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zig build system creates symlinks atomically 

* add std.base64
 * add std.os.rename
 * add std.os.atomicSymLink
master
Andrew Kelley 2017-04-17 19:08:41 -04:00
parent 401eed8153
commit 216e14891e
6 changed files with 266 additions and 11 deletions
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1
CMakeLists.txt
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@ -204,6 +204,7 @@ install(TARGETS zig DESTINATION bin)
install(FILES ${C_HEADERS} DESTINATION ${C_HEADERS_DEST})
install(FILES "${CMAKE_SOURCE_DIR}/std/base64.zig" DESTINATION "${ZIG_STD_DEST}")
install(FILES "${CMAKE_SOURCE_DIR}/std/buf_map.zig" DESTINATION "${ZIG_STD_DEST}")
install(FILES "${CMAKE_SOURCE_DIR}/std/buf_set.zig" DESTINATION "${ZIG_STD_DEST}")
install(FILES "${CMAKE_SOURCE_DIR}/std/build.zig" DESTINATION "${ZIG_STD_DEST}")

184
std/base64.zig Normal file
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@ -0,0 +1,184 @@
const assert = @import("debug.zig").assert;
const mem = @import("mem.zig");
pub const standard_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
pub fn encode(dest: []u8, source: []const u8) -> []u8 {
return encodeWithAlphabet(dest, source, standard_alphabet);
}
pub fn decode(dest: []u8, source: []const u8) -> []u8 {
return decodeWithAlphabet(dest, source, standard_alphabet);
}
pub fn encodeWithAlphabet(dest: []u8, source: []const u8, alphabet: []const u8) -> []u8 {
assert(alphabet.len == 65);
assert(dest.len >= calcEncodedSize(source.len));
var i: usize = 0;
var out_index: usize = 0;
while (i + 2 < source.len; i += 3) {
dest[out_index] = alphabet[(source[i] >> 2) & 0x3f];
out_index += 1;
dest[out_index] = alphabet[((source[i] & 0x3) <<% 4) |
((source[i + 1] & 0xf0) >> 4)];
out_index += 1;
dest[out_index] = alphabet[((source[i + 1] & 0xf) <<% 2) |
((source[i + 2] & 0xc0) >> 6)];
out_index += 1;
dest[out_index] = alphabet[source[i + 2] & 0x3f];
out_index += 1;
}
if (i < source.len) {
dest[out_index] = alphabet[(source[i] >> 2) & 0x3f];
out_index += 1;
if (i + 1 == source.len) {
dest[out_index] = alphabet[(source[i] & 0x3) <<% 4];
out_index += 1;
dest[out_index] = alphabet[64];
out_index += 1;
} else {
dest[out_index] = alphabet[((source[i] & 0x3) <<% 4) |
((source[i + 1] & 0xf0) >> 4)];
out_index += 1;
dest[out_index] = alphabet[(source[i + 1] & 0xf) <<% 2];
out_index += 1;
}
dest[out_index] = alphabet[64];
out_index += 1;
}
return dest[0...out_index];
}
pub fn decodeWithAlphabet(dest: []u8, source: []const u8, alphabet: []const u8) -> []u8 {
assert(alphabet.len == 65);
var ascii6 = []u8{64} ** 256;
for (alphabet) |c, i| {
ascii6[c] = u8(i);
}
return decodeWithAscii6BitMap(dest, source, ascii6[0...], alphabet[64]);
}
pub fn decodeWithAscii6BitMap(dest: []u8, source: []const u8, ascii6: []const u8, pad_char: u8) -> []u8 {
assert(ascii6.len == 256);
assert(dest.len >= calcExactDecodedSizeWithPadChar(source, pad_char));
var src_index: usize = 0;
var dest_index: usize = 0;
var in_buf_len: usize = source.len;
while (in_buf_len > 0 and source[in_buf_len - 1] == pad_char) {
in_buf_len -= 1;
}
while (in_buf_len > 4) {
dest[dest_index] = ascii6[source[src_index + 0]] <<% 2 |
ascii6[source[src_index + 1]] >> 4;
dest_index += 1;
dest[dest_index] = ascii6[source[src_index + 1]] <<% 4 |
ascii6[source[src_index + 2]] >> 2;
dest_index += 1;
dest[dest_index] = ascii6[source[src_index + 2]] <<% 6 |
ascii6[source[src_index + 3]];
dest_index += 1;
src_index += 4;
in_buf_len -= 4;
}
if (in_buf_len > 1) {
dest[dest_index] = ascii6[source[src_index + 0]] <<% 2 |
ascii6[source[src_index + 1]] >> 4;
dest_index += 1;
}
if (in_buf_len > 2) {
dest[dest_index] = ascii6[source[src_index + 1]] <<% 4 |
ascii6[source[src_index + 2]] >> 2;
dest_index += 1;
}
if (in_buf_len > 3) {
dest[dest_index] = ascii6[source[src_index + 2]] <<% 6 |
ascii6[source[src_index + 3]];
dest_index += 1;
}
return dest[0...dest_index];
}
pub fn calcEncodedSize(source_len: usize) -> usize {
return (((source_len * 4) / 3 + 3) / 4) * 4;
}
/// Computes the upper bound of the decoded size based only on the encoded length.
/// To compute the exact decoded size, see ::calcExactDecodedSize
pub fn calcMaxDecodedSize(encoded_len: usize) -> usize {
return @divExact(encoded_len * 3, 4);
}
/// Computes the number of decoded bytes there will be. This function must
/// be given the encoded buffer because there might be padding
/// bytes at the end ('=' in the standard alphabet)
pub fn calcExactDecodedSize(encoded: []const u8) -> usize {
return calcExactDecodedSizeWithAlphabet(encoded, standard_alphabet);
}
pub fn calcExactDecodedSizeWithAlphabet(encoded: []const u8, alphabet: []const u8) -> usize {
assert(alphabet.len == 65);
return calcExactDecodedSizeWithPadChar(encoded, alphabet[64]);
}
pub fn calcExactDecodedSizeWithPadChar(encoded: []const u8, pad_char: u8) -> usize {
var buf_len = encoded.len;
while (buf_len > 0 and encoded[buf_len - 1] == pad_char) {
buf_len -= 1;
}
return (buf_len * 3) / 4;
}
test "base64" {
testBase64();
comptime testBase64();
}
fn testBase64() {
testBase64Case("", "");
testBase64Case("f", "Zg==");
testBase64Case("fo", "Zm8=");
testBase64Case("foo", "Zm9v");
testBase64Case("foob", "Zm9vYg==");
testBase64Case("fooba", "Zm9vYmE=");
testBase64Case("foobar", "Zm9vYmFy");
}
fn testBase64Case(expected_decoded: []const u8, expected_encoded: []const u8) {
const calculated_decoded_len = calcExactDecodedSize(expected_encoded);
assert(calculated_decoded_len == expected_decoded.len);
const calculated_encoded_len = calcEncodedSize(expected_decoded.len);
assert(calculated_encoded_len == expected_encoded.len);
var buf: [100]u8 = undefined;
const actual_decoded = decode(buf[0...], expected_encoded);
assert(actual_decoded.len == expected_decoded.len);
assert(mem.eql(u8, expected_decoded, actual_decoded));
const actual_encoded = encode(buf[0...], expected_decoded);
assert(actual_encoded.len == expected_encoded.len);
assert(mem.eql(u8, expected_encoded, actual_encoded));
}

