std: use Buffer.outStream in std/child_process.zig

Author: daurnimator

lib/std/child_process.zig

@@ -776,37 +776,36 @@ fn windowsCreateProcess(app_name: [*:0]u16, cmd_line: [*:0]u16, envp_ptr: ?[*]u1
 
 /// Caller must dealloc.
 /// Guarantees a null byte at result[result.len].
-fn windowsCreateCommandLine(allocator: *mem.Allocator, argv: []const []const u8) ![]u8 {
+fn windowsCreateCommandLine(allocator: *mem.Allocator, argv: []const []const u8) ![:0]u8 {
     var buf = try Buffer.initSize(allocator, 0);
     defer buf.deinit();
-
-    var buf_stream = buf.outStream();
+    const buf_stream = buf.outStream();
 
     for (argv) |arg, arg_i| {
-        if (arg_i != 0) try buf.appendByte(' ');
+        if (arg_i != 0) try buf_stream.writeByte(' ');
         if (mem.indexOfAny(u8, arg, " \t\n\"") == null) {
-            try buf.append(arg);
+            try buf_stream.writeAll(arg);
             continue;
         }
-        try buf.appendByte('"');
+        try buf_stream.writeByte('"');
         var backslash_count: usize = 0;
         for (arg) |byte| {
             switch (byte) {
                 '\\' => backslash_count += 1,
                 '"' => {
                     try buf_stream.writeByteNTimes('\\', backslash_count * 2 + 1);
-                    try buf.appendByte('"');
+                    try buf_stream.writeByte('"');
                     backslash_count = 0;
                 },
                 else => {
                     try buf_stream.writeByteNTimes('\\', backslash_count);
-                    try buf.appendByte(byte);
+                    try buf_stream.writeByte(byte);
                     backslash_count = 0;
                 },
             }
         }
         try buf_stream.writeByteNTimes('\\', backslash_count * 2);
-        try buf.appendByte('"');
+        try buf_stream.writeByte('"');
     }
 
     return buf.toOwnedSlice();