Unify and pluralize promise resolution syscalls

packages/SwingSet/src/kernel/cleanup.js

@@ -1,4 +1,4 @@
-import { kdebug } from './kdebug';
+// import { kdebug } from './kdebug';
 import { parseKernelSlot } from './parseKernelSlots';
 
 // XXX temporary flags to control features during development
@@ -65,36 +65,36 @@ export function deleteCListEntryIfEasy(
 export function getKpidsToRetire(kernelKeeper, rootKPID, rootKernelData) {
   const seen = new Set();
   function scanKernelPromise(kpid, kernelData) {
-    kdebug(`### scanning ${kpid} ${JSON.stringify(kernelData)}`);
+    // kdebug(`### scanning ${kpid} ${JSON.stringify(kernelData)}`);
     seen.add(kpid);
     if (kernelData) {
       for (const slot of kernelData.slots) {
         const { type } = parseKernelSlot(slot);
-        kdebug(`## examine ${kpid} slot ${slot}`);
+        // kdebug(`## examine ${kpid} slot ${slot}`);
         if (type === 'promise') {
           if (!seen.has(slot)) {
             const kp = kernelKeeper.getKernelPromise(slot);
             const { data, state } = kp;
-            kdebug(`## state of ${slot} is: ${JSON.stringify(kp)}`);
+            // kdebug(`## state of ${slot} is: ${JSON.stringify(kp)}`);
             if (state !== 'unresolved') {
               if (data) {
                 scanKernelPromise(slot, data);
               }
             } else {
-              kdebug(`## ${slot} is still unresolved`);
+              // kdebug(`## ${slot} is still unresolved`);
             }
           } else {
-            kdebug(`## ${slot} previously seen`);
+            // kdebug(`## ${slot} previously seen`);
           }
         } else {
-          kdebug(`## ${slot} is not a promise`);
+          // kdebug(`## ${slot} is not a promise`);
         }
       }
     } else {
-      kdebug(`## ${kpid} has no data`);
+      // kdebug(`## ${kpid} has no data`);
     }
   }
-  kdebug(`## scanning ${rootKPID}`);
+  // kdebug(`## scanning ${rootKPID}`);
   scanKernelPromise(rootKPID, rootKernelData);
   return Array.from(seen);
 }

packages/SwingSet/src/kernel/kernel.js

@@ -447,19 +447,6 @@ export default function buildKernel(
     }
   }
 
-  function statNameForNotify(state) {
-    switch (state) {
-      case 'fulfilledToPresence':
-        return 'dispatchNotifyFulfillToPresence';
-      case 'fulfilledToData':
-        return 'dispatchNotifyFulfillToData';
-      case 'rejected':
-        return 'dispatchNotifyReject';
-      default:
-        throw Error(`unknown promise state ${state}`);
-    }
-  }
-
   async function processNotify(message) {
     const { vatID, kpid } = message;
     insistVatID(vatID);
@@ -470,7 +457,7 @@ export default function buildKernel(
       kdebug(`dropping notify of ${kpid} to ${vatID} because vat is dead`);
     } else {
       const p = kernelKeeper.getKernelPromise(kpid);
-      kernelKeeper.incStat(statNameForNotify(p.state));
+      kernelKeeper.incStat('dispatchNotify');
       const vatKeeper = kernelKeeper.getVatKeeper(vatID);
 
       assert(p.state !== 'unresolved', details`spurious notification ${kpid}`);

packages/SwingSet/src/kernel/kernelSyscall.js

@@ -100,58 +100,59 @@ export function makeKernelSyscallHandler(tools) {
     return OKNULL;
   }
 
-  function fulfillToPresence(vatID, kpid, targetSlot) {
-    insistVatID(vatID);
-    insistKernelType('promise', kpid);
-    insistKernelType('object', targetSlot);
-    kernelKeeper.incStat('syscalls');
-    kernelKeeper.incStat('syscallFulfillToPresence');
-    const p = kernelKeeper.getResolveablePromise(kpid, vatID);
-    const { subscribers, queue } = p;
-    kernelKeeper.fulfillKernelPromiseToPresence(kpid, targetSlot);
-    notifySubscribersAndQueue(kpid, vatID, subscribers, queue);
-    // todo: some day it'd be nice to delete the promise table entry now. To
-    // do that correctly, we must make sure no vats still hold pointers to
-    // it, which means vats must drop their refs when they get notified about
-    // the resolution ("you knew it was resolved, you shouldn't be sending
-    // any more messages to it, send them to the resolution instead"), and we
-    // must wait for those notifications to be delivered.
-    if (p.policy === 'logAlways') {
-      console.log(`${kpid}.policy logAlways: fulfillToPresence ${targetSlot}`);
+  function extractPresenceIfPresent(data) {
+    const body = JSON.parse(data.body);
+    if (
+      body &&
+      typeof body === 'object' &&
+      body['@qclass'] === 'slot' &&
+      body.index === 0
+    ) {
+      if (data.slots.length === 1) {
+        const slot = data.slots[0];
+        const { type } = parseKernelSlot(slot);
+        if (type === 'object') {
+          return slot;
+        }
+      }
     }
-    return OKNULL;
+    return null;
   }
 