12
std/build.zig
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@ -816,11 +816,9 @@ const CLibrary = struct {
builder.spawnChild(cc, cc_args.toSliceConst());
// sym link for libfoo.so.1 to libfoo.so.1.2.3
_ = os.deleteFile(builder.allocator, self.major_only_filename);
%%os.symLink(builder.allocator, self.out_filename, self.major_only_filename);
%%os.atomicSymLink(builder.allocator, self.out_filename, self.major_only_filename);
// sym link for libfoo.so to libfoo.so.1
_ = os.deleteFile(builder.allocator, self.name_only_filename);
%%os.symLink(builder.allocator, self.major_only_filename, self.name_only_filename);
%%os.atomicSymLink(builder.allocator, self.major_only_filename, self.name_only_filename);
}
}
@ -1029,10 +1027,8 @@ const InstallCLibraryStep = struct {
self.builder.copyFile(self.lib.out_filename, self.dest_file);
if (!self.lib.static) {
_ = os.deleteFile(self.builder.allocator, self.lib.major_only_filename);
%%os.symLink(self.builder.allocator, self.lib.out_filename, self.lib.major_only_filename);
_ = os.deleteFile(self.builder.allocator, self.lib.name_only_filename);
%%os.symLink(self.builder.allocator, self.lib.major_only_filename, self.lib.name_only_filename);
%%os.atomicSymLink(self.builder.allocator, self.lib.out_filename, self.lib.major_only_filename);
%%os.atomicSymLink(self.builder.allocator, self.lib.major_only_filename, self.lib.name_only_filename);
}
}
};

1
std/index.zig
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@ -1,3 +1,4 @@
pub const base64 = @import("base64.zig");
pub const build = @import("build.zig");
pub const c = @import("c/index.zig");
pub const cstr = @import("cstr.zig");

