alloc_observe.buffer

1const std = @import("std");2const adapter = @import("allocator.zig");3const protocol = @import("protocol.zig");45/// A buffer-first allocator type that manages allocations from an initial6/// caller-provided buffer before falling back to a secondary allocator. In7/// disabled builds, this type aliases `std.heap.BufferFirstAllocator`. In8/// enabled builds, it wraps that allocator and exposes only `init` and9/// `allocator`, forwarding allocation calls through an internal10/// `ObservedAllocator` tagged with the `buffer_first` producer kind. The11/// wrapper acts solely as an allocator adapter and adds no lifecycle records.12pub const First = if (protocol.enabled)13    ObservedFirst14else15    std.heap.BufferFirstAllocator;1617const ObservedFirst = struct {18    inner: std.heap.BufferFirstAllocator,19    observed: adapter.ObservedAllocator = undefined,20    producer_id: u64,2122    const Self = @This();2324    /// Initializes the buffer-first allocator by passing the caller-supplied25    /// initial buffer slice and fallback allocator to the underlying26    /// implementation, assigning a unique producer identifier when observation27    /// is enabled. The allocator borrows the buffer without copying or taking28    /// ownership of it. Callers must ensure that both the initial memory buffer29    /// and the fallback allocator remain valid and stable for the entire30    /// operational lifetime of the instance.31    pub fn init(buffer: []u8, fallback: std.mem.Allocator) Self {32        return .{33            .inner = std.heap.BufferFirstAllocator.init(buffer, fallback),34            .producer_id = protocol.producerId(),35        };36    }3738    /// Returns a borrowed allocator handle backed by the stable instance. In39    /// enabled builds, this call initializes an embedded adapter pointing to40    /// the underlying buffer-first allocator. The method offers no41    /// thread-safety guarantees for concurrent calls on the same instance, so42    /// callers must serialize access or complete handle creation before43    /// sharing.44    pub fn allocator(self: *Self) std.mem.Allocator {45        self.observed = adapter.ObservedAllocator.init(46            self.inner.allocator(),47            self.producer_id,48            .buffer_first,49        );50        return self.observed.allocator();51    }52};

1pub const buffer = @import("buffer.zig");