Commit ea516f0e81d055e0d7504eff36dfde694831bec1 | zig

author	Andrew Kelley <andrew@ziglang.org> 2025-02-25 17:58:57-08:00
committer	Andrew Kelley <andrew@ziglang.org> 2025-02-26 11:42:04-08:00
log	ea516f0e81d055e0d7504eff36dfde694831bec1
tree	753b46f26c09e1dfc435c9d7e976b41e477bf777
parent	0fc7c9f57c0042cfe6dab9deb3b5fe2f9404d744

bump package id component to 32 bits

and to make the base64 round even, bump sha256 to 200 bits (up from 192)

4 files changed, 26 insertions(+), 27 deletions(-)

build.zig.zon
doc
- build.zig.zon.md
src
- Package.zig
- Package
  - Manifest.zig

build.zig.zon+1-1

...	...	@@ -12,5 +12,5 @@
12	12	},
13	13	},
14	14	.paths = .{""},
15		.nonce = 0xc1ce10810000f013,
	15	.nonce = 0xc1ce108124179e16,
16	16	}

doc/build.zig.zon.md+7-5

...	...	@@ -22,9 +22,11 @@ Zig package namespace.
22	22
23	23	Must be a valid bare Zig identifier (don't `@` me), limited to 32 bytes.
24	24
	25	Together with `nonce`, this represents a globally unique package identifier.
	26
25	27	### `nonce`
26	28
27		Together with name, this represents a globally unique package identifier. This
	29	Together with `name`, this represents a globally unique package identifier. This
28	30	field is auto-initialized by the toolchain when the package is first created,
29	31	and then never changes. This allows Zig to unambiguously detect when one
30	32	package is an updated version of another.
...	...	@@ -34,14 +36,14 @@ project is still maintained. Otherwise, the fork is hostile, attempting to
34	36	take control over the original project's identity. The nonce can be regenerated
35	37	by deleting the field and running `zig build`.
36	38
37		This 64-bit integer is the combination of a 16-bit id component, a 32-bit
38		checksum, and 16 bits of reserved zeroes.
	39	This 64-bit integer is the combination of a 32-bit id component and a 32-bit
	40	checksum.
39	41
40	42	The id component within the nonce has these restrictions:
41	43
42		`0x0000` is reserved for legacy packages.
	44	`0x00000000` is reserved for legacy packages.
43	45
44		`0xffff` is reserved to represent "naked" packages.
	46	`0xffffffff` is reserved to represent "naked" packages.
45	47
46	48	The checksum is computed from `name` and serves to protect Zig users from
47	49	accidental id collisions.

