // This can happen if we need to save up to the first + // meta value to retain our window. + break :prune; + } + + // We can now delete all the metas up to but NOT including + // the meta we found through meta_it. + meta_it = self.meta.iterator(.forward); + var prune_data_len: usize = 0; + for (0..prune_count) |_| { + const meta = meta_it.next().?; + prune_data_len += meta.cell_map.items.len; + meta.deinit(self.alloc); + } + self.meta.deleteOldest(prune_count); + self.data.deleteOldest(prune_data_len); + } + + // Our data offset now moves to needle.len - 1 from the end so + // that we can handle the overlap case. + self.data_offset = self.data.len() - self.needle.len + 1; + + self.assertIntegrity(); + return null; + } + + /// Return a flattened highlight for the given start and length. + /// + /// The flattened highlight can be used to render the highlight + /// in the most efficent way because it doesn't require a terminal + /// lock to access terminal data to compare whether some viewport + /// matches the highlight (because it doesn't need to traverse + /// the page nodes). + /// + /// The start index is assumed to be relative to the offset. i.e. + /// index zero is actually at `self.data[self.data_offset]`. The + /// selection will account for the offset. + fn highlight( + self: *SlidingWindow, + start_offset: usize, + len: usize, + ) terminal.highlight.Flattened { + const start = start_offset + self.data_offset; + const end = start + len - 1; + if (comptime std.debug.runtime_safety) { + assert(start < self.data.len()); + assert(start + len <= self.data.len()); + } + + // Clear our previous chunk buffer to store this result + self.chunk_buf.clearRetainingCapacity(); + var result: terminal.highlight.Flattened = .empty; + + // Go through the meta nodes to find our start. + const tl: struct { + /// If non-null, we need to continue searching for the bottom-right. + br: ?struct { + it: MetaBuf.Iterator, + consumed: usize, + }, + + /// Data to prune, both are lengths. + prune: struct { + meta: usize, + data: usize, + }, + } = tl: { + var meta_it = self.meta.iterator(.forward); + var meta_consumed: usize = 0; + while (meta_it.next()) |meta| { + // Always increment our consumed count so that our index + // is right for the end search if we do it. + const prior_meta_consumed = meta_consumed; + meta_consumed += meta.cell_map.items.len; + + // meta_i is the index we expect to find the match in the + // cell map within this meta if it contains it. + const meta_i = start - prior_meta_consumed; + + // This meta doesn't contain the match. This means we + // can also prune this set of data because we only look + // forward. + if (meta_i >= meta.cell_map.items.len) continue; + + // Now we look for the end. In MOST cases it is the same as + // our starting chunk because highlights are usually small and + // not on a boundary, so let's optimize for that. + const end_i = end - prior_meta_consumed; + if (end_i < meta.cell_map.items.len) { + @branchHint(.likely); + + // The entire highlight is within this meta. + const start_map = meta.cell_map.items[meta_i]; + const end_map = meta.cell_map.items[end_i]; + result.top_x = start_map.x; + result.bot_x = end_map.x; + self.chunk_buf.appendAssumeCapacity(.{ + .node = meta.node, + .start = @intCast(start_map.y), + .end = @intCast(end_map.y + 1), + }); + + break :tl .{ + .br = null, + .prune = .{ + .meta = meta_it.idx - 1, + .data = prior_meta_consumed, + }, + }; + } else { + // We found the meta that contains the start of the match + // only. Consume this entire node from our start offset. + const map = meta.cell_map.items[meta_i]; + result.top_x = map.x; + self.chunk_buf.appendAssumeCapacity(.{ + .node = meta.node, + .start = @intCast(map.y), + .end = meta.node.data.size.rows, + }); + + break :tl .{ + .br = .{ + .it = meta_it, + .consumed = meta_consumed, + }, + .prune = .{ + .meta = meta_it.idx - 1, + .data = prior_meta_consumed, + }, + }; + } + } else { + // Precondition that the start index is within the data buffer. + unreachable; + } + }; + + // Search for our end. + if (tl.br) |br| { + var meta_it = br.it; + var meta_consumed: usize = br.consumed; + while (meta_it.next()) |meta| { + // meta_i is the index we expect to find the match in the + // cell map within this meta if it contains it. + const meta_i = end - meta_consumed; + if (meta_i >= meta.cell_map.items.len) { + // This meta doesn't contain the match. We still add it + // to our results because we want the full flattened list. + self.chunk_buf.appendAssumeCapacity(.{ + .node = meta.node, + .start = 0, + .end = meta.node.data.size.rows, + }); + + meta_consumed += meta.cell_map.items.len; + continue; + } + + // We found it + const map = meta.cell_map.items[meta_i]; + result.bot_x = map.x; + self.chunk_buf.appendAssumeCapacity(.