more sentinel-terminated pointers std lib integration

See #3767

Author: andrewrk

doc/langref.html.in

@@ -4865,7 +4865,7 @@ const mem = std.mem;
 test "cast *[1][*]const u8 to [*]const ?[*]const u8" {
     const window_name = [1][*]const u8{"window name"};
     const x: [*]const ?[*]const u8 = &window_name;
-    assert(mem.eql(u8, std.mem.toSliceConst(u8, x[0].?), "window name"));
+    assert(mem.eql(u8, std.mem.toSliceConst(u8, @ptrCast([*:0]const u8, x[0].?)), "window name"));
 }
       {#code_end#}
       {#header_close#}

lib/std/c.zig

@@ -102,7 +102,7 @@ pub extern "c" fn execve(path: [*]const u8, argv: [*]const ?[*]const u8, envp: [
 pub extern "c" fn dup(fd: fd_t) c_int;
 pub extern "c" fn dup2(old_fd: fd_t, new_fd: fd_t) c_int;
 pub extern "c" fn readlink(noalias path: [*]const u8, noalias buf: [*]u8, bufsize: usize) isize;
-pub extern "c" fn realpath(noalias file_name: [*]const u8, noalias resolved_name: [*]u8) ?[*]u8;
+pub extern "c" fn realpath(noalias file_name: [*]const u8, noalias resolved_name: [*]u8) ?[*:0]u8;
 pub extern "c" fn sigprocmask(how: c_int, noalias set: *const sigset_t, noalias oset: ?*sigset_t) c_int;
 pub extern "c" fn gettimeofday(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
 pub extern "c" fn sigaction(sig: c_int, noalias act: *const Sigaction, noalias oact: ?*Sigaction) c_int;

lib/std/debug.zig

@@ -401,7 +401,7 @@ fn printSourceAtAddressWindows(di: *DebugInfo, out_stream: var, relocated_addres
                 const vaddr_start = coff_section.header.virtual_address + proc_sym.CodeOffset;
                 const vaddr_end = vaddr_start + proc_sym.CodeSize;
                 if (relative_address >= vaddr_start and relative_address < vaddr_end) {
-                    break mem.toSliceConst(u8, @ptrCast([*]u8, proc_sym) + @sizeOf(pdb.ProcSym));
+                    break mem.toSliceConst(u8, @ptrCast([*:0]u8, proc_sym) + @sizeOf(pdb.ProcSym));
                 }
             },
             else => {},
@@ -703,9 +703,9 @@ fn printSourceAtAddressMacOs(di: *DebugInfo, out_stream: var, address: usize, tt
         return;
     };
 
-    const symbol_name = mem.toSliceConst(u8, di.strings.ptr + symbol.nlist.n_strx);
+    const symbol_name = mem.toSliceConst(u8, @ptrCast([*:0]const u8, di.strings.ptr + symbol.nlist.n_strx));
     const compile_unit_name = if (symbol.ofile) |ofile| blk: {
-        const ofile_path = mem.toSliceConst(u8, di.strings.ptr + ofile.n_strx);
+        const ofile_path = mem.toSliceConst(u8, @ptrCast([*:0]const u8, di.strings.ptr + ofile.n_strx));
         break :blk fs.path.basename(ofile_path);
     } else "???";
     if (getLineNumberInfoMacOs(di, symbol.*, adjusted_addr)) |line_info| {
@@ -915,7 +915,7 @@ fn openSelfDebugInfoWindows(allocator: *mem.Allocator) !DebugInfo {
         for (present) |_| {
             const name_offset = try pdb_stream.stream.readIntLittle(u32);
             const name_index = try pdb_stream.stream.readIntLittle(u32);
-            const name = mem.toSlice(u8, name_bytes.ptr + name_offset);
+            const name = mem.toSlice(u8, @ptrCast([*:0]u8, name_bytes.ptr + name_offset));
             if (mem.eql(u8, name, "/names")) {
                 break :str_tab_index name_index;
             }
@@ -1708,7 +1708,7 @@ fn getLineNumberInfoMacOs(di: *DebugInfo, symbol: MachoSymbol, target_address: u
     const gop = try di.ofiles.getOrPut(ofile);
     const mach_o_file = if (gop.found_existing) &gop.kv.value else blk: {
         errdefer _ = di.ofiles.remove(ofile);
-        const ofile_path = mem.toSliceConst(u8, di.strings.ptr + ofile.n_strx);
+        const ofile_path = mem.toSliceConst(u8, @ptrCast([*:0]const u8, di.strings.ptr + ofile.n_strx));
 
