Merge pull request #8998 from hashicorp/dnephin/lib-ttlcache
lib/ttlcache: extract a new package from agent/cache
This commit is contained in:
Daniel Nephin
GitHub
commit
a0e017791f
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@ -15,7 +15,6 @@
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package cache
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import (
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"container/heap"
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"context"
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"fmt"
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"io"
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@ -28,6 +27,7 @@ import (
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"golang.org/x/time/rate"
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"github.com/hashicorp/consul/lib"
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"github.com/hashicorp/consul/lib/ttlcache"
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)
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//go:generate mockery -all -inpkg
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@ -88,7 +88,7 @@ type Cache struct {
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// internal storage format so changing this should be possible safely.
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entriesLock sync.RWMutex
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entries map[string]cacheEntry
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entriesExpiryHeap *expiryHeap
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entriesExpiryHeap *ttlcache.ExpiryHeap
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// stopped is used as an atomic flag to signal that the Cache has been
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// discarded so background fetches and expiry processing should stop.
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@ -166,16 +166,11 @@ func applyDefaultValuesOnOptions(options Options) Options {
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// Further settings can be tweaked on the returned value.
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func New(options Options) *Cache {
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options = applyDefaultValuesOnOptions(options)
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// Initialize the heap. The buffer of 1 is really important because
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// its possible for the expiry loop to trigger the heap to update
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// itself and it'd block forever otherwise.
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h := &expiryHeap{NotifyCh: make(chan struct{}, 1)}
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heap.Init(h)
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ctx, cancel := context.WithCancel(context.Background())
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c := &Cache{
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types: make(map[string]typeEntry),
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entries: make(map[string]cacheEntry),
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entriesExpiryHeap: h,
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entriesExpiryHeap: ttlcache.NewExpiryHeap(),
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stopCh: make(chan struct{}),
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options: options,
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rateLimitContext: ctx,
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@ -406,8 +401,7 @@ RETRY_GET:
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// Touch the expiration and fix the heap.
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c.entriesLock.Lock()
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entry.Expiry.Update(r.TypeEntry.Opts.LastGetTTL)
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c.entriesExpiryHeap.Fix(entry.Expiry)
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c.entriesExpiryHeap.Update(entry.Expiry.Index(), r.TypeEntry.Opts.LastGetTTL)
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c.entriesLock.Unlock()
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// We purposely do not return an error here since the cache only works with
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@ -688,10 +682,8 @@ func (c *Cache) fetch(key string, r getOptions, allowNew bool, attempt uint, ign
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// If this is a new entry (not in the heap yet), then setup the
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// initial expiry information and insert. If we're already in
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// the heap we do nothing since we're reusing the same entry.
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if newEntry.Expiry == nil || newEntry.Expiry.HeapIndex == -1 {
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newEntry.Expiry = &cacheEntryExpiry{Key: key}
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newEntry.Expiry.Update(tEntry.Opts.LastGetTTL)
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heap.Push(c.entriesExpiryHeap, newEntry.Expiry)
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if newEntry.Expiry == nil || newEntry.Expiry.Index() == ttlcache.NotIndexed {
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newEntry.Expiry = c.entriesExpiryHeap.Add(key, tEntry.Opts.LastGetTTL)
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}
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c.entries[key] = newEntry
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@ -748,47 +740,30 @@ func backOffWait(failures uint) time.Duration {
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// runExpiryLoop is a blocking function that watches the expiration
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// heap and invalidates entries that have expired.
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func (c *Cache) runExpiryLoop() {
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var expiryTimer *time.Timer
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for {
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// If we have a previous timer, stop it.
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if expiryTimer != nil {
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expiryTimer.Stop()
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}
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// Get the entry expiring soonest
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var entry *cacheEntryExpiry
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var expiryCh <-chan time.Time
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c.entriesLock.RLock()
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if len(c.entriesExpiryHeap.Entries) > 0 {
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entry = c.entriesExpiryHeap.Entries[0]
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expiryTimer = time.NewTimer(time.Until(entry.Expires))
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expiryCh = expiryTimer.C
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}
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timer := c.entriesExpiryHeap.Next()
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c.entriesLock.RUnlock()
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select {
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case <-c.stopCh:
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timer.Stop()
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return
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case <-c.entriesExpiryHeap.NotifyCh:
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// Entries changed, so the heap may have changed. Restart loop.
