@metamask/ocap-kernel
Version:
OCap kernel core components
99 lines • 3.03 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.makeDummyMeterControl = makeDummyMeterControl;
const errors_1 = require("@endo/errors");
/**
* Liveslots must be given a MeterControl object so it can turn metering on and
* off in metered execution environments. We have no metering, so this produces
* an object that obeys the MeterControl API but doesn't actually do anything.
*
* @returns a dummy MeterControl object.
*/
function makeDummyMeterControl() {
/** Depth of metering disablement */
let meteringDisabled = 0;
/**
* Test if metering is disabled.
*
* @returns true iff metering is currently off.
*/
function isMeteringDisabled() {
return meteringDisabled > 0;
}
/**
* Require metering to be on.
*
* @param message - Error message to throw if metering is off.
*/
function assertIsMetered(message) {
(0, errors_1.assert)(meteringDisabled === 0, message);
}
/**
* Require metering to be off.
*
* @param message - Error message to throw if metering is on.
*/
function assertNotMetered(message) {
(0, errors_1.assert)(meteringDisabled > 0, message);
}
/**
* Execute a thunk with metering off.
*
* @param thunk - The thunk to execute.
* @returns whatever `thunk` returns.
*/
function runWithoutMetering(thunk) {
meteringDisabled += 1;
try {
return thunk();
}
finally {
meteringDisabled -= 1;
}
}
/**
* Execute an aynchronous thunk with metering off.
*
* @param thunk - The thunk to execute.
* @returns a promise for whatever `thunk` returns.
*/
async function runWithoutMeteringAsync(thunk) {
meteringDisabled += 1;
return Promise.resolve()
.then(() => thunk())
.finally(() => {
meteringDisabled -= 1;
});
}
/**
* Return a version of func that runs outside metering. Since we have no
* metering, everything actually runs outside metering, so func itself would
* do, but we need to wrap it anyway to account for the nesting depth of
* metering disablement.
*
* @param func - The function to wrap.
* @returns A version of `func` that runs without being metered.
*/
function unmetered(func) {
/**
* A version of `func` with `runWithoutMetering` wrapped around it.
*
* @param args - The args to `func`.
* @returns whatever `func` returns.
*/
function wrapped(...args) {
return runWithoutMetering(() => func(...args));
}
return harden(wrapped);
}
const meterControl = {
isMeteringDisabled,
assertIsMetered,
assertNotMetered,
runWithoutMetering,
runWithoutMeteringAsync,
unmetered,
};
return harden(meterControl);
}
//# sourceMappingURL=meter-control.cjs.map