-  function fulfillToData(vatID, kpid, data) {
+  function resolve(vatID, resolutions) {
     insistVatID(vatID);
-    insistKernelType('promise', kpid);
-    insistCapData(data);
     kernelKeeper.incStat('syscalls');
-    kernelKeeper.incStat('syscallFulfillToData');
-    const p = kernelKeeper.getResolveablePromise(kpid, vatID);
-    const { subscribers, queue } = p;
-    let idx = 0;
-    for (const dataSlot of data.slots) {
-      kernelKeeper.incrementRefCount(dataSlot, `fulfill|s${idx}`);
-      idx += 1;
+    kernelKeeper.incStat('syscallResolve');
+    for (const resolution of resolutions) {
+      const [kpid, rejected, data] = resolution;
+      insistKernelType('promise', kpid);
+      insistCapData(data);
+      if (rejected) {
+        resolveToError(kpid, data, vatID);
+      } else {
+        const p = kernelKeeper.getResolveablePromise(kpid, vatID);
+        const { subscribers, queue } = p;
+        let idx = 0;
+        for (const dataSlot of data.slots) {
+          kernelKeeper.incrementRefCount(dataSlot, `resolve|s${idx}`);
+          idx += 1;
+        }
+        const presence = extractPresenceIfPresent(data);
+        if (presence) {
+          kernelKeeper.fulfillKernelPromiseToPresence(kpid, presence);
+        } else if (rejected) {
+          kernelKeeper.rejectKernelPromise(kpid, data);
+        } else {
+          kernelKeeper.fulfillKernelPromiseToData(kpid, data);
+        }
+        notifySubscribersAndQueue(kpid, vatID, subscribers, queue);
+        if (p.policy === 'logAlways') {
+          console.log(
+            `${kpid}.policy logAlways: resolve ${JSON.stringify(data)}`,
+          );
+        }
+      }
     }
-    kernelKeeper.fulfillKernelPromiseToData(kpid, data);
-    notifySubscribersAndQueue(kpid, vatID, subscribers, queue);
-    if (p.policy === 'logAlways') {
-      console.log(
-        `${kpid}.policy logAlways: fulfillToData ${JSON.stringify(data)}`,
-      );
-    }
-    return OKNULL;
-  }
-
-  function reject(vatID, kpid, data) {
-    insistVatID(vatID);
-    insistKernelType('promise', kpid);
-    insistCapData(data);
-    kernelKeeper.incStat('syscalls');
-    kernelKeeper.incStat('syscallReject');
-    resolveToError(kpid, data, vatID);
     return OKNULL;
   }
 
@@ -164,12 +165,8 @@ export function makeKernelSyscallHandler(tools) {
         return invoke(...args);
       case 'subscribe':
         return subscribe(...args);
-      case 'fulfillToPresence':
-        return fulfillToPresence(...args);
-      case 'fulfillToData':
-        return fulfillToData(...args);
-      case 'reject':
-        return reject(...args);
+      case 'resolve':
+        return resolve(...args);
       case 'exit':
         return exit(...args);
       case 'vatstoreGet':
@@ -187,9 +184,7 @@ export function makeKernelSyscallHandler(tools) {
     send, // TODO remove these individual ones
     invoke,
     subscribe,
-    fulfillToPresence,
-    fulfillToData,
-    reject,
+    resolve,
     doKernelSyscall,
   });
   return kernelSyscallHandler;