         gop.kv.value = MachOFile{
             .bytes = try std.fs.Dir.cwd().readFileAllocAligned(
@@ -1741,7 +1741,7 @@ fn getLineNumberInfoMacOs(di: *DebugInfo, symbol: MachoSymbol, target_address: u
             if (sect.flags & macho.SECTION_TYPE == macho.S_REGULAR and
                 (sect.flags & macho.SECTION_ATTRIBUTES) & macho.S_ATTR_DEBUG == macho.S_ATTR_DEBUG)
             {
-                const sect_name = mem.toSliceConst(u8, &sect.sectname);
+                const sect_name = mem.toSliceConst(u8, @ptrCast([*:0]const u8, &sect.sectname));
                 if (mem.eql(u8, sect_name, "__debug_line")) {
                     gop.kv.value.sect_debug_line = sect;
                 } else if (mem.eql(u8, sect_name, "__debug_info")) {
@@ -2323,8 +2323,8 @@ fn readInitialLengthMem(ptr: *[*]const u8, is_64: *bool) !u64 {
     }
 }
 
-fn readStringMem(ptr: *[*]const u8) []const u8 {
-    const result = mem.toSliceConst(u8, ptr.*);
+fn readStringMem(ptr: *[*]const u8) [:0]const u8 {
+    const result = mem.toSliceConst(u8, @ptrCast([*:0]const u8, ptr.*));
     ptr.* += result.len + 1;
     return result;
 }

lib/std/dynamic_library.zig

@@ -140,7 +140,7 @@ pub const LinuxDynLib = struct {
 };
 
 pub const ElfLib = struct {
-    strings: [*]u8,
+    strings: [*:0]u8,
     syms: [*]elf.Sym,
     hashtab: [*]os.Elf_Symndx,
     versym: ?[*]u16,
@@ -175,7 +175,7 @@ pub const ElfLib = struct {
         const dynv = maybe_dynv orelse return error.MissingDynamicLinkingInformation;
         if (base == maxInt(usize)) return error.BaseNotFound;
 
-        var maybe_strings: ?[*]u8 = null;
+        var maybe_strings: ?[*:0]u8 = null;
         var maybe_syms: ?[*]elf.Sym = null;
         var maybe_hashtab: ?[*]os.Elf_Symndx = null;
         var maybe_versym: ?[*]u16 = null;
@@ -186,7 +186,7 @@ pub const ElfLib = struct {
             while (dynv[i] != 0) : (i += 2) {
                 const p = base + dynv[i + 1];
                 switch (dynv[i]) {
-                    elf.DT_STRTAB => maybe_strings = @intToPtr([*]u8, p),
+                    elf.DT_STRTAB => maybe_strings = @intToPtr([*:0]u8, p),
                     elf.DT_SYMTAB => maybe_syms = @intToPtr([*]elf.Sym, p),
                     elf.DT_HASH => maybe_hashtab = @intToPtr([*]os.Elf_Symndx, p),
                     elf.DT_VERSYM => maybe_versym = @intToPtr([*]u16, p),
@@ -230,7 +230,7 @@ pub const ElfLib = struct {
     }
 };
 
-fn checkver(def_arg: *elf.Verdef, vsym_arg: i32, vername: []const u8, strings: [*]u8) bool {
+fn checkver(def_arg: *elf.Verdef, vsym_arg: i32, vername: []const u8, strings: [*:0]u8) bool {
     var def = def_arg;
     const vsym = @bitCast(u32, vsym_arg) & 0x7fff;
     while (true) {

lib/std/event/fs.zig

@@ -58,8 +58,7 @@ pub const Request = struct {
         };
 
         pub const Open = struct {
-            /// must be null terminated. TODO https://github.com/ziglang/zig/issues/265
-            path: []const u8,
+            path: [:0]const u8,
             flags: u32,
             mode: File.Mode,
             result: Error!fd_t,
@@ -68,8 +67,7 @@ pub const Request = struct {
         };
 
         pub const WriteFile = struct {
-            /// must be null terminated. TODO https://github.com/ziglang/zig/issues/265
-            path: []const u8,
+            path: [:0]const u8,
             contents: []const u8,
             mode: File.Mode,
             result: Error!void,

