1 files changed, 12 insertions, 44 deletions
diff --git a/src/gui/gui.zig b/src/gui/gui.zig
index dd74ae58..73f17a22 100644
--- a/src/gui/gui.zig
+++ b/src/gui/gui.zig
@@ -15,6 +15,7 @@ const crt = @import("crt.zig");
 const pet = @import("pet.zig");
 const fonts = @import("../fonts.zig"); // the Font builtin's half of the seam
 const selection_pipe = @import("../selection_pipe.zig");
+const c_heap = @import("c_heap");
 
 const ninep_io = @import("../9p_io.zig");
 
@@ -133,53 +134,20 @@ fn taglineRaster(font: *c.UIFont, body_px: f32, body_cell_w: u32, body_cell_h: u
         .height = @intCast(band_h),
     };
 }
-/// What FreeType and HarfBuzz allocate from, through ui_malloc and friends
-/// below. runNative points it at the gui's gpa once HarfBuzz's process-wide
-/// objects exist (ui_font_prime), so a Debug build's leak report is about
-/// fonts; a test that counts what fonts leak points it at
-/// std.testing.allocator the same way. Only the render thread calls into
+/// What FreeType and HarfBuzz allocate from, through ui_malloc and friends:
+/// the shared C heap, exported under the names font.c and HarfBuzz's
+/// hb_malloc_impl expect. runNative points it at the gui's gpa once
+/// HarfBuzz's process-wide objects exist (ui_font_prime), so a Debug build's
+/// leak report is about fonts; a test that counts what fonts leak points it
+/// at std.testing.allocator the same way. Only the render thread calls into
 /// fonts, and every allocator it is pointed at is thread-safe anyway.
 var font_allocator: std.mem.Allocator = std.heap.smp_allocator;
-
-/// C's free and realloc pass no size, so a block starts with its size and the
-/// allocator that made it: a block made before font_allocator was repointed
-/// goes back where it came from. 32 bytes keep the caller's pointer 16-byte
-/// (max_align_t) aligned.
-const FontBlock = struct { size: usize, allocator: std.mem.Allocator };
-const font_block_header = 32;
+const font_heap = c_heap.Heap(&font_allocator);
 comptime {
-    std.debug.assert(@sizeOf(FontBlock) <= font_block_header);
-}
-
-export fn ui_malloc(size: usize) ?*anyopaque {
-    const total = std.math.add(usize, font_block_header, size) catch return null;
-    const bytes = font_allocator.alignedAlloc(u8, .@"16", total) catch return null;
-    @as(*FontBlock, @ptrCast(bytes.ptr)).* = .{ .size = size, .allocator = font_allocator };
-    return bytes.ptr + font_block_header;
-}
-
-export fn ui_calloc(count: usize, size: usize) ?*anyopaque {
-    const total = std.math.mul(usize, count, size) catch return null;
-    const block: [*]u8 = @ptrCast(ui_malloc(total) orelse return null);
-    @memset(block[0..total], 0);
-    return block;
-}
-
-export fn ui_realloc(block: ?*anyopaque, size: usize) ?*anyopaque {
-    const old = block orelse return ui_malloc(size);
-    const base: [*]align(16) u8 = @alignCast(@as([*]u8, @ptrCast(old)) - font_block_header);
-    const header: *FontBlock = @ptrCast(base);
-    const total = std.math.add(usize, font_block_header, size) catch return null;
-    const bytes = header.allocator.realloc(base[0 .. font_block_header + header.size], total) catch return null;
-    @as(*FontBlock, @ptrCast(bytes.ptr)).size = size;
-    return bytes.ptr + font_block_header;
-}
-
-export fn ui_free(block: ?*anyopaque) void {
-    const old = block orelse return;
-    const base: [*]align(16) u8 = @alignCast(@as([*]u8, @ptrCast(old)) - font_block_header);
-    const header: *FontBlock = @ptrCast(base);
-    header.allocator.free(base[0 .. font_block_header + header.size]);
+    @export(&font_heap.malloc, .{ .name = "ui_malloc" });
+    @export(&font_heap.calloc, .{ .name = "ui_calloc" });
+    @export(&font_heap.realloc, .{ .name = "ui_realloc" });
+    @export(&font_heap.free, .{ .name = "ui_free" });
 }
 
 test "FreeType and HarfBuzz allocate from the gui allocator and give it all back" {