Module mem 

Stable memory allocator and related structs Various functions and data structures to organize and work with raw stable memory.

This crate provides a notion of “stable memory ownership”. This is a set of techniques, that make data stored in stable memory appear like it gets automatically garbage collected by Rust’s borrower. Each stable memory primitive includes a stable drop flag - a special flag, that is used by Rust to understand, whether it should release stable memory, when it naturally drops the value, or not.

Stable drop flag rules are simple:

1. When you write something to stable memory, set its drop flag to off position.
2. When you read something from stable memory, and you don’t have an intention to move it, set the drop flag to off position.
3. When you read something from stable memory with an intention to move this data somewhere else, set the drop flag to on position.
4. When you Drop the value, if the drop flag is on - call StableType::stable_drop, otherwise just Drop.

These rules are transparently managed at runtime. For users of this crate it appears like stable memory can “own” some value. A set of lifetimes applied later, on the data structure layer, to make it seem like the value is owned by a particular stable data structure.

If you’re thinking of implementing your own data structure using this crate, check this document for more info on this topic.

Modules

allocator

Stable memory allocator used by every data collection in this crate.

free_block

A struct that is used by StableMemoryAllocator to represent a free block.

s_slice

A primitive smart-pointer that points to an allocated memory block.

Functions

clear^⚠

Wipes out stable memory, making it zero pages again.

read_bytes^⚠

Reads raw bytes from stable memory.

read_fixed_for_move^⚠

Reads a StableType value that will move implementing AsFixedSizeBytes trait from stable memory.

read_fixed_for_reference^⚠

Reads a StableType value that won’t move implementing AsFixedSizeBytes trait from stable memory.

write_bytes^⚠

Write raw bytes to stable memory.

write_fixed^⚠

Writes a StableType value implementing AsFixedSizeBytes trait to stable memory.

Type Aliases

StablePtr

A pointer to something is stable memory.