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timer.Stop()
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continue
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case <-expiryCh:
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case <-timer.Wait():
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c.entriesLock.Lock()
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// Perform cleanup operations on the entry's state, if applicable.
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state := c.entries[entry.Key].State
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if closer, ok := state.(io.Closer); ok {
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entry := timer.Entry
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if closer, ok := c.entries[entry.Key()].State.(io.Closer); ok {
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closer.Close()
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}
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// Entry expired! Remove it.
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delete(c.entries, entry.Key)
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heap.Remove(c.entriesExpiryHeap, entry.HeapIndex)
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// This is subtle but important: if we race and simultaneously
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// evict and fetch a new value, then we set this to -1 to
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// have it treated as a new value so that the TTL is extended.
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entry.HeapIndex = -1
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delete(c.entries, entry.Key())
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c.entriesExpiryHeap.Remove(entry.Index())
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// Set some metrics
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metrics.IncrCounter([]string{"consul", "cache", "evict_expired"}, 1)
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@ -829,7 +804,6 @@ func (c *Cache) Prepopulate(t string, res FetchResult, dc, token, k string) erro
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Index: res.Index,
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FetchedAt: time.Now(),
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Waiter: make(chan struct{}),
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Expiry: &cacheEntryExpiry{Key: key},
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FetchRateLimiter: rate.NewLimiter(
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c.options.EntryFetchRate,
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c.options.EntryFetchMaxBurst,
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@ -15,6 +15,7 @@ import (
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"github.com/stretchr/testify/require"
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"golang.org/x/time/rate"
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"github.com/hashicorp/consul/lib/ttlcache"
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"github.com/hashicorp/consul/sdk/testutil"
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)
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@ -1000,6 +1001,9 @@ func (t *testPartitionType) RegisterOptions() RegisterOptions {
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// Test that background refreshing reports correct Age in failure and happy
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// states.
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func TestCacheGet_refreshAge(t *testing.T) {
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if testing.Short() {
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t.Skip("too slow for -short run")
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}
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t.Parallel()
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require := require.New(t)
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@ -1402,3 +1406,73 @@ OUT:
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}
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}
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}
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func TestCache_ExpiryLoop_ExitsWhenStopped(t *testing.T) {
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c := &Cache{
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stopCh: make(chan struct{}),
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entries: make(map[string]cacheEntry),
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entriesExpiryHeap: ttlcache.NewExpiryHeap(),
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}
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chStart := make(chan struct{})
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chDone := make(chan struct{})
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go func() {
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close(chStart)
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c.runExpiryLoop()
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close(chDone)
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}()
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<-chStart
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close(c.stopCh)
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select {
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case <-chDone:
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case <-time.After(50 * time.Millisecond):
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t.Fatalf("expected loop to exit when stopped")
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}
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}
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func TestCache_Prepopulate(t *testing.T) {
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typ := &fakeType{index: 5}
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c := New(Options{})
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c.RegisterType("t", typ)
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c.Prepopulate("t", FetchResult{Value: 17, Index: 1}, "dc1", "token", "v1")
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ctx := context.Background()
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req := fakeRequest{
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info: RequestInfo{
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Key: "v1",
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Token: "token",
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Datacenter: "dc1",
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MinIndex: 1,
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},
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}
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result, _, err := c.Get(ctx, "t", req)
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require.NoError(t, err)
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require.Equal(t, 17, result)
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}
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type fakeType struct {
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index uint64
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}
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func (f fakeType) Fetch(_ FetchOptions, _ Request) (FetchResult, error) {
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idx := atomic.LoadUint64(&f.index)
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return FetchResult{Value: int(idx * 2), Index: idx}, nil
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}
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func (f fakeType) RegisterOptions() RegisterOptions {
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return RegisterOptions{Refresh: true}
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}
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var _ Type = (*fakeType)(nil)
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type fakeRequest struct {
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info RequestInfo
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}
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func (f fakeRequest) CacheInfo() RequestInfo {
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return f.info
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}
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var _ Request = (*fakeRequest)(nil)
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@ -1,10 +1,11 @@
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package cache
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import (
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"container/heap"
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"time"
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"golang.org/x/time/rate"
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"github.com/hashicorp/consul/lib/ttlcache"
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)
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// cacheEntry stores a single cache entry.
