Trait gear_pwasm_utils::rules::Rules

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pub trait Rules {
    // Required methods
    fn instruction_cost(&self, instruction: &Instruction) -> Option<u32>;
    fn memory_grow_cost(&self) -> Option<MemoryGrowCost>;
}
Expand description

An interface that describes instruction costs.

Required Methods§

source

fn instruction_cost(&self, instruction: &Instruction) -> Option<u32>

Returns the cost for the passed instruction.

Returning None makes the gas instrumention end with an error. This is meant as a way to have a partial rule set where any instruction that is not specifed is considered as forbidden.

source

fn memory_grow_cost(&self) -> Option<MemoryGrowCost>

Returns the costs for growing the memory using the memory.grow instruction.

Please note that these costs are in addition to the costs specified by instruction_cost for the memory.grow instruction. Specifying None leads to no additional charge. Those are meant as dynamic costs which take the amount of pages that the memory is grown by into consideration. This is not possible using instruction_cost because those costs depend on the stack and must be injected as code into the function calling memory.grow. Therefore returning Some comes with a performance cost.

Implementors§