1 files changed, 5 insertions, 64 deletions

diff --git a/src/syntax.zig b/src/syntax.zig
index e637bf67..5c8b9c0f 100644
--- a/src/syntax.zig
+++ b/src/syntax.zig
@@ -3,6 +3,7 @@ const config = @import("pardes_config");
 const tracy = @import("tracy.zig");
 const grammar_manifest = @import("grammar_manifest.zig");
 const look = @import("look.zig");
+const c_heap = @import("c_heap");
 
 pub const enabled = config.syntax_highlighting;
 const zig_grammar = config.syntax_zig_grammar;
@@ -139,8 +140,10 @@ fn initSpecs() [specCount()]Spec {
 
 var specs = initSpecs();
 
-const allocation_header_size = 16;
+/// What the tree-sitter runtime allocates from: `start`'s allocator, through
+/// the shared C heap.
 var syntax_allocator: std.mem.Allocator = undefined;
+const syntax_heap = c_heap.Heap(&syntax_allocator);
 var syntax_started = false;
 
 extern fn ts_set_allocator(
@@ -150,56 +153,13 @@ extern fn ts_set_allocator(
     new_free: ?*const fn (ptr: ?*anyopaque) callconv(.c) void,
 ) void;
 
-fn syntaxAlloc(size_arg: usize) callconv(.c) ?*anyopaque {
-    const size = @max(size_arg, 1);
-    const total = std.math.add(usize, allocation_header_size, size) catch return null;
-    const bytes = syntax_allocator.alignedAlloc(u8, .@"16", total) catch return null;
-    const header: *align(16) usize = @ptrCast(bytes.ptr);
-    header.* = total;
-    return @ptrCast(bytes.ptr + allocation_header_size);
-}
-
-fn syntaxCalloc(count: usize, size: usize) callconv(.c) ?*anyopaque {
-    const len = std.math.mul(usize, count, size) catch return null;
-    const pointer = syntaxAlloc(len) orelse return null;
-    const bytes: [*]u8 = @ptrCast(pointer);
-    @memset(bytes[0..len], 0);
-    return pointer;
-}
-
-fn syntaxRealloc(ptr: ?*anyopaque, new_size: usize) callconv(.c) ?*anyopaque {
-    const pointer = ptr orelse return syntaxAlloc(new_size);
-    if (new_size == 0) {
-        syntaxFree(pointer);
-        return null;
-    }
-    const user: [*]u8 = @ptrCast(pointer);
-    const header: *align(16) usize = @ptrCast(@alignCast(user - allocation_header_size));
-    const old_total = header.*;
-    const old_bytes: []align(16) u8 = @as([*]align(16) u8, @ptrCast(header))[0..old_total];
-    const new_total = std.math.add(usize, allocation_header_size, new_size) catch return null;
-    const new_bytes = syntax_allocator.realloc(old_bytes, new_total) catch return null;
-    const new_header: *align(16) usize = @ptrCast(new_bytes.ptr);
-    new_header.* = new_total;
-    return @ptrCast(new_bytes.ptr + allocation_header_size);
-}
-
-fn syntaxFree(ptr: ?*anyopaque) callconv(.c) void {
-    const pointer = ptr orelse return;
-    const user: [*]u8 = @ptrCast(pointer);
-    const header: *align(16) usize = @ptrCast(@alignCast(user - allocation_header_size));
-    const total = header.*;
-    const bytes: []align(16) u8 = @as([*]align(16) u8, @ptrCast(header))[0..total];
-    syntax_allocator.free(bytes);
-}
-
 pub fn start(gpa: std.mem.Allocator) void {
     if (comptime enabled) {
         std.debug.assert(!syntax_started);
         stop();
         syntax_allocator = gpa;
         syntax_started = true;
-        ts_set_allocator(syntaxAlloc, syntaxCalloc, syntaxRealloc, syntaxFree);
+        ts_set_allocator(syntax_heap.malloc, syntax_heap.calloc, syntax_heap.realloc, syntax_heap.free);
     }
 }
 
@@ -935,25 +895,6 @@ test "syntax codeAfterLocation takes whole-token locations and nothing else" {
     try std.testing.expect(codeAfterLocation("   leading space") == null);
 }
 
-test "syntax tree-sitter allocator callbacks preserve and free exact allocations" {
-    syntax_allocator = std.testing.allocator;
-    defer syntax_allocator = undefined;
-
-    var live: ?*anyopaque = syntaxCalloc(4, 1) orelse return error.OutOfMemory;
-    defer if (live) |pointer| syntaxFree(pointer);
-    const original: [*]u8 = @ptrCast(live.?);
-    try std.testing.expectEqualSlices(u8, &.{ 0, 0, 0, 0 }, original[0..4]);
-    @memcpy(original[0..4], "data");
-
-    live = syntaxRealloc(live, 32) orelse return error.OutOfMemory;
-    const grown: [*]u8 = @ptrCast(live.?);
-    try std.testing.expectEqualSlices(u8, "data", grown[0..4]);
-
-    try std.testing.expect(syntaxCalloc(std.math.maxInt(usize), 2) == null);
-    try std.testing.expect(syntaxRealloc(live, 0) == null);
-    live = null;
-}
-
 test "syntax default full grammar set highlights Typst source" {
     if (!enabled or !full_grammars) return;
     start(std.testing.allocator);