{ + .node = meta.node, + .start = 0, + .end = @intCast(map.y + 1), + }); + break; + } else { + // Precondition that the end index is within the data buffer. + unreachable; + } + } + + // Our offset into the current meta block is the start index + // minus the amount of data fully consumed. We then add one + // to move one past the match so we don't repeat it. + self.data_offset = start - tl.prune.data + 1; + + // If we went beyond our initial meta node we can prune. + if (tl.prune.meta > 0) { + // Deinit all our memory in the meta blocks prior to our + // match. + var meta_it = self.meta.iterator(.forward); + var meta_consumed: usize = 0; + for (0..tl.prune.meta) |_| { + const meta: *Meta = meta_it.next().?; + meta_consumed += meta.cell_map.items.len; + meta.deinit(self.alloc); + } + if (comptime std.debug.runtime_safety) { + assert(meta_it.idx == tl.prune.meta); + assert(meta_it.next().?.node == self.chunk_buf.items(.node)[0]); + } + self.meta.deleteOldest(tl.prune.meta); + + // Delete all the data up to our current index. + assert(tl.prune.data > 0); + self.data.deleteOldest(tl.prune.data); + } + + switch (self.direction) { + .forward => {}, + .reverse => { + if (self.chunk_buf.len > 1) { + // Reverse all our chunks. This should be pretty obvious why. + const slice = self.chunk_buf.slice(); + const nodes = slice.items(.node); + const starts = slice.items(.start); + const ends = slice.items(.end); + std.mem.reverse(*PageList.List.Node, nodes); + std.mem.reverse(size.CellCountInt, starts); + std.mem.reverse(size.CellCountInt, ends); + + // Now normally with forward traversal with multiple pages, + // the suffix of the first page and the prefix of the last + // page are used. + // + // For a reverse traversal, this is inverted (since the + // pages are in reverse order we get the suffix of the last + // page and the prefix of the first page). So we need to + // invert this. + // + // We DON'T need to do this for any middle pages because + // they always use the full page. + // + // We DON'T need to do this for chunks.len == 1 because + // the pages themselves aren't reversed and we don't have + // any prefix/suffix problems. + // + // This is a fixup that makes our start/end match the + // same logic as the loops above if they were in forward + // order. + assert(nodes.len >= 2); + starts[0] = ends[0] - 1; + ends[0] = nodes[0].data.size.rows; + ends[nodes.len - 1] = starts[nodes.len - 1] + 1; + starts[nodes.len - 1] = 0; + } + + // X values also need to be reversed since the top/bottom + // are swapped for the nodes. + const top_x = result.top_x; + result.top_x = result.bot_x; + result.bot_x = top_x; + }, + } + + // Copy over our MultiArrayList so it points to the proper memory. + result.chunks = self.chunk_buf; + return result; + } + + /// Add a new node to the sliding window. This will always grow + /// the sliding window; data isn't pruned until it is consumed + /// via a search (via next()). + /// + /// Returns the number of bytes of content added to the sliding window. + /// The total bytes will be larger since this omits metadata, but it is + /// an accurate measure of the text content size added. + pub fn append( + self: *SlidingWindow, + node: *PageList.List.Node, + ) Allocator.Error!usize { + // Initialize our metadata for the node. + var meta: Meta = .{ + .node = node, + .cell_map = .empty, + }; + errdefer meta.deinit(self.alloc); + + // This is suboptimal but we need to encode the page once to + // temporary memory, and then copy it into our circular buffer. + // In the future, we should benchmark and see if we can encode + // directly into the circular buffer. + var encoded: std.Io.Writer.Allocating = .init(self.alloc); + defer encoded.deinit(); + + // Encode the page into the buffer. + const formatter: PageFormatter = formatter: { + var formatter: PageFormatter = .init(&meta.node.data, .plain); + formatter.point_map = .{ + .alloc = self.alloc, + .map = &meta.cell_map, + }; + break :formatter formatter; + }; + formatter.format(&encoded.writer) catch { + // writer uses anyerror but the only realistic error on + // an ArrayList is out of memory. + return error.OutOfMemory; + }; + assert(meta.cell_map.items.len == encoded.written().len); + + // If the node we're adding isn't soft-wrapped, we add the + // trailing newline. + const row = node.data.getRow(node.data.size.rows - 1); + if (!row.wrap) { + encoded.writer.writeByte('\n') catch return error.OutOfMemory; + try meta.cell_map.append( + self.alloc, + meta.cell_map.getLastOrNull() orelse .{ + .x = 0, + .y = 0, + }, + ); + } + + // Get our written data. If we're doing a reverse search then we + // need to reverse all our encodings. + const written = encoded.written(); + switch (self.direction) { + .forward => {}, + .reverse => { + std.mem.reverse(u8, written); + std.mem.reverse(point.Coordinate, meta.cell_map.items); + }, + } + + // Ensure our buffers are big enough to store what we need. + try self.data.ensureUnusedCapacity(self.alloc, written.len); + try self.meta.ensureUnusedCapacity(self.alloc, 1); + try self.chunk_buf.ensureTotalCapacity(self.alloc, self.meta.capacity()); + + // Append our new node to the circular buffer. + self.data.appendSliceAssumeCapacity(written); + self.meta.appendAssumeCapacity(meta); + + self.assertIntegrity(); + return written.len; + } + + /// Only for tests! + fn testChangeNeedle(self: *SlidingWindow, new: []const u8) void { + assert(new.len == self.needle.len); + self.alloc.free(self.needle); + self.needle = self.alloc.dupe(u8, new) catch unreachable; + } + + fn assertIntegrity(self: *const SlidingWindow) void { + if (comptime !std.debug.runtime_safety) return; + + // We don't run integrity checks on Valgrind because its soooooo slow, + // Valgrind is our integrity checker, and we run these during unit + // tests (non-Valgrind) anyways so we're verifying anyways. + if (std.valgrind.runningOnValgrind() > 0) return; + + // Integrity check: verify our data matches our metadata exactly. + var meta_it = self.meta.iterator(.forward); + var data_len: usize = 0; + while (meta_it.next()) |m| data_len += m.cell_map.items.len; + assert(data_len == self.data.len()); + + // Integrity check: verify our data offset is within bounds. + assert(self.data_offset < self.data.len()); + } +}; + +test "SlidingWindow empty on init" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "boo!"); + defer w.deinit(); + try testing.expectEqual(0, w.data.len()); + try testing.expectEqual(0, w.meta.len()); +} + +test "SlidingWindow single append" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "boo!