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@ -31,8 +32,8 @@ type cacheEntry struct {
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// Expiry contains information about the expiration of this
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// entry. This is a pointer as its shared as a value in the
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// expiryHeap as well.
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Expiry *cacheEntryExpiry
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// ExpiryHeap as well.
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Expiry *ttlcache.Entry
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// FetchedAt stores the time the cache entry was retrieved for determining
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// it's age later.
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@ -46,118 +47,3 @@ type cacheEntry struct {
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// FetchRateLimiter limits the rate at which fetch is called for this entry.
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FetchRateLimiter *rate.Limiter
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}
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// cacheEntryExpiry contains the expiration information for a cache
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// entry. Any modifications to this struct should be done only while
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// the Cache entriesLock is held.
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type cacheEntryExpiry struct {
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Key string // Key in the cache map
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Expires time.Time // Time when entry expires (monotonic clock)
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HeapIndex int // Index in the heap
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}
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// Update the expiry to d time from now.
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func (e *cacheEntryExpiry) Update(d time.Duration) {
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e.Expires = time.Now().Add(d)
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}
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// expiryHeap is a heap implementation that stores information about
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// when entries expire. Implements container/heap.Interface.
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//
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// All operations on the heap and read/write of the heap contents require
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// the proper entriesLock to be held on Cache.
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type expiryHeap struct {
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Entries []*cacheEntryExpiry
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// NotifyCh is sent a value whenever the 0 index value of the heap
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// changes. This can be used to detect when the earliest value
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// changes.
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//
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// There is a single edge case where the heap will not automatically
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// send a notification: if heap.Fix is called manually and the index
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// changed is 0 and the change doesn't result in any moves (stays at index
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// 0), then we won't detect the change. To work around this, please
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// always call the expiryHeap.Fix method instead.
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NotifyCh chan struct{}
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}
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// Identical to heap.Fix for this heap instance but will properly handle
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// the edge case where idx == 0 and no heap modification is necessary,
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// and still notify the NotifyCh.
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//
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// This is important for cache expiry since the expiry time may have been
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// extended and if we don't send a message to the NotifyCh then we'll never
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// reset the timer and the entry will be evicted early.
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func (h *expiryHeap) Fix(entry *cacheEntryExpiry) {
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idx := entry.HeapIndex
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heap.Fix(h, idx)
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// This is the edge case we handle: if the prev (idx) and current (HeapIndex)
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// is zero, it means the head-of-line didn't change while the value
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// changed. Notify to reset our expiry worker.
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if idx == 0 && entry.HeapIndex == 0 {
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h.notify()
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}
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}
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func (h *expiryHeap) Len() int { return len(h.Entries) }
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func (h *expiryHeap) Swap(i, j int) {
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h.Entries[i], h.Entries[j] = h.Entries[j], h.Entries[i]
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h.Entries[i].HeapIndex = i
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h.Entries[j].HeapIndex = j
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// If we're moving the 0 index, update the channel since we need
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// to re-update the timer we're waiting on for the soonest expiring
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// value.
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if i == 0 || j == 0 {
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h.notify()
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}
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}
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func (h *expiryHeap) Less(i, j int) bool {
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// The usage of Before here is important (despite being obvious):
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// this function uses the monotonic time that should be available
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// on the time.Time value so the heap is immune to wall clock changes.