75
std/os/index.zig
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@ -26,6 +26,7 @@ const BufMap = @import("../buf_map.zig").BufMap;
const cstr = @import("../cstr.zig");
const io = @import("../io.zig");
const base64 = @import("../base64.zig");
error Unexpected;
error SystemResources;
@ -35,9 +36,11 @@ error FileSystem;
error IsDir;
error FileNotFound;
error FileBusy;
error LinkPathAlreadyExists;
error PathAlreadyExists;
error SymLinkLoop;
error ReadOnlyFileSystem;
error LinkQuotaExceeded;
error RenameAcrossMountPoints;
/// Fills `buf` with random bytes. If linking against libc, this calls the
/// appropriate OS-specific library call. Otherwise it uses the zig standard
@ -197,7 +200,7 @@ pub fn posixDup2(old_fd: i32, new_fd: i32) -> %void {
if (err > 0) {
return switch (err) {
errno.EBUSY, errno.EINTR => continue,
errno.EMFILE => error.SystemResources,
errno.EMFILE => error.ProcessFdQuotaExceeded,
errno.EINVAL => unreachable,
else => error.Unexpected,
};
@ -406,7 +409,7 @@ pub fn symLink(allocator: &Allocator, existing_path: []const u8, new_path: []con
errno.EFAULT, errno.EINVAL => unreachable,
errno.EACCES, errno.EPERM => error.AccessDenied,
errno.EDQUOT => error.DiskQuota,
errno.EEXIST => error.LinkPathAlreadyExists,
errno.EEXIST => error.PathAlreadyExists,
errno.EIO => error.FileSystem,
errno.ELOOP => error.SymLinkLoop,
errno.ENAMETOOLONG => error.NameTooLong,
@ -419,6 +422,38 @@ pub fn symLink(allocator: &Allocator, existing_path: []const u8, new_path: []con
}
}
// here we replace the standard +/ with -_ so that it can be used in a file name
const b64_fs_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_=";
pub fn atomicSymLink(allocator: &Allocator, existing_path: []const u8, new_path: []const u8) -> %void {
try (symLink(allocator, existing_path, new_path)) {
return;
} else |err| {
if (err != error.PathAlreadyExists) {
return err;
}
}
var rand_buf: [12]u8 = undefined;
const tmp_path = %return allocator.alloc(u8, new_path.len + base64.calcEncodedSize(rand_buf.len));
defer allocator.free(tmp_path);
mem.copy(u8, tmp_path[0...], new_path);
while (true) {
%return getRandomBytes(rand_buf[0...]);
_ = base64.encodeWithAlphabet(tmp_path[new_path.len...], rand_buf, b64_fs_alphabet);
try (symLink(allocator, existing_path, tmp_path)) {
return rename(allocator, tmp_path, new_path);
} else |err| {
if (err == error.PathAlreadyExists) {
continue;
} else {
return err;
}
}
}
}
pub fn deleteFile(allocator: &Allocator, file_path: []const u8) -> %void {
const buf = %return allocator.alloc(u8, file_path.len + 1);
defer allocator.free(buf);
@ -459,3 +494,37 @@ pub fn copyFile(allocator: &Allocator, source_path: []const u8, dest_path: []con
return;
}
}
pub fn rename(allocator: &Allocator, old_path: []const u8, new_path: []const u8) -> %void {
const full_buf = %return allocator.alloc(u8, old_path.len + new_path.len + 2);
defer allocator.free(full_buf);
const old_buf = full_buf;
mem.copy(u8, old_buf, old_path);
old_buf[old_path.len] = 0;
const new_buf = full_buf[old_path.len + 1...];
mem.copy(u8, new_buf, new_path);
new_buf[new_path.len] = 0;
const err = posix.getErrno(posix.rename(old_buf.ptr, new_buf.ptr));
if (err > 0) {
return switch (err) {
errno.EACCES, errno.EPERM => error.AccessDenied,
errno.EBUSY => error.FileBusy,
errno.EDQUOT => error.DiskQuota,
errno.EFAULT, errno.EINVAL => unreachable,
errno.EISDIR => error.IsDir,
errno.ELOOP => error.SymLinkLoop,
errno.EMLINK => error.LinkQuotaExceeded,
errno.ENAMETOOLONG => error.NameTooLong,
errno.ENOENT, errno.ENOTDIR => error.FileNotFound,
errno.ENOMEM => error.SystemResources,
errno.ENOSPC => error.NoSpaceLeft,
errno.EEXIST, errno.ENOTEMPTY => error.PathAlreadyExists,
errno.EROFS => error.ReadOnlyFileSystem,
errno.EXDEV => error.RenameAcrossMountPoints,
else => error.Unexpected,
};
}
}

4
std/os/linux.zig
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@ -311,6 +311,10 @@ pub fn pwrite(fd: i32, buf: &const u8, count: usize, offset: usize) -> usize {
arch.syscall4(arch.SYS_pwrite, usize(fd), usize(buf), count, offset)
}
pub fn rename(old: &const u8, new: &const u8) -> usize {
arch.syscall2(arch.SYS_rename, usize(old), usize(new))
}
pub fn open(path: &const u8, flags: usize, perm: usize) -> usize {
arch.syscall3(arch.SYS_open, usize(path), flags, perm)
}