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("hello. boo! hello. boo!"); + + // We want to test single-page cases. + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + + // We should be able to find two matches. + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 7, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start)); + try testing.expectEqual(point.Point{ .active = .{ + .x = 10, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end)); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 19, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start)); + try testing.expectEqual(point.Point{ .active = .{ + .x = 22, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end)); + } + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); +} + +test "SlidingWindow single append no match" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "nope!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("hello. boo! hello. boo!"); + + // We want to test single-page cases. + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + + // No matches + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // Should still keep the page + try testing.expectEqual(1, w.meta.len()); +} + +test "SlidingWindow two pages" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "boo!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("boo!"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\n"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + try s.testWriteString("hello. boo!"); + + // Add both pages + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node.next.?); + + // Search should find two matches + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 76, + .y = 22, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 79, + .y = 22, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 7, + .y = 23, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 10, + .y = 23, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); +} + +test "SlidingWindow two pages match across boundary" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "hello, world"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("hell"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("o, world!"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + + // Add both pages + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node.next.?); + + // Search should find a match + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 76, + .y = 22, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 7, + .y = 23, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // We shouldn't prune because we don't have enough space + try testing.expectEqual(2, w.meta.len()); +} + +test "SlidingWindow two pages no match across boundary with newline" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "hello, world"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("hell"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\no, world!"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + + // Add both pages + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node.next.?); + + // Search should NOT find a match + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // We shouldn't prune because we don't have enough space + try testing.expectEqual(2, w.meta.len()); +} + +test "SlidingWindow two pages no match across boundary with newline reverse" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "hello, world"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("hell"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\no, world!"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + + // Add both pages in reverse order + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node.next.?); + _ = try w.append(node); + + // Search should NOT find a match + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); +} + +test "SlidingWindow two pages no match prunes first page" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "nope!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("boo!"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\n"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + try s.testWriteString("hello. boo!"); + + // Add both pages + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node.next.?); + + // Search should find nothing + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // We should've pruned our page because the second page + // has enough text to contain our needle. + try testing.expectEqual(1, w.meta.len()); +} + +test "SlidingWindow two pages no match keeps both pages" { + const testing = std.testing; + const alloc = testing.allocator; + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("boo!"