packages/SwingSet/src/kernel/liveSlots.js

@@ -1,7 +1,6 @@
 /* global HandledPromise */
 
 import {
-  QCLASS,
   Remotable,
   Far,
   getInterfaceOf,
@@ -476,32 +475,8 @@ function build(syscall, forVatID, cacheSize, vatPowers, vatParameters) {
     return res => {
       harden(res);
       lsdebug(`ls.thenResolve fired`, res);
-
-      // We need to know if this is resolving to an imported/exported
-      // presence, because then the kernel can deliver queued messages. We
-      // could build a simpler way of doing this.
       const ser = m.serialize(res);
-      lsdebug(` ser ${ser.body} ${JSON.stringify(ser.slots)}`);
-      // find out what resolution category we're using
-      const unser = JSON.parse(ser.body);
-      if (
-        Object(unser) === unser &&
-        QCLASS in unser &&
-        unser[QCLASS] === 'slot'
-      ) {
-        const slot = ser.slots[unser.index];
-        insistVatType('object', slot);
-        syscall.fulfillToPresence(promiseID, slot);
-      } else {
-        // if it resolves to data, .thens fire but kernel-queued messages are
-        // rejected, because you can't send messages to data
-        syscall.fulfillToData(promiseID, ser);
-      }
-
-      // If we were *also* waiting on this promise (perhaps we received it as
-      // an argument, and also as a result=), then we are responsible for
-      // notifying ourselves. The kernel assumes we're a grownup and don't
-      // need to be reminded of something we did ourselves.
+      syscall.resolve([[promiseID, false, ser]]);
       const pRec = importedPromisesByPromiseID.get(promiseID);
       if (pRec) {
         pRec.resolve(res);
@@ -515,7 +490,7 @@ function build(syscall, forVatID, cacheSize, vatPowers, vatParameters) {
       harden(rej);
       lsdebug(`ls thenReject fired`, rej);
       const ser = m.serialize(rej);
-      syscall.reject(promiseID, ser);
+      syscall.resolve([[promiseID, true, ser]]);
       const pRec = importedPromisesByPromiseID.get(promiseID);
       if (pRec) {
         pRec.reject(rej);

packages/SwingSet/src/kernel/state/kernelKeeper.js

@@ -155,16 +155,11 @@ export default function makeKernelKeeper(storage, kernelSlog) {
     syscalls: 0,
     syscallSend: 0,
     syscallSubscribe: 0,
-    syscallFulfillToData: 0,
-    syscallFulfillToPresence: 0,
-    syscallReject: 0,
+    syscallResolve: 0,
     syscallCallNow: 0,
     dispatches: 0,
     dispatchDeliver: 0,
     dispatchNotify: 0,
-    dispatchNotifyFulfillToData: 0,
-    dispatchNotifyFulfillToPresence: 0,
-    dispatchNotifyReject: 0,
     clistEntries: 0,
     clistEntriesUp: 0,
     clistEntriesDown: 0,

packages/SwingSet/src/kernel/vatManager/nodeWorkerSupervisor.js

@@ -86,9 +86,7 @@ parentPort.on('message', ([type, ...margs]) => {
         throw Error(`nodeWorker cannot syscall.callNow`);
       },
       subscribe: (...args) => doSyscall(['subscribe', ...args]),
-      fulfillToData: (...args) => doSyscall(['fulfillToData', ...args]),
-      fulfillToPresence: (...args) => doSyscall(['fulfillToPresence', ...args]),
-      reject: (...args) => doSyscall(['reject', ...args]),
+      resolve: (...args) => doSyscall(['resolve', ...args]),
     });
 
     const vatID = 'demo-vatID';

packages/SwingSet/src/kernel/vatManager/subprocessSupervisor.js

@@ -106,9 +106,7 @@ fromParent.on('data', ([type, ...margs]) => {
         throw Error(`nodeWorker cannot syscall.callNow`);
       },
       subscribe: (...args) => doSyscall(['subscribe', ...args]),
-      fulfillToData: (...args) => doSyscall(['fulfillToData', ...args]),
-      fulfillToPresence: (...args) => doSyscall(['fulfillToPresence', ...args]),
-      reject: (...args) => doSyscall(['reject', ...args]),
+      resolve: (...args) => doSyscall(['resolve', ...args]),
     });
 
     const vatID = 'demo-vatID';

packages/SwingSet/src/kernel/vatManager/syscall.js

@@ -98,9 +98,7 @@ export function createSyscall(transcriptManager) {
     send: (...args) => doSyscall(['send', ...args]),
     callNow: (...args) => doSyscall(['callNow', ...args]),
     subscribe: (...args) => doSyscall(['subscribe', ...args]),
-    fulfillToData: (...args) => doSyscall(['fulfillToData', ...args]),
-    fulfillToPresence: (...args) => doSyscall(['fulfillToPresence', ...args]),
-    reject: (...args) => doSyscall(['reject', ...args]),
+    resolve: (...args) => doSyscall(['resolve', ...args]),
     exit: (...args) => doSyscall(['exit', ...args]),
     vatstoreGet: (...args) => doSyscall(['vatstoreGet', ...args]),
     vatstoreSet: (...args) => doSyscall(['vatstoreSet', ...args]),