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Split into read and stream lifetimes

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Much easier to read, and compiles all the examples we need.
This commit is contained in:
Bradlee Speice
2019-05-09 13:58:27 -04:00
parent d41f578c83
commit 37ea0f5cc1
3 changed files with 186 additions and 47 deletions
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46
tests/lifetime_validation.rs
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@ -1,52 +1,48 @@
//! Example using hand-coded structs to validate that the borrow checker
//! will allow our code to actually run
use kaitai::{BytesReader, KError, KResult, KStream, KStruct, KStructUnit};
use kaitai::{BytesReader, KError, KResult, KStream, KStruct, KStructUnit, TypedStack};
#[derive(Debug, PartialEq, Clone, Default)]
struct TestRootStruct<'a> {
pub bytes: &'a [u8],
pub child: Option<TestChildStruct<'a>>,
struct TestRootStruct<'s> {
pub bytes: &'s [u8],
pub child: Option<TestChildStruct<'s>>,
}
#[derive(Debug, PartialEq, Clone, Default)]
struct TestChildStruct<'a> {
pub bytes: &'a [u8],
pub root_bytes: &'a [u8],
struct TestChildStruct<'s> {
pub bytes: &'s [u8],
pub root_bytes: &'s [u8],
}
impl<'a> KStruct<'a> for TestRootStruct<'a> {
type Parent = KStructUnit;
type Root = TestRootStruct<'a>;
impl<'r, 's: 'r> KStruct<'r, 's> for TestRootStruct<'s> {
type Root = Self;
type ParentStack = (KStructUnit);
fn read<'s: 'a, S: KStream>(
fn read<S: KStream>(
&mut self,
_io: &'s S,
_root: Option<&Self::Root>,
_parent: Option<&Self::Parent>,
_root: Option<&'r Self::Root>,
_parent: TypedStack<Self::ParentStack>,
) -> KResult<'s, ()> {
self.bytes = _io.read_bytes(1)?;
// TODO: `new` method in KStruct?
let mut child = TestChildStruct::default();
// Implementation note: because callers of `read` can't call us as
// `struct.read(_io, Some(struct), None)`, we have to use the `or`
// call below to give an immutable copy of ourselves to the child
child.read(_io, _root.or(Some(self)), Some(self))?;
child.read(_io, Some(self), _parent.push(self))?;
self.child = Some(child);
Ok(())
}
}
impl<'a> KStruct<'a> for TestChildStruct<'a> {
type Parent = TestRootStruct<'a>;
type Root = TestRootStruct<'a>;
impl<'r, 's: 'r> KStruct<'r, 's> for TestChildStruct<'s> {
type Root = <TestRootStruct<'s> as KStruct<'r, 's>>::Root;
type ParentStack = (&'r TestRootStruct<'s>, <TestRootStruct<'s> as KStruct<'r, 's>>::ParentStack);
fn read<'s: 'a, S: KStream>(
fn read<S: KStream>(
&mut self,
_io: &'s S,
_root: Option<&Self::Root>,
_parent: Option<&Self::Parent>,
_root: Option<&'r Self::Root>,
_parent: TypedStack<Self::ParentStack>,
) -> KResult<'s, ()> {
self.bytes = _io.read_bytes(1).unwrap();
_root.map(|r| self.root_bytes = r.bytes).ok_or(KError::MissingRoot)?;
@ -61,7 +57,7 @@ fn basic_parse() {
let mut reader = BytesReader::new(&bytes);
let mut root = TestRootStruct::default();
let res = root.read(&mut reader, None, None);
let res = root.read(&mut reader, None, KStructUnit::parent_stack());
assert!(res.is_ok());
assert_eq!([1], root.bytes);