Gaëtan Renaudeau
7 years ago
8 changed files with 111 additions and 55 deletions
@ -0,0 +1,51 @@ |
|||
// @flow
|
|||
import createSemaphore from 'semaphore' |
|||
import type Transport from '@ledgerhq/hw-transport' |
|||
import CommNodeHid from '@ledgerhq/hw-transport-node-hid' |
|||
|
|||
// all open to device must use openDevice so we can prevent race conditions
|
|||
// and guarantee we do one device access at a time. It also will handle the .close()
|
|||
// NOTE optim: in the future we can debounce the close & reuse the same transport instance.
|
|||
|
|||
type WithDevice = (devicePath: string) => <T>(job: (Transport<*>) => Promise<T>) => Promise<T> |
|||
|
|||
const semaphorePerDevice = {} |
|||
|
|||
export const withDevice: WithDevice = devicePath => { |
|||
const { FORK_TYPE } = process.env |
|||
if (FORK_TYPE !== 'devices') { |
|||
console.warn( |
|||
`deviceAccess is only expected to be used in process 'devices'. Any other usage may lead to race conditions. (Got: '${FORK_TYPE}')`, |
|||
) |
|||
} |
|||
const sem = |
|||
semaphorePerDevice[devicePath] || (semaphorePerDevice[devicePath] = createSemaphore(1)) |
|||
return job => |
|||
takeSemaphorePromise(sem, async () => { |
|||
const t = await CommNodeHid.open(devicePath) |
|||
try { |
|||
const res = await job(t) |
|||
// $FlowFixMe
|
|||
return res |
|||
} finally { |
|||
t.close() |
|||
} |
|||
}) |
|||
} |
|||
|
|||
function takeSemaphorePromise<T>(sem, f: () => Promise<T>): Promise<T> { |
|||
return new Promise((resolve, reject) => { |
|||
sem.take(() => { |
|||
f().then( |
|||
r => { |
|||
sem.leave() |
|||
resolve(r) |
|||
}, |
|||
e => { |
|||
sem.leave() |
|||
reject(e) |
|||
}, |
|||
) |
|||
}) |
|||
}) |
|||
} |
|||
Loading…
Reference in new issue