1 files changed, 161 insertions, 0 deletions
diff --git a/vendor/libghostty-vt/src/benchmark/TerminalStream.zig b/vendor/libghostty-vt/src/benchmark/TerminalStream.zig
new file mode 100644
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+++ b/vendor/libghostty-vt/src/benchmark/TerminalStream.zig
@@ -0,0 +1,161 @@
+//! This benchmark tests the performance of the terminal stream
+//! handler from input to terminal state update. This is useful to
+//! test general throughput of VT parsing and handling.
+//!
+//! Note that the handler used for this benchmark isn't the full
+//! terminal handler, since that requires a significant amount of
+//! state. This is a simplified version that only handles specific
+//! terminal operations like printing characters. We should expand
+//! this to include more operations to improve the accuracy of the
+//! benchmark.
+//!
+//! It is a fairly broad benchmark that can be used to determine
+//! if we need to optimize something more specific (e.g. the parser).
+const TerminalStream = @This();
+
+const std = @import("std");
+const assert = std.debug.assert;
+const Allocator = std.mem.Allocator;
+const terminalpkg = @import("../terminal/main.zig");
+const Benchmark = @import("Benchmark.zig");
+const options = @import("options.zig");
+const Terminal = terminalpkg.Terminal;
+const Stream = terminalpkg.Stream(*Handler);
+
+const log = std.log.scoped(.@"terminal-stream-bench");
+
+opts: Options,
+terminal: Terminal,
+handler: Handler,
+stream: Stream,
+
+/// The file, opened in the setup function.
+data_f: ?std.fs.File = null,
+
+pub const Options = struct {
+    /// The size of the terminal. This affects benchmarking when
+    /// dealing with soft line wrapping and the memory impact
+    /// of page sizes.
+    @"terminal-rows": u16 = 80,
+    @"terminal-cols": u16 = 120,
+
+    /// The data to read as a filepath. If this is "-" then
+    /// we will read stdin. If this is unset, then we will
+    /// do nothing (benchmark is a noop). It'd be more unixy to
+    /// use stdin by default but I find that a hanging CLI command
+    /// with no interaction is a bit annoying.
+    data: ?[]const u8 = null,
+};
+
+/// Create a new terminal stream handler for the given arguments.
+pub fn create(
+    alloc: Allocator,
+    opts: Options,
+) !*TerminalStream {
+    const ptr = try alloc.create(TerminalStream);
+    errdefer alloc.destroy(ptr);
+
+    ptr.* = .{
+        .opts = opts,
+        .terminal = try .init(alloc, .{
+            .rows = opts.@"terminal-rows",
+            .cols = opts.@"terminal-cols",
+        }),
+        .handler = .{ .t = &ptr.terminal },
+        .stream = .init(&ptr.handler),
+    };
+
+    return ptr;
+}
+
+pub fn destroy(self: *TerminalStream, alloc: Allocator) void {
+    self.terminal.deinit(alloc);
+    alloc.destroy(self);
+}
+
+pub fn benchmark(self: *TerminalStream) Benchmark {
+    return .init(self, .{
+        .stepFn = step,
+        .setupFn = setup,
+        .teardownFn = teardown,
+    });
+}
+
+fn setup(ptr: *anyopaque) Benchmark.Error!void {
+    const self: *TerminalStream = @ptrCast(@alignCast(ptr));
+
+    // Always reset our terminal state
+    self.terminal.fullReset();
+
+    // Open our data file to prepare for reading. We can do more
+    // validation here eventually.
+    assert(self.data_f == null);
+    self.data_f = options.dataFile(self.opts.data) catch |err| {
+        log.warn("error opening data file err={}", .{err});
+        return error.BenchmarkFailed;
+    };
+}
+
+fn teardown(ptr: *anyopaque) void {
+    const self: *TerminalStream = @ptrCast(@alignCast(ptr));
+    if (self.data_f) |f| {
+        f.close();
+        self.data_f = null;
+    }
+}
+
+fn step(ptr: *anyopaque) Benchmark.Error!void {
+    const self: *TerminalStream = @ptrCast(@alignCast(ptr));
+
+    // Get our buffered reader so we're not predominantly
+    // waiting on file IO. It'd be better to move this fully into
+    // memory. If we're IO bound though that should show up on
+    // the benchmark results and... I know writing this that we
+    // aren't currently IO bound.
+    const f = self.data_f orelse return;
+
+    var read_buf: [4096]u8 align(std.atomic.cache_line) = undefined;
+    var f_reader = f.reader(&read_buf);
+    const r = &f_reader.interface;
+
+    var buf: [4096]u8 = undefined;
+    while (true) {
+        const n = r.readSliceShort(&buf) catch {
+            log.warn("error reading data file err={?}", .{f_reader.err});
+            return error.BenchmarkFailed;
+        };
+        if (n == 0) break; // EOF reached
+        self.stream.nextSlice(buf[0..n]);
+    }
+}
+
+/// Implements the handler interface for the terminal.Stream.
+/// We should expand this to include more operations to make
+/// our benchmark more realistic.
+const Handler = struct {
+    t: *Terminal,
+
+    pub fn vt(
+        self: *Handler,
+        comptime action: Stream.Action.Tag,
+        value: Stream.Action.Value(action),
+    ) void {
+        switch (action) {
+            .print => self.t.print(value.cp) catch |err| {
+                log.warn("error processing benchmark print err={}", .{err});
+            },
+            else => {},
+        }
+    }
+};
+
+test TerminalStream {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    const impl: *TerminalStream = try .create(alloc, .{});
+    defer impl.destroy(alloc);
+
+    const bench = impl.benchmark();
+    _ = try bench.run(.once);
+}