lib/std/fs.zig

@@ -28,6 +28,7 @@ pub const GetAppDataDirError = @import("fs/get_app_data_dir.zig").GetAppDataDirE
 /// This represents the maximum size of a UTF-8 encoded file path.
 /// All file system operations which return a path are guaranteed to
 /// fit into a UTF-8 encoded array of this length.
+/// The byte count includes room for a null sentinel byte.
 pub const MAX_PATH_BYTES = switch (builtin.os) {
     .linux, .macosx, .ios, .freebsd, .netbsd, .dragonfly => os.PATH_MAX,
     // Each UTF-16LE character may be expanded to 3 UTF-8 bytes.
@@ -227,7 +228,7 @@ pub const AtomicFile = struct {
             try crypto.randomBytes(rand_buf[0..]);
             b64_fs_encoder.encode(tmp_path_buf[dirname_component_len..tmp_path_len], rand_buf);
 
-            const file = File.openWriteNoClobberC(&tmp_path_buf, mode) catch |err| switch (err) {
+            const file = File.openWriteNoClobberC(@ptrCast([*:0]u8, &tmp_path_buf), mode) catch |err| switch (err) {
                 error.PathAlreadyExists => continue,
                 // TODO zig should figure out that this error set does not include PathAlreadyExists since
                 // it is handled in the above switch
@@ -247,7 +248,7 @@ pub const AtomicFile = struct {
     pub fn deinit(self: *AtomicFile) void {
         if (!self.finished) {
             self.file.close();
-            deleteFileC(&self.tmp_path_buf) catch {};
+            deleteFileC(@ptrCast([*:0]u8, &self.tmp_path_buf)) catch {};
             self.finished = true;
         }
     }
@@ -258,11 +259,11 @@ pub const AtomicFile = struct {
         self.finished = true;
         if (builtin.os == .windows) {
             const dest_path_w = try os.windows.sliceToPrefixedFileW(self.dest_path);
-            const tmp_path_w = try os.windows.cStrToPrefixedFileW(&self.tmp_path_buf);
+            const tmp_path_w = try os.windows.cStrToPrefixedFileW(@ptrCast([*:0]u8, &self.tmp_path_buf));
             return os.renameW(&tmp_path_w, &dest_path_w);
         }
         const dest_path_c = try os.toPosixPath(self.dest_path);
-        return os.renameC(&self.tmp_path_buf, &dest_path_c);
+        return os.renameC(@ptrCast([*:0]u8, &self.tmp_path_buf), &dest_path_c);
     }
 };
 
@@ -274,12 +275,12 @@ pub fn makeDir(dir_path: []const u8) !void {
 }
 
 /// Same as `makeDir` except the parameter is a null-terminated UTF8-encoded string.
-pub fn makeDirC(dir_path: [*]const u8) !void {
+pub fn makeDirC(dir_path: [*:0]const u8) !void {
     return os.mkdirC(dir_path, default_new_dir_mode);
 }
 
 /// Same as `makeDir` except the parameter is a null-terminated UTF16LE-encoded string.
-pub fn makeDirW(dir_path: [*]const u16) !void {
+pub fn makeDirW(dir_path: [*:0]const u16) !void {
     return os.mkdirW(dir_path, default_new_dir_mode);
 }
 
@@ -327,12 +328,12 @@ pub fn deleteDir(dir_path: []const u8) !void {
 }
 
 /// Same as `deleteDir` except the parameter is a null-terminated UTF8-encoded string.
-pub fn deleteDirC(dir_path: [*]const u8) !void {
+pub fn deleteDirC(dir_path: [*:0]const u8) !void {
     return os.rmdirC(dir_path);
 }
 
 /// Same as `deleteDir` except the parameter is a null-terminated UTF16LE-encoded string.
-pub fn deleteDirW(dir_path: [*]const u16) !void {
+pub fn deleteDirW(dir_path: [*:0]const u16) !void {
     return os.rmdirW(dir_path);
 }
 
@@ -688,7 +689,7 @@ pub const Dir = struct {
     }
 
     /// Same as `open` except the parameter is null-terminated.
-    pub fn openC(dir_path_c: [*]const u8) OpenError!Dir {
+    pub fn openC(dir_path_c: [*:0]const u8) OpenError!Dir {
         return cwd().openDirC(dir_path_c);
     }
 
@@ -708,7 +709,7 @@ pub const Dir = struct {
     }
 
     /// Call `File.close` on the result when done.
-    pub fn openReadC(self: Dir, sub_path: [*]const u8) File.OpenError!File {
+    pub fn openReadC(self: Dir, sub_path: [*:0]const u8) File.OpenError!File {
         if (builtin.os == .windows) {
             const path_w = try os.windows.cStrToPrefixedFileW(sub_path);
             return self.openReadW(&path_w);
@@ -719,7 +720,7 @@ pub const Dir = struct {
         return File.openHandle(fd);
     }
 
