diff --git a/include/ghostty/vt/allocator.h b/include/ghostty/vt/allocator.h index f1406cf79..ed2d36794 100644 --- a/include/ghostty/vt/allocator.h +++ b/include/ghostty/vt/allocator.h @@ -44,6 +44,24 @@ * 2. Create a GhosttyAllocator struct with your vtable and context * 3. Pass the allocator to functions that accept one * + * ## Alloc/Free Helpers + * + * ghostty_alloc() and ghostty_free() provide a simple malloc/free-style + * interface for allocating and freeing byte buffers through the library's + * allocator. These are useful when: + * + * - You need to allocate a buffer to pass into a libghostty-vt function + * (e.g. preparing input data for ghostty_terminal_vt_write()). + * - You need to free a buffer returned by a libghostty-vt function + * (e.g. the output of ghostty_formatter_format_alloc()). + * - You are on a platform where the library's internal allocator differs + * from the consumer's C runtime (e.g. Windows, where Zig's libc and + * MSVC's CRT maintain separate heaps), so calling the standard C + * free() on library-allocated memory would be undefined behavior. + * + * Always use the same allocator (or NULL) for both the allocation and + * the corresponding free. + * * @{ */ @@ -191,6 +209,21 @@ typedef struct GhosttyAllocator { const GhosttyAllocatorVtable *vtable; } GhosttyAllocator; +/** + * Allocate a buffer of `len` bytes. + * + * Uses the provided allocator, or the default allocator if NULL is passed. + * The returned buffer must be freed with ghostty_free() using the same + * allocator. + * + * @param allocator Pointer to the allocator to use, or NULL for the default + * @param len Number of bytes to allocate + * @return Pointer to the allocated buffer, or NULL if allocation failed + * + * @ingroup allocator + */ +uint8_t* ghostty_alloc(const GhosttyAllocator* allocator, size_t len); + /** * Free memory that was allocated by a libghostty-vt function. * diff --git a/src/lib_vt.zig b/src/lib_vt.zig index 0452d5e31..8ccd6bf96 100644 --- a/src/lib_vt.zig +++ b/src/lib_vt.zig @@ -218,6 +218,7 @@ comptime { @export(&c.grid_ref_graphemes, .{ .name = "ghostty_grid_ref_graphemes" }); @export(&c.grid_ref_style, .{ .name = "ghostty_grid_ref_style" }); @export(&c.build_info, .{ .name = "ghostty_build_info" }); + @export(&c.alloc_alloc, .{ .name = "ghostty_alloc" }); @export(&c.alloc_free, .{ .name = "ghostty_free" }); // On Wasm we need to export our allocator convenience functions. diff --git a/src/terminal/c/allocator.zig b/src/terminal/c/allocator.zig index b16cf5d25..f16c7237f 100644 --- a/src/terminal/c/allocator.zig +++ b/src/terminal/c/allocator.zig @@ -3,6 +3,20 @@ const testing = std.testing; const lib_alloc = @import("../../lib/allocator.zig"); const CAllocator = lib_alloc.Allocator; +/// Allocate a buffer of `len` bytes using the given allocator +/// (or the default allocator if NULL). +/// +/// Returns a pointer to the allocated buffer, or NULL if the +/// allocation failed. +pub fn alloc( + alloc_: ?*const CAllocator, + len: usize, +) callconv(.c) ?[*]u8 { + const allocator = lib_alloc.default(alloc_); + const buf = allocator.alloc(u8, len) catch return null; + return buf.ptr; +} + /// Free memory that was allocated by a libghostty-vt function. /// /// This must be used to free buffers returned by functions like @@ -14,8 +28,25 @@ pub fn free( len: usize, ) callconv(.c) void { const mem = ptr orelse return; - const alloc = lib_alloc.default(alloc_); - alloc.free(mem[0..len]); + const allocator = lib_alloc.default(alloc_); + allocator.free(mem[0..len]); +} + +test "alloc returns non-null" { + const ptr = alloc(&lib_alloc.test_allocator, 16); + try testing.expect(ptr != null); + free(&lib_alloc.test_allocator, ptr, 16); +} + +test "alloc with null allocator" { + const ptr = alloc(null, 8); + try testing.expect(ptr != null); + free(null, ptr, 8); +} + +test "alloc zero length" { + const ptr = alloc(&lib_alloc.test_allocator, 0); + defer free(&lib_alloc.test_allocator, ptr, 0); } test "free null pointer" { @@ -23,14 +54,14 @@ test "free null pointer" { } test "free allocated memory" { - const alloc = lib_alloc.default(&lib_alloc.test_allocator); - const mem = try alloc.alloc(u8, 16); + const allocator = lib_alloc.default(&lib_alloc.test_allocator); + const mem = try allocator.alloc(u8, 16); free(&lib_alloc.test_allocator, mem.ptr, mem.len); } test "free with null allocator" { // null allocator falls back to the default (test allocator in tests) - const alloc = lib_alloc.default(null); - const mem = try alloc.alloc(u8, 8); + const allocator = lib_alloc.default(null); + const mem = try allocator.alloc(u8, 8); free(null, mem.ptr, mem.len); } diff --git a/src/terminal/c/main.zig b/src/terminal/c/main.zig index 8e6674049..7597228d1 100644 --- a/src/terminal/c/main.zig +++ b/src/terminal/c/main.zig @@ -116,6 +116,7 @@ pub const mouse_encoder_encode = mouse_encode.encode; pub const paste_is_safe = paste.is_safe; +pub const alloc_alloc = allocator.alloc; pub const alloc_free = allocator.free; pub const size_report_encode = size_report.encode;