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return h.Entries[i].Expires.Before(h.Entries[j].Expires)
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}
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// heap.Interface, this isn't expected to be called directly.
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func (h *expiryHeap) Push(x interface{}) {
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entry := x.(*cacheEntryExpiry)
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// Set initial heap index, if we're going to the end then Swap
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// won't be called so we need to initialize
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entry.HeapIndex = len(h.Entries)
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// For the first entry, we need to trigger a channel send because
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// Swap won't be called; nothing to swap! We can call it right away
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// because all heap operations are within a lock.
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if len(h.Entries) == 0 {
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h.notify()
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}
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h.Entries = append(h.Entries, entry)
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}
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// heap.Interface, this isn't expected to be called directly.
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func (h *expiryHeap) Pop() interface{} {
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old := h.Entries
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n := len(old)
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x := old[n-1]
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h.Entries = old[0 : n-1]
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return x
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}
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func (h *expiryHeap) notify() {
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select {
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case h.NotifyCh <- struct{}{}:
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// Good
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default:
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// If the send would've blocked, we just ignore it. The reason this
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// is safe is because NotifyCh should always be a buffered channel.
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// If this blocks, it means that there is a pending message anyways
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// so the receiver will restart regardless.
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}
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}
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@ -1,91 +0,0 @@
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package cache
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import (
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"container/heap"
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"testing"
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"time"
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"github.com/stretchr/testify/require"
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)
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func TestExpiryHeap_impl(t *testing.T) {
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var _ heap.Interface = new(expiryHeap)
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}
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func TestExpiryHeap(t *testing.T) {
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require := require.New(t)
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now := time.Now()
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ch := make(chan struct{}, 10) // buffered to prevent blocking in tests
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h := &expiryHeap{NotifyCh: ch}
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// Init, shouldn't trigger anything
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heap.Init(h)
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testNoMessage(t, ch)
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// Push an initial value, expect one message
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entry := &cacheEntryExpiry{Key: "foo", HeapIndex: -1, Expires: now.Add(100)}
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heap.Push(h, entry)
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require.Equal(0, entry.HeapIndex)
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testMessage(t, ch)
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testNoMessage(t, ch) // exactly one asserted above
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// Push another that goes earlier than entry
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entry2 := &cacheEntryExpiry{Key: "bar", HeapIndex: -1, Expires: now.Add(50)}
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heap.Push(h, entry2)
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require.Equal(0, entry2.HeapIndex)
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require.Equal(1, entry.HeapIndex)
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testMessage(t, ch)
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testNoMessage(t, ch) // exactly one asserted above
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// Push another that goes at the end
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entry3 := &cacheEntryExpiry{Key: "bar", HeapIndex: -1, Expires: now.Add(1000)}
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heap.Push(h, entry3)
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require.Equal(2, entry3.HeapIndex)
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testNoMessage(t, ch) // no notify cause index 0 stayed the same
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// Remove the first entry (not Pop, since we don't use Pop, but that works too)
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remove := h.Entries[0]
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heap.Remove(h, remove.HeapIndex)
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require.Equal(0, entry.HeapIndex)
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require.Equal(1, entry3.HeapIndex)
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testMessage(t, ch)
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testMessage(t, ch) // we have two because two swaps happen
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testNoMessage(t, ch)
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// Let's change entry 3 to be early, and fix it
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entry3.Expires = now.Add(10)
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h.Fix(entry3)
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require.Equal(1, entry.HeapIndex)
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require.Equal(0, entry3.HeapIndex)
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testMessage(t, ch)
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testNoMessage(t, ch)
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// Let's change entry 3 again, this is an edge case where if the 0th
|
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// element changed, we didn't trigger the channel. Our Fix func should.