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\n"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + try s.testWriteString("hello. boo!"); + + // Imaginary needle for search. Doesn't match! + var needle_list: std.ArrayList(u8) = .empty; + defer needle_list.deinit(alloc); + try needle_list.appendNTimes(alloc, 'x', first_page_rows * s.pages.cols); + const needle: []const u8 = needle_list.items; + + var w: SlidingWindow = try .init(alloc, .forward, needle); + defer w.deinit(); + + // Add both pages + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node.next.?); + + // Search should find nothing + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // No pruning because both pages are needed to fit needle. + try testing.expectEqual(2, w.meta.len()); +} + +test "SlidingWindow single append across circular buffer boundary" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "abc"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("XXXXXXXXXXXXXXXXXXXboo!XXXXX"); + + // We are trying to break a circular buffer boundary so the way we + // do this is to duplicate the data then do a failing search. This + // will cause the first page to be pruned. The next time we append we'll + // put it in the middle of the circ buffer. We assert this so that if + // our implementation changes our test will fail. + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node); + { + // No wrap around yet + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len == 0); + } + + // Search non-match, prunes page + try testing.expect(w.next() == null); + try testing.expectEqual(1, w.meta.len()); + + // Change the needle, just needs to be the same length (not a real API) + w.testChangeNeedle("boo"); + + // Add new page, now wraps + _ = try w.append(node); + { + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len > 0); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 19, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 21, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); +} + +test "SlidingWindow single append match on boundary" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .forward, "abcd"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("o!XXXXXXXXXXXXXXXXXXXbo"); + + // We need to surgically modify the last row to be soft-wrapped + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + node.data.getRow(node.data.size.rows - 1).wrap = true; + + // We are trying to break a circular buffer boundary so the way we + // do this is to duplicate the data then do a failing search. This + // will cause the first page to be pruned. The next time we append we'll + // put it in the middle of the circ buffer. We assert this so that if + // our implementation changes our test will fail. + _ = try w.append(node); + _ = try w.append(node); + { + // No wrap around yet + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len == 0); + } + + // Search non-match, prunes page + try testing.expect(w.next() == null); + try testing.expectEqual(1, w.meta.len()); + + // Change the needle, just needs to be the same length (not a real API) + w.testChangeNeedle("boo!"); + + // Add new page, now wraps + _ = try w.append(node); + { + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len > 0); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 21, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 1, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); +} + +test "SlidingWindow single append reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "boo!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("hello. boo! hello. boo!"); + + // We want to test single-page cases. + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + + // We should be able to find two matches. + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 19, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 22, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 7, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 10, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); +} + +test "SlidingWindow single append no match reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "nope!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("hello. boo! hello. boo!"); + + // We want to test single-page cases. + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + + // No matches + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // Should still keep the page + try testing.expectEqual(1, w.meta.len()); +} + +test "SlidingWindow two pages reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "boo!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("boo!"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\n"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + try s.testWriteString("hello. boo!"); + + // Add both pages in reverse order + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node.next.?); + _ = try w.append(node); + + // Search should find two matches (in reverse order) + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 7, + .y = 23, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 10, + .y = 23, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 76, + .y = 22, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 79, + .y = 22, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); +} + +test "SlidingWindow two pages match across boundary reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "hello, world"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "hell" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("hell"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("o, world!"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + + // Add both pages in reverse order + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node.next.?); + _ = try w.append(node); + + // Search should find a match + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 76, + .y = 22, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 7, + .y = 23, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // In reverse mode, the last appended meta (first original page) is large + // enough to contain needle.len - 1 bytes, so pruning occurs + try testing.expectEqual(1, w.meta.len()); +} + +test "SlidingWindow two pages no match prunes first page reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "nope!"