redis_rocksdb 0.3.9

use crate::rocksdb_impl::heap::heap::{FieldHeap, MinHeapCompare};
use crate::rocksdb_impl::shared::{make_field_key, make_head_key};
use crate::{Heap, LenType, RrError, WrapDb};

/// 字段名使用 min binary head存放
pub struct MinHeap {}

impl<T: WrapDb> Heap<T> for MinHeap {
	fn peek(&self, t: &T, key: &[u8]) -> Result<Option<(Vec<u8>, Vec<u8>)>, RrError> {
		let head_key = make_head_key(key);
		let mut heap = {
			match t.get(&head_key)? {
				None => return Ok(None),
				Some(v) => FieldHeap::new(v),
			}
		};
		let p = &mut heap as *mut _;
		heap.init(MinHeapCompare { heap: p });
		let field = match heap.peek() {
			None => return Ok(None),
			Some(f) => f,
		};
		let field_key = make_field_key(key, &field);
		let v = {
			match t.get(&field_key)? {
				None => vec![],
				Some(v) => v,
			}
		};
		Ok(Some((field, v)))
	}

	fn pop(&self, t: &T, key: &[u8]) -> Result<Option<(Vec<u8>, Vec<u8>)>, RrError> {
		let head_key = make_head_key(key);
		let mut heap = {
			match t.get(&head_key)? {
				None => return Ok(None),
				Some(v) => FieldHeap::new(v),
			}
		};
		let p = &mut heap as *mut _;
		heap.init(MinHeapCompare { heap: p });
		let field = match heap.pop() {
			None => return Ok(None),
			Some(f) => f,
		};
		let field_key = make_field_key(key, &field);
		let v = {
			match t.get(&field_key)? {
				None => vec![],
				Some(v) => v,
			}
		};
		t.put(&head_key, &heap.data)?;
		t.delete(&field_key)?;
		Ok(Some((field, v)))
	}

	fn push(&self, t: &T, key: &[u8], field: &[u8], value: &[u8]) -> Result<(), RrError> {
		let field_key = make_field_key(key, field);
		if !t.exist(&field_key)? {
			let head_key = make_head_key(key);
			let mut heap = {
				match t.get(&head_key)? {
					None => FieldHeap::new(vec![]),
					Some(v) => FieldHeap::new(v),
				}
			};
			let p = &mut heap as *mut _;
			heap.init(MinHeapCompare { heap: p });
			heap.push(field);
			t.put(&head_key, &heap.data)?;
		}
		t.put(&field_key, value)?;
		Ok(())
	}

	fn len(&self, t: &T, key: &[u8]) -> Result<Option<LenType>, RrError> {
		let head_key = make_head_key(key);
		let heap = match t.get(&head_key)? {
			None => return Ok(None),
			Some(v) => FieldHeap::<MinHeapCompare>::new(v),
		};
		Ok(Some(heap.len() as LenType))
	}

	fn remove_key(&self, t: &T, key: &[u8]) -> Result<(), RrError> {
		let head_key = make_head_key(key);
		let mut heap = {
			match t.get(&head_key)? {
				None => return Ok(()),
				Some(v) => FieldHeap::new(v),
			}
		};
		let p = &mut heap as *mut _;
		heap.init(MinHeapCompare { heap: p });
		loop {
			let field = match heap.pop() {
				None => break,
				Some(f) => f,
			};
			let field_key = make_field_key(key, &field);
			t.delete(&field_key)?;
		}
		t.delete(&head_key)?;
		Ok(())
	}
}

#[cfg(test)]
mod test {
	#[test]
	fn test_min_heap_transactiondb() {
		// let heap = MinHeap {};
		// let key = vec![0 as u8, 1, 2];
		// let f = heap.pop(&key);
	}
}