{"blog_title":"\u3058\u3083\u3042\u3001\u304a\u3046\u3061\u3067\u5b66\u3079\u308b ","image_url":null,"width":"100%","description":"\u306f\u3058\u3081\u306b \u5165\u529b\u3092\u305d\u306e\u307e\u307e\u8fd4\u3059\u304b\u3001\u4e00\u90e8\u66f8\u304d\u63db\u3048\u3066\u304b\u3089\u8fd4\u3059\u304b\u3001\u95a2\u6570\u306e\u4e2d\u3067\u5224\u5b9a\u3059\u308b\u5834\u9762\u304c\u3042\u308a\u307e\u3059\u3002\u7d20\u76f4\u306b\u66f8\u304f\u3068\u300c\u5909\u66f4\u3057\u306a\u3044\u5834\u5408\u3082\u7121\u99c4\u306b String::clone() \u3057\u3066\u3057\u307e\u3046\u300d\u3001\u307e\u305f\u306f\u300c&str \u3092\u8fd4\u3057\u305f\u3044\u304c\u3001\u5909\u66f4\u304c\u3042\u3063\u305f\u6642\u306f\u6240\u6709\u30c7\u30fc\u30bf\u3092\u8fd4\u3057\u305f\u3044\u300d\u3068\u3044\u3046\u30b8\u30ec\u30f3\u30de\u306b\u9665\u308a\u307e\u3059\u3002 std::borrow::Cow<'_, T> (Clone-On-Write) \u306f\u3053\u306e\u30b8\u30ec\u30f3\u30de\u3092\u89e3\u304d\u307e\u3059\u3002\u501f\u7528 (Borrowed) \u3068\u6240\u6709 (Owned) \u306e\u3069\u3061\u3089\u304b\u3092\u9078\u3093\u3067\u8fd4\u305b\u308b enum \u3067\u3001\u300c\u5fc5\u8981\u306b\u306a\u308b\u307e\u3067 allocate \u3057\u306a\u3044\u300d\u304c\u578b\u3067\u8868\u73fe\u3067\u304d\u307e\u3059\u3002 doc.rust-lang.org \u307e\u305a\u52d5\u304f\u30b3\u30fc\u30c9 \u300c\u3059\u3067\u306b\u2026","version":"1.0","provider_name":"Hatena Blog","provider_url":"https://hatena.blog","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fsyu-m-5151.hatenablog.com%2Fentry%2F2026%2F05%2F07%2F121334\" title=\"`Cow&lt;&#39;_, T&gt;` \u3067\u300c\u5909\u66f4\u304c\u5fc5\u8981\u306a\u3068\u304d\u3060\u3051 allocate \u3059\u308b\u300d - \u3058\u3083\u3042\u3001\u304a\u3046\u3061\u3067\u5b66\u3079\u308b \" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","author_name":"syu-m-5151","title":"`Cow<'_, T>` \u3067\u300c\u5909\u66f4\u304c\u5fc5\u8981\u306a\u3068\u304d\u3060\u3051 allocate \u3059\u308b\u300d","published":"2026-05-07 12:13:34","categories":["Rust"],"type":"rich","author_url":"https://blog.hatena.ne.jp/syu-m-5151/","url":"https://syu-m-5151.hatenablog.com/entry/2026/05/07/121334","blog_url":"https://syu-m-5151.hatenablog.com/","height":"190"}