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("boo!"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\n"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + try s.testWriteString("hello. boo!"); + + // Add both pages in reverse order + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node.next.?); + _ = try w.append(node); + + // Search should find nothing + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // We should've pruned our page because the second page + // has enough text to contain our needle. + try testing.expectEqual(1, w.meta.len()); +} + +test "SlidingWindow two pages no match keeps both pages reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 1000 }); + defer s.deinit(); + + // Fill up the first page. The final bytes in the first page + // are "boo!" + const first_page_rows = s.pages.pages.first.?.data.capacity.rows; + for (0..first_page_rows - 1) |_| try s.testWriteString("\n"); + for (0..s.pages.cols - 4) |_| try s.testWriteString("x"); + try s.testWriteString("boo!"); + try testing.expect(s.pages.pages.first == s.pages.pages.last); + try s.testWriteString("\n"); + try testing.expect(s.pages.pages.first != s.pages.pages.last); + try s.testWriteString("hello. boo!"); + + // Imaginary needle for search. Doesn't match! + var needle_list: std.ArrayList(u8) = .empty; + defer needle_list.deinit(alloc); + try needle_list.appendNTimes(alloc, 'x', first_page_rows * s.pages.cols); + const needle: []const u8 = needle_list.items; + + var w: SlidingWindow = try .init(alloc, .reverse, needle); + defer w.deinit(); + + // Add both pages in reverse order + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node.next.?); + _ = try w.append(node); + + // Search should find nothing + try testing.expect(w.next() == null); + try testing.expect(w.next() == null); + + // No pruning because both pages are needed to fit needle. + try testing.expectEqual(2, w.meta.len()); +} + +test "SlidingWindow single append across circular buffer boundary reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "abc"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("XXXXXXXXXXXXXXXXXXXboo!XXXXX"); + + // We are trying to break a circular buffer boundary so the way we + // do this is to duplicate the data then do a failing search. This + // will cause the first page to be pruned. The next time we append we'll + // put it in the middle of the circ buffer. We assert this so that if + // our implementation changes our test will fail. + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + _ = try w.append(node); + _ = try w.append(node); + { + // No wrap around yet + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len == 0); + } + + // Search non-match, prunes page + try testing.expect(w.next() == null); + try testing.expectEqual(1, w.meta.len()); + + // Change the needle, just needs to be the same length (not a real API) + // testChangeNeedle doesn't reverse, so pass reversed needle for reverse mode + w.testChangeNeedle("oob"); + + // Add new page, now wraps + _ = try w.append(node); + { + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len > 0); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 19, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 21, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); +} + +test "SlidingWindow single append match on boundary reversed" { + const testing = std.testing; + const alloc = testing.allocator; + + var w: SlidingWindow = try .init(alloc, .reverse, "abcd"); + defer w.deinit(); + + var s = try Screen.init(alloc, .{ .cols = 80, .rows = 24, .max_scrollback = 0 }); + defer s.deinit(); + try s.testWriteString("o!XXXXXXXXXXXXXXXXXXXbo"); + + // We need to surgically modify the last row to be soft-wrapped + try testing.expect(s.pages.pages.first == s.pages.pages.last); + const node: *PageList.List.Node = s.pages.pages.first.?; + node.data.getRow(node.data.size.rows - 1).wrap = true; + + // We are trying to break a circular buffer boundary so the way we + // do this is to duplicate the data then do a failing search. This + // will cause the first page to be pruned. The next time we append we'll + // put it in the middle of the circ buffer. We assert this so that if + // our implementation changes our test will fail. + _ = try w.append(node); + _ = try w.append(node); + { + // No wrap around yet + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len == 0); + } + + // Search non-match, prunes page + try testing.expect(w.next() == null); + try testing.expectEqual(1, w.meta.len()); + + // Change the needle, just needs to be the same length (not a real API) + // testChangeNeedle doesn't reverse, so pass reversed needle for reverse mode + w.testChangeNeedle("!oob"); + + // Add new page, now wraps + _ = try w.append(node); + { + const slices = w.data.getPtrSlice(0, w.data.len()); + try testing.expect(slices[0].len > 0); + try testing.expect(slices[1].len > 0); + } + { + const h = w.next().?; + const sel = h.untracked(); + try testing.expectEqual(point.Point{ .active = .{ + .x = 21, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.start).?); + try testing.expectEqual(point.Point{ .active = .{ + .x = 1, + .y = 0, + } }, s.pages.pointFromPin(.active, sel.end).?); + } + try testing.expect(w.next() == null); +}