| author |  Khang Nguyen Duy <40488299+iceghost@users.noreply.github.com> 2023-07-09 22:18:52+07:00 |
| committer |  Andrew Kelley <andrew@ziglang.org> 2024-01-23 01:03:45-08:00 |
| log | 993a83081a975464d1201597cf6f4cb7f6735284 |
| tree | 08c07b7ad6c2d8b8e24d8e1ac2fe4ba1603b31ed |
| parent | aef1da1634ae12d90e9d59fc0184dadaea38830c |
std.fmt: fix unecessary deref on user-defined format function
When formatting a pointer to user type, currently it needs to be
dereferenced first, then call `formatType` on the child type.
Fix the problem by checking for "format" function on not only the type
itself, but also the struct it points to. Add hasMethod to std.meta.2 files changed, 10 insertions(+), 1 deletions(-)
lib/std/fmt.zig+1-1
| ... | @@ -489,7 +489,7 @@ pub fn formatType( | ... | @@ -489,7 +489,7 @@ pub fn formatType( |
| 489 | return formatAddress(value, options, writer); | 489 | return formatAddress(value, options, writer); |
| 490 | } | 490 | } |
| 491 | 491 | ||
| 492 | if (std.meta.hasFn(T, "format")) { | 492 | if (std.meta.hasMethod(T, "format")) { |
| 493 | return try value.format(actual_fmt, options, writer); | 493 | return try value.format(actual_fmt, options, writer); |
| 494 | } | 494 | } |
| 495 | 495 |
lib/std/meta.zig+9
| ... | @@ -1129,6 +1129,15 @@ pub inline fn hasFn(comptime T: type, comptime name: []const u8) bool { | ... | @@ -1129,6 +1129,15 @@ pub inline fn hasFn(comptime T: type, comptime name: []const u8) bool { |
| 1129 | return @typeInfo(@TypeOf(@field(T, name))) == .Fn; | 1129 | return @typeInfo(@TypeOf(@field(T, name))) == .Fn; |
| 1130 | } | 1130 | } |
| 1131 | 1131 | ||
| 1132 | /// Returns true if a type has a `name` method; `false` otherwise. | ||
| 1133 | /// Result is always comptime-known. | ||
| 1134 | pub inline fn hasMethod(comptime T: type, comptime name: []const u8) bool { | ||
| 1135 | return switch (@typeInfo(T)) { | ||
| 1136 | .Pointer => |P| hasFn(P.child, name), | ||
| 1137 | else => hasFn(T, name), | ||
| 1138 | }; | ||
| 1139 | } | ||
| 1140 | |||
| 1132 | /// True if every value of the type `T` has a unique bit pattern representing it. | 1141 | /// True if every value of the type `T` has a unique bit pattern representing it. |
| 1133 | /// In other words, `T` has no unused bits and no padding. | 1142 | /// In other words, `T` has no unused bits and no padding. |
| 1134 | /// Result is always comptime-known. | 1143 | /// Result is always comptime-known. |