🏗️ [Core Feature]: Pausable

[brozorec]

Overview

A contract module enabling an emergency stop mechanism that can be triggered by authorized accounts. This module provides functionality through trait implementation, making available the functions when_not_paused and when_paused which can be applied to contract functions.

State

const PAUSED: Symbol = symbol_short!("PAUSED");

The contract maintains a boolean state initialized to false (unpaused) in instance storage.

Events

paused

• Emitted when pause is triggered by an account
• Contains the caller's address

unpaused

• Emitted when pause is lifted by an account
• Contains the caller's address

Erros

#[contracterror]
#[repr(u32)]
pub enum PausableError {
    EnforcedPaused = 1,  // Operation failed because contract is paused
    ExpectedPause = 2,   // Operation failed because contract is not paused
}

Core Functions

State Query

fn paused(e: Env) -> bool

Returns true if contract is paused, false otherwise.

Guard Functions

fn when_not_paused(e: Env)
fn when_paused(e: Env)

Function modifiers to restrict operations based on pause state.

State Control

fn pause(e: Env, caller: Address)
fn unpause(e: Env, caller: Address)

Internal functions to trigger and lift the stopped state. Requirements:

• Pause: Contract must not be paused
• Unpause: Contract must be paused
• Both require caller authentication

Security Considerations

• All state-changing operations require explicit caller authentication
• State transitions are protected against invalid sequences
• Events are emitted for all state changes
• Clear error conditions for invalid state transitions