Files
pezkuwi-subxt/substrate/frame/contracts/fixtures/chain_extension.wat
T
Alexander Theißen 51c37ecc15 contracts: Allow runtime authors to define a chain extension (#7548)
* Make host functions return TrapReason

This avoids the need to manually store any trap reasons
to the `Runtime` from the host function. This adds the following
benefits:

* It properly composes with the upcoming chain extensions
* Missing to set a trap value is now a compile error

* Add chain extension

The chain extension is a way for the contract author to add new
host functions for contracts to call.

* Add tests for chain extensions

* Fix regression in set_rent.wat fixture

Not all offsets where properly updated when changing the fixtures
for the new salt on instantiate.

* Pre-charge a weight amount based off the specified length

* Improve fn write docs

* Renamed state to phantom

* Fix typo
2021-01-04 11:15:17 +00:00

47 lines
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WebAssembly Text Format

;; Call chain extension by passing through input and output of this contract
(module
(import "seal0" "seal_call_chain_extension"
(func $seal_call_chain_extension (param i32 i32 i32 i32 i32) (result i32))
)
(import "seal0" "seal_input" (func $seal_input (param i32 i32)))
(import "seal0" "seal_return" (func $seal_return (param i32 i32 i32)))
(import "env" "memory" (memory 16 16))
(func $assert (param i32)
(block $ok
(br_if $ok (get_local 0))
(unreachable)
)
)
;; [0, 4) len of input output
(data (i32.const 0) "\02")
;; [4, 12) buffer for input
;; [12, 16) len of output buffer
(data (i32.const 12) "\02")
;; [16, inf) buffer for output
(func (export "deploy"))
(func (export "call")
(call $seal_input (i32.const 4) (i32.const 0))
;; the chain extension passes through the input and returns it as output
(call $seal_call_chain_extension
(i32.load8_u (i32.const 4)) ;; func_id
(i32.const 4) ;; input_ptr
(i32.load (i32.const 0)) ;; input_len
(i32.const 16) ;; output_ptr
(i32.const 12) ;; output_len_ptr
)
;; the chain extension passes through the func_id
(call $assert (i32.eq (i32.load8_u (i32.const 4))))
(call $seal_return (i32.const 0) (i32.const 16) (i32.load (i32.const 12)))
)
)