|
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entry.Expires = now.Add(20)
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h.Fix(entry3)
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require.Equal(1, entry.HeapIndex) // no move
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require.Equal(0, entry3.HeapIndex)
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testMessage(t, ch)
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testNoMessage(t, ch) // one message
|
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}
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|
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func testNoMessage(t *testing.T, ch <-chan struct{}) {
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t.Helper()
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|
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select {
|
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case <-ch:
|
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t.Fatal("should not have a message")
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default:
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}
|
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}
|
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|
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func testMessage(t *testing.T, ch <-chan struct{}) {
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t.Helper()
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|
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select {
|
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case <-ch:
|
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default:
|
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t.Fatal("should have a message")
|
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}
|
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}
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|
|
@ -0,0 +1,195 @@
|
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/*
|
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Package ttlcache provides an ExpiryHeap that can be used by a cache to track the
|
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expiration time of its entries. When an expiry is reached the Timer will fire
|
||||
and the entry can be removed.
|
||||
*/
|
||||
package ttlcache
|
||||
|
||||
import (
|
||||
"container/heap"
|
||||
"time"
|
||||
)
|
||||
|
||||
// Entry in the ExpiryHeap, tracks the index and expiry time of an item in a
|
||||
// ttl cache.
|
||||
type Entry struct {
|
||||
key string
|
||||
expiry time.Time
|
||||
heapIndex int
|
||||
}
|
||||
|
||||
// NotIndexed indicates that the entry does not exist in the heap. Either because
|
||||
// it is nil, or because it was removed.
|
||||
const NotIndexed = -1
|
||||
|
||||
// Index returns the index of this entry within the heap.
|
||||
func (e *Entry) Index() int {
|
||||
if e == nil {
|
||||
return NotIndexed
|
||||
}
|
||||
return e.heapIndex
|
||||
}
|
||||
|
||||
// Key returns the key for the entry in the heap.
|
||||
func (e *Entry) Key() string {
|
||||
return e.key
|
||||
}
|
||||
|
||||
// ExpiryHeap is a heap that is ordered by the expiry time of entries. It may
|
||||
// be used by a cache or storage to expiry items after a TTL.
|
||||
//
|
||||
// ExpiryHeap expects the caller to synchronize calls to most of its methods. This
|
||||
// is necessary because the cache needs to ensure that updates to both its
|
||||
// storage and the ExpiryHeap are synchronized.
|
||||
type ExpiryHeap struct {
|
||||
entries []*Entry
|
||||
|
||||
// NotifyCh is sent a value whenever the 0 index value of the heap
|
||||
// changes. This can be used to detect when the earliest value
|
||||
// changes.
|
||||
NotifyCh chan struct{}
|
||||
}
|
||||
|
||||
// NewExpiryHeap creates and returns a new ExpiryHeap.
|
||||
func NewExpiryHeap() *ExpiryHeap {
|
||||
h := &ExpiryHeap{NotifyCh: make(chan struct{}, 1)}
|
||||
heap.Init((*entryHeap)(h))
|
||||
return h
|
||||
}
|
||||
|
||||
// Add an entry to the heap.
|
||||
//
|
||||
// Must be synchronized by the caller.
|
||||
func (h *ExpiryHeap) Add(key string, expiry time.Duration) *Entry {
|
||||
entry := &Entry{
|
||||
key: key,
|
||||
expiry: time.Now().Add(expiry),
|
||||
// Set the initial heap index to the last index. If the entry is swapped it
|
||||
// will have the correct index set, and if it remains at the end the last
|
||||
// index will be correct.
|
||||
heapIndex: len(h.entries),
|
||||
}
|
||||
heap.Push((*entryHeap)(h), entry)
|
||||
if entry.heapIndex == 0 {
|
||||
h.notify()
|
||||
}
|
||||
return entry
|
||||
}
|
||||
|
||||
// Update the entry that is currently at idx with the new expiry time. The heap
|
||||
// will be rebalanced after the entry is updated.
|
||||
//
|
||||
// Must be synchronized by the caller.
|
||||
func (h *ExpiryHeap) Update(idx int, expiry time.Duration) {
|
||||
if idx == NotIndexed {
|
||||
// the previous entry did not have a valid index, its not in the heap
|
||||
return
|
||||
}
|
||||
entry := h.entries[idx]
|
||||
entry.expiry = time.Now().Add(expiry)
|
||||
heap.Fix((*entryHeap)(h), idx)
|
||||
|
||||
// If the previous index and current index are both zero then Fix did not
|
||||
// swap the entry, and notify must be called here.
