migrate to Zig Build v2

Author: motiejus

lib/std/Build/Cache.zig

@@ -31,6 +31,16 @@ pub const Directory = struct {
         }
     }
 
+    pub fn tmpFilePath(self: *const Directory, ally: Allocator, suffix: []const u8) error{OutOfMemory}![]const u8 {
+        const s = std.fs.path.sep_str;
+        const rand_int = std.crypto.random.int(u64);
+        if (self.path) |p| {
+            return std.fmt.allocPrint(ally, "{s}" ++ s ++ "tmp" ++ s ++ "{x}-{s}", .{ p, rand_int, suffix });
+        } else {
+            return std.fmt.allocPrint(ally, "tmp" ++ s ++ "{x}-{s}", .{ rand_int, suffix });
+        }
+    }
+
     /// Whether or not the handle should be closed, or the path should be freed
     /// is determined by usage, however this function is provided for convenience
     /// if it happens to be what the caller needs.

src/main.zig

@@ -3147,50 +3147,18 @@ fn buildOutputType(
         temp_files_for_comp.deinit();
     }
 
-    // if a c_source_file is not a regular file, dump it to a tempdir
-    // and replace the src_name with the newly created file.
-    // translate-c works fine with streams; other actions don't.
+    // if a c_source_file is "-", dump it to a tempdir and replace the src_name
+    // with the newly created file. translate-c works fine with streams; other
+    // actions don't.
     if (arg_mode != .translate_c) {
-        c_src_loop: for (c_source_files.items) |*src| {
-            // optimization: if the file extension is known, assume it is
-            // a regular file and keep going. This is in the hot path.
-            // If we remove this check, all input files will get an extra
-            // syscall or two of overhead.
-            if (Compilation.classifyFileExt(src.src_path) != .unknown)
-                continue;
+        for (c_source_files.items) |*src| {
+            if (!mem.eql(u8, src.src_path, "-")) continue;
 
-            // if the extension was not supplied or recognized, bail.
             if (src.ext == null)
                 fatal("-E or -x is required when reading from a non-regular file", .{});
 
-            var close_fd = true;
-            const fd = blk: {
-                if (mem.eql(u8, src.src_path, "-")) {
-                    close_fd = false;
-                    break :blk io.getStdIn().handle;
-                }
-
-                // all things in a windows filesystem are files or directories.
-                // Therefore, if it is not stdin, it is a file.
-                if (builtin.os.tag == .windows)
-                    continue :c_src_loop;
-
-                // On POSIX or wasm need to determine if a given path is a
-                // stream. 2 choices:
-                // 1. open + lseek. If lseek fails, it is a stream. Always 2
-                //    syscalls.
-                // 2. fstat + optional open. If fstat says it's a file, return
-                //    use it as such. If it is not a file, open and return the
-                //    file descriptor. 1,5 syscall. Use this.
-                var stat_info = try std.os.fstatat(fs.cwd().fd, src.src_path, 0);
-                if (stat_info.mode & std.os.S.IFMT == std.os.S.IFREG)
-                    continue :c_src_loop;
-
-                break :blk try std.os.open(src.src_path, std.os.O.RDONLY, 0);
-            };
-            defer if (close_fd) std.os.close(fd);
-
-            const new_file = try copyToFile(arena, fd, local_cache_directory);
+            // "-" is stdin. Dump it to a real file.
+            const new_file = try copyToFile(arena, io.getStdIn().handle, local_cache_directory);
             try temp_files_for_comp.append(new_file);
             src.src_path = new_file;
         }