1. 可以持续调用 head() 以低成本获取最新的 "head" Commit
2. 可以永久保留那些 Commit 对象（尽管这可能以内存使用为代价）
3. 当 Writer 调用 push() 时，最终会赶上

示例

此示例显示了 Writer 的典型用法

1. 添加一些更改
2. 读取它们本地更改
3. 通过调用 commit() 锁定那些更改
4. 最后通过调用 push() 将那些更改揭示给读者

和 Reader

1. 持续读取它们最新的当前数据 "head" Commit
2. 当 Writer 通过调用 push() 发布时，最终会赶上

代码

use someday::{
	Patch,
	Writer,Reader,
	Commit,CommitRef,
	CommitInfo,PushInfo,
};

// Create Reader/Writer for the string "hello".
let (r, mut w) = someday::new("hello".to_string());

// The readers see the data.
let commit: CommitRef<String> = r.head();
assert_eq!(commit.data, "hello");
assert_eq!(commit.timestamp, 0);

// Writer writes some data, but does not commit.
w.add(Patch::Ptr(|w, _| w.push_str(" world")));
// Nothing committed, data still the same everywhere.
let data: &String = w.data();
assert_eq!(*data, "hello");
// Patches not yet committed:
assert_eq!(w.staged().len(), 1);

// Readers still see old data.
assert_eq!(r.head().data, "hello");

// Writer writes some more data.
w.add(Patch::Ptr(|w, _| w.push_str("!")));
// Readers still see old data.
assert_eq!(r.head().data, "hello");

// Writer commits their patches.
let commit_info: CommitInfo = w.commit();
// The 2 operation were committed locally
// (only the Writer sees them).
assert_eq!(commit_info.patches, 2);

// Readers still see old data.
assert_eq!(r.head().data, "hello");

// Writer finally reveals those
// changes by calling `push()`.
let push_info: PushInfo = w.push();
assert_eq!(push_info.commits, 1);

// Now readers see updates.
let commit: CommitRef<String> = r.head();
assert_eq!(commit.data, "hello world!");
// Each call to `.commit()` added 1 to the timestamp.
assert_eq!(commit.timestamp, 1);

功能标志

这些功能用于（反）序列化。

您可以直接从

• Writer<将您的数据 T 序列化或反序列化>
• Reader<将您的数据 T 序列化或反序列化>
• Commit<将您的数据 T 序列化或反序列化>

MSRV

支持的最低Rust版本是 1.70.0。