|
||||
if idx == 0 || entry.heapIndex == 0 {
|
||||
h.notify()
|
||||
}
|
||||
}
|
||||
|
||||
// Remove the entry at idx from the heap.
|
||||
//
|
||||
// Must be synchronized by the caller.
|
||||
func (h *ExpiryHeap) Remove(idx int) {
|
||||
entry := h.entries[idx]
|
||||
heap.Remove((*entryHeap)(h), idx)
|
||||
|
||||
// A goroutine which is fetching a new value will have a reference to this
|
||||
// entry. When it re-acquires the lock it needs to be informed that
|
||||
// the entry was expired while it was fetching. Setting heapIndex to -1
|
||||
// indicates that the entry is no longer in the heap, and must be re-added.
|
||||
entry.heapIndex = NotIndexed
|
||||
|
||||
if idx == 0 {
|
||||
h.notify()
|
||||
}
|
||||
}
|
||||
|
||||
type entryHeap ExpiryHeap
|
||||
|
||||
func (h *entryHeap) Len() int { return len(h.entries) }
|
||||
|
||||
func (h *entryHeap) Swap(i, j int) {
|
||||
h.entries[i], h.entries[j] = h.entries[j], h.entries[i]
|
||||
h.entries[i].heapIndex = i
|
||||
h.entries[j].heapIndex = j
|
||||
}
|
||||
|
||||
func (h *entryHeap) Less(i, j int) bool {
|
||||
// The usage of Before here is important (despite being obvious):
|
||||
// this function uses the monotonic time that should be available
|
||||
// on the time.Time value so the heap is immune to wall clock changes.
|
||||
return h.entries[i].expiry.Before(h.entries[j].expiry)
|
||||
}
|
||||
|
||||
// heap.Interface, this isn't expected to be called directly.
|
||||
func (h *entryHeap) Push(x interface{}) {
|
||||
h.entries = append(h.entries, x.(*Entry))
|
||||
}
|
||||
|
||||
// heap.Interface, this isn't expected to be called directly.
|
||||
func (h *entryHeap) Pop() interface{} {
|
||||
n := len(h.entries)
|
||||
entries := h.entries
|
||||
last := entries[n-1]
|
||||
h.entries = entries[0 : n-1]
|
||||
return last
|
||||
}
|
||||
|
||||
// notify the timer that the head value has changed, so the expiry time has
|
||||
// also likely changed.
|
||||
func (h *ExpiryHeap) notify() {
|
||||
// Send to channel without blocking. Skips sending if there is already
|
||||
// an item in the buffered channel.
|
||||
select {
|
||||
case h.NotifyCh <- struct{}{}:
|
||||
default:
|
||||
}
|
||||
}
|
||||
|
||||
// Next returns a Timer that waits until the first entry in the heap expires.
|
||||
//
|
||||
// Must be synchronized by the caller.
|
||||
func (h *ExpiryHeap) Next() Timer {
|
||||
if len(h.entries) == 0 {
|
||||
return Timer{}
|
||||
}
|
||||
entry := h.entries[0]
|
||||
return Timer{
|
||||
timer: time.NewTimer(time.Until(entry.expiry)),
|
||||
Entry: entry,
|
||||
}
|
||||
}
|
||||
|
||||
// Timer provides a channel to block on. When the Wait channel receives an
|
||||
// item the Timer.Entry has expired. The caller is expected to call
|
||||
// ExpiryHeap.Remove with the Entry.Index().
|
||||
//
|
||||
// The caller is responsible for calling Stop to stop the timer if the timer has
|
||||
// not fired.
