snapdir for Zig

# needs a Rust toolchain + cbindgen; on Alpine also: apk add libgcc
cargo build --release                       # -> libsnapdir_ffi.a
cbindgen --config cbindgen.toml --crate snapdir-ffi --output include/snapdir.h .
zig fetch --save git+https://github.com/snapdir/snapdir#<rev>

const std = @import("std");
const snapdir = @import("snapdir");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const a = gpa.allocator();

    // id → 64-char snapshot id ([64]u8 value, no free).
    const id = try snapdir.id(a, "./my-dir", .{});
    std.debug.print("{s}\n", .{id});

    // Full manifest (raw text + parsed entries); free with deinit.
    var m = try snapdir.manifest(a, "./my-dir", .{});
    defer m.deinit(a);
    for (m.entries) |e| {
        // e.type (PathType), e.perm (u32), e.checksum ([64]u8), e.size (u64), e.path
    }
    // snapdir.idFromManifest(m) == id

    // Options: exclude a regex, do not follow symlinks.
    const filtered = try snapdir.id(a, "./my-dir", .{ .no_follow = true, .exclude = "\\.tmp$" });
    _ = filtered;

    // Transfer to a store (URI is an argument).
    const pushed = try snapdir.push(a, "./my-dir", "file:///…/store", .{});
    try snapdir.pull(a, &pushed, "file:///…/store", "./restored", .{});

    // fetch caches objects locally; diff compares two store contents
    // as STATUS<TAB>PATH entries (A / D / M / =), byte-identical to the CLI.
    const changes = try snapdir.diff(a, "file:///…/store-a", "file:///…/store-b", .{});
    defer {
        for (changes) |c| a.free(c.path);
        a.free(changes);
    }
    for (changes) |c| std.debug.print("{c}\t{s}\n", .{ @intFromEnum(c.status), c.path });
}

const id = snapdir.id(a, "/no/such/path", .{}) catch |err| switch (err) {
    error.IoError => return,       // IO_ERROR       — filesystem / network failure
    error.HashMismatch => return,  // HASH_MISMATCH  — content did not verify
    error.StoreError => return,    // STORE_ERROR    — object store rejected the op
    error.InFlux => return,        // IN_FLUX        — tree changed mid-snapshot
    error.CatalogError => return,  // CATALOG_ERROR  — manifest/catalog problem
    error.InvalidId => return,     // INVALID_ID     — malformed snapshot id
    error.InvalidStore => return,  // INVALID_STORE  — unparseable store URI
    error.Conflict => return,      // CONFLICT       — concurrent write conflict
    else => return err,            // OutOfMemory
};