-    pub fn openReadW(self: Dir, sub_path_w: [*]const u16) File.OpenError!File {
+    pub fn openReadW(self: Dir, sub_path_w: [*:0]const u16) File.OpenError!File {
         const w = os.windows;
 
         var result = File{ .handle = undefined };
@@ -786,7 +787,7 @@ pub const Dir = struct {
     }
 
     /// Same as `openDir` except the parameter is null-terminated.
-    pub fn openDirC(self: Dir, sub_path_c: [*]const u8) OpenError!Dir {
+    pub fn openDirC(self: Dir, sub_path_c: [*:0]const u8) OpenError!Dir {
         if (builtin.os == .windows) {
             const sub_path_w = try os.windows.cStrToPrefixedFileW(sub_path_c);
             return self.openDirW(&sub_path_w);
@@ -805,7 +806,7 @@ pub const Dir = struct {
 
     /// Same as `openDir` except the path parameter is UTF16LE, NT-prefixed.
     /// This function is Windows-only.
-    pub fn openDirW(self: Dir, sub_path_w: [*]const u16) OpenError!Dir {
+    pub fn openDirW(self: Dir, sub_path_w: [*:0]const u16) OpenError!Dir {
         const w = os.windows;
 
         var result = Dir{
@@ -868,7 +869,7 @@ pub const Dir = struct {
     }
 
     /// Same as `deleteFile` except the parameter is null-terminated.
-    pub fn deleteFileC(self: Dir, sub_path_c: [*]const u8) DeleteFileError!void {
+    pub fn deleteFileC(self: Dir, sub_path_c: [*:0]const u8) DeleteFileError!void {
         os.unlinkatC(self.fd, sub_path_c, 0) catch |err| switch (err) {
             error.DirNotEmpty => unreachable, // not passing AT_REMOVEDIR
             else => |e| return e,
@@ -903,7 +904,7 @@ pub const Dir = struct {
     }
 
     /// Same as `deleteDir` except the parameter is null-terminated.
-    pub fn deleteDirC(self: Dir, sub_path_c: [*]const u8) DeleteDirError!void {
+    pub fn deleteDirC(self: Dir, sub_path_c: [*:0]const u8) DeleteDirError!void {
         os.unlinkatC(self.fd, sub_path_c, os.AT_REMOVEDIR) catch |err| switch (err) {
             error.IsDir => unreachable, // not possible since we pass AT_REMOVEDIR
             else => |e| return e,
@@ -912,7 +913,7 @@ pub const Dir = struct {
 
     /// Same as `deleteDir` except the parameter is UTF16LE, NT prefixed.
     /// This function is Windows-only.
-    pub fn deleteDirW(self: Dir, sub_path_w: [*]const u16) DeleteDirError!void {
+    pub fn deleteDirW(self: Dir, sub_path_w: [*:0]const u16) DeleteDirError!void {
         os.unlinkatW(self.fd, sub_path_w, os.AT_REMOVEDIR) catch |err| switch (err) {
             error.IsDir => unreachable, // not possible since we pass AT_REMOVEDIR
             else => |e| return e,
@@ -927,7 +928,7 @@ pub const Dir = struct {
     }
 
     /// Same as `readLink`, except the `pathname` parameter is null-terminated.
-    pub fn readLinkC(self: Dir, sub_path_c: [*]const u8, buffer: *[MAX_PATH_BYTES]u8) ![]u8 {
+    pub fn readLinkC(self: Dir, sub_path_c: [*:0]const u8, buffer: *[MAX_PATH_BYTES]u8) ![]u8 {
         return os.readlinkatC(self.fd, sub_path_c, buffer);
     }
 
