我会尽可能清晰地表达。假设我有以下内容:
struct Foo<'a> {
buffer: &'a [u8],
}
impl<'a> Foo<'a> {
fn create_builder() -> FooBuilder {
FooBuilder::new()
}
fn from_slice(slice: &[u8]) -> Foo {
Foo { buffer: slice }
}
}
struct FooBuilder {
in_progress_buffer: Vec<u8>,
}
impl FooBuilder {
fn new() -> FooBuilder {
FooBuilder { in_progress_buffer: Vec::new() }
}
fn push(&mut self, item: u8) {
self.in_progress_buffer.push(item);
}
fn build_foo(self) -> Foo {
Foo { buffer: self.in_progress_buffer }
}
}
fn main() {
// Option1: Gradually construct Foo from FooBuilder
let mut foo_builder = FooBuilder::new();
foo_builder.push(7);
let foo = foo_builder.build_foo();
// Option2: Construct Foo from a slice
let v = vec![7];
let foo2 = Foo::from_slice(&v);
}
这会导致编译错误:
error[E0106]: missing lifetime specifier
--> src/main.rs:28:27
|
28 | fn build_foo(self) -> Foo {
| ^^^ expected lifetime parameter
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
= help: consider giving it a 'static lifetime
这个模式是否可行?我该如何解决编译错误?
由于在 FooBuilder
版本中,FooBuilder
拥有缓冲区,而我不希望强制 Foo
用户在使用 Foo
的整个过程中都要保持 FooBuilder
在作用域内,所以我不确定应该给出什么生命周期说明。
CoW
。 :) - E net4