src/Package.zig+16-19

...	...	@@ -11,20 +11,19 @@ pub const multihash_hex_digest_len = 2 * multihash_len;
11	11	pub const MultiHashHexDigest = [multihash_hex_digest_len]u8;
12	12
13	13	pub const Nonce = packed struct(u64) {
14		id: u16,
15		reserved: u16 = 0,
	14	id: u32,
16	15	checksum: u32,
17	16
18	17	pub fn generate(name: []const u8) Nonce {
19	18	return .{
20		.id = std.crypto.random.intRangeLessThan(u16, 0x0001, 0xffff),
	19	.id = std.crypto.random.intRangeLessThan(u32, 1, 0xffffffff),
21	20	.checksum = std.hash.Crc32.hash(name),
22	21	};
23	22	}
24	23
25	24	pub fn validate(n: Nonce, name: []const u8) bool {
26	25	switch (n.id) {
27		0x0000, 0xffff => return false,
	26	0x00000000, 0xffffffff => return false,
28	27	else => return std.hash.Crc32.hash(name) == n.checksum,
29	28	}
30	29	}
...	...	@@ -54,8 +53,8 @@ pub const Hash = struct {
54	53	pub const Algo = std.crypto.hash.sha2.Sha256;
55	54	pub const Digest = [Algo.digest_length]u8;
56	55
57		/// Example: "nnnn-vvvv-hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh"
58		pub const max_len = 32 + 1 + 32 + 1 + (16 + 32 + 192) / 6;
	56	/// Example: "nnnn-vvvv-hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh"
	57	pub const max_len = 32 + 1 + 32 + 1 + (32 + 32 + 200) / 6;
59	58
60	59	pub fn fromSlice(s: []const u8) Hash {
61	60	assert(s.len <= max_len);
...	...	@@ -96,14 +95,12 @@ pub const Hash = struct {
96	95	/// bytes and assumed be a valid zig identifier
97	96	/// * semver is the version field from build.zig.zon, asserted to be at
98	97	/// most 32 bytes
99		/// * hashplus is the following 39-byte array, base64 encoded using -_ to make
	98	/// * hashplus is the following 33-byte array, base64 encoded using -_ to make
100	99	/// it filesystem safe:
101		/// - (2 bytes) LE u16 Package ID
	100	/// - (4 bytes) LE u32 Package ID
102	101	/// - (4 bytes) LE u32 total decompressed size in bytes, overflow saturated
103		/// - (24 bytes) truncated SHA-256 digest of hashed files of the package
104		///
105		/// example: "nasm-2.16.1-3-AAD_ZlwACpGU-c3QXp_yNyn07Q5U9Rq-Cb1ur2G1"
106		pub fn init(digest: Digest, name: []const u8, ver: []const u8, id: u16, size: u32) Hash {
	102	/// - (25 bytes) truncated SHA-256 digest of hashed files of the package
	103	pub fn init(digest: Digest, name: []const u8, ver: []const u8, id: u32, size: u32) Hash {
107	104	assert(name.len <= 32);
108	105	assert(ver.len <= 32);
109	106	var result: Hash = undefined;
...	...	@@ -112,11 +109,11 @@ pub const Hash = struct {
112	109	buf.appendAssumeCapacity('-');
113	110	buf.appendSliceAssumeCapacity(ver);
114	111	buf.appendAssumeCapacity('-');
115		var hashplus: [30]u8 = undefined;
116		std.mem.writeInt(u16, hashplus[0..2], id, .little);
117		std.mem.writeInt(u32, hashplus[2..6], size, .little);
118		hashplus[6..].* = digest[0..24].*;
119		_ = std.base64.url_safe_no_pad.Encoder.encode(buf.addManyAsArrayAssumeCapacity(40), &hashplus);
	112	var hashplus: [33]u8 = undefined;
	113	std.mem.writeInt(u32, hashplus[0..4], id, .little);
	114	std.mem.writeInt(u32, hashplus[4..8], size, .little);
	115	hashplus[8..].* = digest[0..25].*;
	116	_ = std.base64.url_safe_no_pad.Encoder.encode(buf.addManyAsArrayAssumeCapacity(44), &hashplus);
120	117	@memset(buf.unusedCapacitySlice(), 0);
121	118	return result;
122	119	}
...	...	@@ -194,8 +191,8 @@ test Hash {
194	191	0xc7, 0xf5, 0x71, 0xb7, 0xb4, 0xe7, 0x6f, 0x3c, 0xdb, 0x87, 0x7a, 0x7f, 0xdd, 0xf9, 0x77, 0x87,
195	192	0x9d, 0xd3, 0x86, 0xfa, 0x73, 0x57, 0x9a, 0xf7, 0x9d, 0x1e, 0xdb, 0x8f, 0x3a, 0xd9, 0xbd, 0x9f,
196	193	};
197		const result: Hash = .init(example_digest, "nasm", "2.16.1-2", 0xcafe, 10 * 1024 * 1024);
198		try std.testing.expectEqualStrings("nasm-2.16.1-2-_soAAKAAx_Vxt7Tnbzzbh3p_3fl3h53ThvpzV5r3", result.toSlice());
	194	const result: Hash = .init(example_digest, "nasm", "2.16.1-3", 0xcafebabe, 10 * 1024 * 1024);
	195	try std.testing.expectEqualStrings("nasm-2.16.1-3-vrr-ygAAoADH9XG3tOdvPNuHen_d-XeHndOG-nNXmved", result.toSlice());
199	196	}
200	197
201	198	test {

src/Package/Manifest.zig+2-2

...	...	@@ -36,7 +36,7 @@ pub const ErrorMessage = struct {
36	36	};
37	37
38	38	name: []const u8,
39		id: u16,
	39	id: u32,
40	40	version: std.SemanticVersion,
41	41	version_node: Ast.Node.Index,
42	42	dependencies: std.StringArrayHashMapUnmanaged(Dependency),
...	...	@@ -149,7 +149,7 @@ const Parse = struct {
149	149	errors: std.ArrayListUnmanaged(ErrorMessage),
150	150
151	151	name: []const u8,
152		id: u16,
	152	id: u32,
153	153	version: std.SemanticVersion,
154	154	version_node: Ast.Node.Index,
155	155	dependencies: std.StringArrayHashMapUnmanaged(Dependency),