@@ -1250,7 +1251,8 @@ pub fn openSelfExe() OpenSelfExeError!File {
     var buf: [MAX_PATH_BYTES]u8 = undefined;
     const self_exe_path = try selfExePath(&buf);
     buf[self_exe_path.len] = 0;
-    return File.openReadC(self_exe_path.ptr);
+    // TODO avoid @ptrCast here using slice syntax with https://github.com/ziglang/zig/issues/3731
+    return File.openReadC(@ptrCast([*:0]u8, self_exe_path.ptr));
 }
 
 test "openSelfExe" {
@@ -1277,7 +1279,7 @@ pub fn selfExePath(out_buffer: *[MAX_PATH_BYTES]u8) SelfExePathError![]u8 {
         var u32_len: u32 = out_buffer.len;
         const rc = std.c._NSGetExecutablePath(out_buffer, &u32_len);
         if (rc != 0) return error.NameTooLong;
-        return mem.toSlice(u8, out_buffer);
+        return mem.toSlice(u8, @ptrCast([*:0]u8, out_buffer));
     }
     switch (builtin.os) {
         .linux => return os.readlinkC("/proc/self/exe", out_buffer),
@@ -1306,9 +1308,9 @@ pub fn selfExePath(out_buffer: *[MAX_PATH_BYTES]u8) SelfExePathError![]u8 {
 }
 
 /// The result is UTF16LE-encoded.
-pub fn selfExePathW() []const u16 {
+pub fn selfExePathW() [:0]const u16 {
     const image_path_name = &os.windows.peb().ProcessParameters.ImagePathName;
-    return mem.toSliceConst(u16, image_path_name.Buffer);
+    return mem.toSliceConst(u16, @ptrCast([*:0]const u16, image_path_name.Buffer));
 }
 
 /// `selfExeDirPath` except allocates the result on the heap.

lib/std/fs/file.zig

@@ -31,7 +31,7 @@ pub const File = struct {
     }
 
     /// Deprecated; call `std.fs.Dir.openReadC` directly.
-    pub fn openReadC(path_c: [*]const u8) OpenError!File {
+    pub fn openReadC(path_c: [*:0]const u8) OpenError!File {
         return std.fs.Dir.cwd().openReadC(path_c);
     }
 
@@ -61,7 +61,7 @@ pub const File = struct {
 
     /// Same as `openWriteMode` except `path` is null-terminated.
     /// TODO: deprecate this and move it to `std.fs.Dir`.
-    pub fn openWriteModeC(path: [*]const u8, file_mode: Mode) OpenError!File {
+    pub fn openWriteModeC(path: [*:0]const u8, file_mode: Mode) OpenError!File {
         if (builtin.os == .windows) {
             const path_w = try windows.cStrToPrefixedFileW(path);
             return openWriteModeW(&path_w, file_mode);
@@ -74,7 +74,7 @@ pub const File = struct {
 
     /// Same as `openWriteMode` except `path` is null-terminated and UTF16LE encoded
     /// TODO: deprecate this and move it to `std.fs.Dir`.
-    pub fn openWriteModeW(path_w: [*]const u16, file_mode: Mode) OpenError!File {
+    pub fn openWriteModeW(path_w: [*:0]const u16, file_mode: Mode) OpenError!File {
         const handle = try windows.CreateFileW(
             path_w,
             windows.GENERIC_WRITE,
@@ -101,7 +101,7 @@ pub const File = struct {
     }
 
     /// TODO: deprecate this and move it to `std.fs.Dir`.
-    pub fn openWriteNoClobberC(path: [*]const u8, file_mode: Mode) OpenError!File {
+    pub fn openWriteNoClobberC(path: [*:0]const u8, file_mode: Mode) OpenError!File {
         if (builtin.os == .windows) {
             const path_w = try windows.cStrToPrefixedFileW(path);
             return openWriteNoClobberW(&path_w, file_mode);
@@ -113,7 +113,7 @@ pub const File = struct {
     }
 
     /// TODO: deprecate this and move it to `std.fs.Dir`.
-    pub fn openWriteNoClobberW(path_w: [*]const u16, file_mode: Mode) OpenError!File {
+    pub fn openWriteNoClobberW(path_w: [*:0]const u16, file_mode: Mode) OpenError!File {
         const handle = try windows.CreateFileW(
             path_w,
             windows.GENERIC_WRITE,
@@ -142,13 +142,13 @@ pub const File = struct {
 
     /// Same as `access` except the parameter is null-terminated.
     /// TODO: deprecate this and move it to `std.fs.Dir`.
-    pub fn accessC(path: [*]const u8) !void {
+    pub fn accessC(path: [*:0]const u8) !void {
         return os.accessC(path, os.F_OK);
     }
 
     /// Same as `access` except the parameter is null-terminated UTF16LE-encoded.
     /// TODO: deprecate this and move it to `std.fs.Dir`.
-    pub fn accessW(path: [*]const u16) !void {
+    pub fn accessW(path: [*:0]const u16) !void {
         return os.accessW(path, os.F_OK);
     }