51 lines
2.0 KiB
Zig
51 lines
2.0 KiB
Zig
const std = @import("../std.zig");
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/// This allocator is used in front of another allocator and counts the numbers of allocs and frees.
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/// The test runner asserts every alloc has a corresponding free at the end of each test.
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///
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/// The detection algorithm is incredibly primitive and only accounts for number of calls.
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/// This should be replaced by the general purpose debug allocator.
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pub const LeakCountAllocator = struct {
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count: usize,
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allocator: std.mem.Allocator,
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internal_allocator: *std.mem.Allocator,
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pub fn init(allocator: *std.mem.Allocator) LeakCountAllocator {
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return .{
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.count = 0,
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.allocator = .{
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.reallocFn = realloc,
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.shrinkFn = shrink,
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},
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.internal_allocator = allocator,
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};
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}
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fn realloc(allocator: *std.mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
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const self = @fieldParentPtr(LeakCountAllocator, "allocator", allocator);
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var data = try self.internal_allocator.reallocFn(self.internal_allocator, old_mem, old_align, new_size, new_align);
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if (old_mem.len == 0) {
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self.count += 1;
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}
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return data;
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}
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fn shrink(allocator: *std.mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
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const self = @fieldParentPtr(LeakCountAllocator, "allocator", allocator);
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if (new_size == 0) {
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if (self.count == 0) {
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std.debug.panic("error - too many calls to free, most likely double free", .{});
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}
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self.count -= 1;
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}
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return self.internal_allocator.shrinkFn(self.internal_allocator, old_mem, old_align, new_size, new_align);
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}
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pub fn validate(self: LeakCountAllocator) !void {
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if (self.count > 0) {
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std.debug.warn("error - detected leaked allocations without matching free: {}\n", .{self.count});
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return error.Leak;
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}
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}
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};
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