|
||||
type Timer struct {
|
||||
timer *time.Timer
|
||||
Entry *Entry
|
||||
}
|
||||
|
||||
func (t *Timer) Wait() <-chan time.Time {
|
||||
if t.timer == nil {
|
||||
return nil
|
||||
}
|
||||
return t.timer.C
|
||||
}
|
||||
|
||||
func (t *Timer) Stop() {
|
||||
if t.timer != nil {
|
||||
t.timer.Stop()
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,91 @@
|
|||
package ttlcache
|
||||
|
||||
import (
|
||||
"container/heap"
|
||||
"testing"
|
||||
"time"
|
||||
|
||||
"github.com/stretchr/testify/assert"
|
||||
)
|
||||
|
||||
var _ heap.Interface = (*entryHeap)(nil)
|
||||
|
||||
func TestExpiryHeap(t *testing.T) {
|
||||
h := NewExpiryHeap()
|
||||
ch := h.NotifyCh
|
||||
var entry, entry2, entry3 *Entry
|
||||
|
||||
// Init, shouldn't trigger anything
|
||||
testNoMessage(t, ch)
|
||||
|
||||
runStep(t, "add an entry", func(t *testing.T) {
|
||||
entry = h.Add("foo", 100*time.Millisecond)
|
||||
assert.Equal(t, 0, entry.heapIndex)
|
||||
testMessage(t, ch)
|
||||
testNoMessage(t, ch) // exactly one asserted above
|
||||
})
|
||||
|
||||
runStep(t, "add a second entry in front", func(t *testing.T) {
|
||||
entry2 = h.Add("bar", 50*time.Millisecond)
|
||||
assert.Equal(t, 0, entry2.heapIndex)
|
||||
assert.Equal(t, 1, entry.heapIndex)
|
||||
testMessage(t, ch)
|
||||
testNoMessage(t, ch) // exactly one asserted above
|
||||
})
|
||||
|
||||
runStep(t, "add a third entry at the end", func(t *testing.T) {
|
||||
entry3 = h.Add("baz", 1000*time.Millisecond)
|
||||
assert.Equal(t, 2, entry3.heapIndex)
|
||||
testNoMessage(t, ch) // no notify cause index 0 stayed the same
|
||||
})
|
||||
|
||||
runStep(t, "remove the first entry", func(t *testing.T) {
|
||||
h.Remove(0)
|
||||
assert.Equal(t, 0, entry.heapIndex)
|
||||
assert.Equal(t, 1, entry3.heapIndex)
|
||||
testMessage(t, ch)
|
||||
testNoMessage(t, ch)
|
||||
})
|
||||
|
||||
runStep(t, "update entry3 to expire first", func(t *testing.T) {
|
||||
h.Update(entry3.heapIndex, 10*time.Millisecond)
|
||||
assert.Equal(t, 1, entry.heapIndex)
|
||||
assert.Equal(t, 0, entry3.heapIndex)
|
||||
testMessage(t, ch)
|
||||
testNoMessage(t, ch)
|
||||
})
|
||||
|
||||
runStep(t, "0th element change triggers a notify", func(t *testing.T) {
|
||||
h.Update(entry3.heapIndex, 20)
|
||||
assert.Equal(t, 1, entry.heapIndex) // no move
|
||||
assert.Equal(t, 0, entry3.heapIndex)
|
||||
testMessage(t, ch)
|
||||
testNoMessage(t, ch) // one message
|
||||
})
|
||||
}
|
||||
|
||||
func testNoMessage(t *testing.T, ch <-chan struct{}) {
|
||||
t.Helper()
|
||||
|
||||
select {
|
||||
case <-ch:
|
||||
t.Fatal("should not have a message")
|
||||
default:
|
||||
}
|
||||
}
|
||||
|
||||
func testMessage(t *testing.T, ch <-chan struct{}) {
|
||||
t.Helper()
|
||||
|
||||
select {
|
||||
case <-ch:
|
||||
default:
|
||||
t.Fatal("should have a message")
|
||||
}
|
||||
}
|
||||
|
||||
func runStep(t *testing.T, name string, fn func(t *testing.T)) {
|
||||
if !t.Run(name, fn) {
|
||||
t.FailNow()
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue