/// <summary>
/// Attempts to get the cache entry which was last stored for the given fingerprint
/// </summary>
public static async Task <Possible <CacheEntry?> > TryGetLatestCacheEntryAsync(
this ITwoPhaseFingerprintStore store,
LoggingContext loggingContext,
ContentFingerprint fingerprint,
DateTime?time = null)
{
// This method starts at a leaf time node and traverses up until a parent node
// is found which has a corresponding cache entry. Then the children of that parent
// node are iterated recursively (latest in time first) to find the node that closest in time
// to the specified time parameter. This yields the cache entry added most recently.
var node = new TimeTreeNode(time);
while (node != null)
{
var getResult = await store.TryGetTemporalCacheEntryAsync(loggingContext, node, fingerprint);
if (!getResult.Succeeded)
{
return(getResult);
}
else if (getResult.Result != null)
{
return(await TryGetLatestChildCacheEntryAsync(loggingContext, node, store, fingerprint, getResult));
}
node = node.Parent;
}
return((CacheEntry?)null);
}
public static async Task <Possible <Unit> > TryPublishTemporalCacheEntryAsync(
this ITwoPhaseFingerprintStore store,
LoggingContext loggingContext,
ContentFingerprint fingerprint,
CacheEntry entry,
DateTime?time = null)
{
// Attempt to store the cache entry into all the time buckets
var node = new TimeTreeNode(time);
var tasks = new List <Task <Possible <CacheEntryPublishResult, Failure> > >();
while (node != null)
{
tasks.Add(store.TryPublishNodeTemporalCacheEntryAsync(
loggingContext,
node,
fingerprint,
entry));
node = node.Parent;
}
await Task.WhenAll(tasks);
foreach (var task in tasks)
{
if (!task.Result.Succeeded)
{
return(task.Result.Failure);
}
}
return(Unit.Void);
}
private static async Task <Possible <CacheEntryPublishResult, Failure> > TryPublishNodeTemporalCacheEntryAsync(
this ITwoPhaseFingerprintStore store,
LoggingContext loggingContext,
TimeTreeNode node,
ContentFingerprint fingerprint,
CacheEntry entry)
{
// Unblock the caller
await Task.Yield();
var result = await store.TryPublishCacheEntryAsync(
new WeakContentFingerprint(fingerprint.Hash),
s_dummyPathSetHash,
node.NodeFingerprint,
entry);
Logger.Log.TemporalCacheEntryTrace(loggingContext, I($"Publishing temporal cache entry: Node='{node}', Fingerprint='{fingerprint}' MetadataHash='{entry.MetadataHash}' Success='{result.Succeeded}'"));
if (result.Succeeded)
{
Logger.Log.TemporalCacheEntryTrace(loggingContext, I($"Published temporal cache entry: Node='{node}', Fingerprint='{fingerprint}' Status='{result.Result.Status}'"));
}
else
{
Logger.Log.TemporalCacheEntryTrace(loggingContext, I($"Failed publish of temporal cache entry: Node='{node}', Fingerprint='{fingerprint}' Failure:='{result.Failure.DescribeIncludingInnerFailures()}'"));
}
return(result);
}
private static async Task <Possible <CacheEntry?, Failure> > TryGetTemporalCacheEntryAsync(
this ITwoPhaseFingerprintStore store,
LoggingContext loggingContext,
TimeTreeNode node,
ContentFingerprint fingerprint)
{
// Unblock the caller
await Task.Yield();
var result = await store.TryGetCacheEntryAsync(
new WeakContentFingerprint(fingerprint.Hash),
s_dummyPathSetHash,
node.NodeFingerprint);
if (result.Succeeded)
{
if (result.Result?.MetadataHash != null)
{
Logger.Log.TemporalCacheEntryTrace(loggingContext, I($"Successfully retrieved temporal cache entry: Node='{node}', Fingerprint='{fingerprint}' MetadataHash='{result.Result?.MetadataHash}'"));
}
else
{
Logger.Log.TemporalCacheEntryTrace(loggingContext, I($"Query for temporal cache entry returned no results: Node='{node}', Fingerprint='{fingerprint}'"));
}
}
else
{
Logger.Log.TemporalCacheEntryTrace(loggingContext, I($"Failed retrieval of temporal cache entry: Node='{node}', Fingerprint='{fingerprint}' Failure:='{result.Failure.DescribeIncludingInnerFailures()}'"));
}
return(result);
}
public static async Task <Possible <Unit> > TryPublishTemporalCacheEntryAsync(
this ITwoPhaseFingerprintStore store,
LoggingContext loggingContext,
ContentFingerprint fingerprint,
CacheEntry entry,
DateTime?time = null)
{
// Attempt to store the cache entry into all the time buckets
var node = new TimeTreeNode(time);
var tasks = new List <Task <Possible <CacheEntryPublishResult, Failure> > >();
while (node != null)
{
tasks.Add(store.TryPublishNodeTemporalCacheEntryAsync(
loggingContext,
node,
fingerprint,
entry));
// Don't store full cache entry for parent nodes since time tree addition
// will trigger pins (and consequently downloads) of content for conflicting entries
entry = new CacheEntry(entry.MetadataHash, entry.OriginatingCache, ArrayView <ContentHash> .Empty);
node = node.Parent;
}
await Task.WhenAll(tasks);
foreach (var task in tasks)
{
if (!task.Result.Succeeded)
{
return(task.Result.Failure);
}
}
return(Unit.Void);
}
/// <summary>
/// Attempts to get the cache entry for the child which comes latest in time
/// </summary>
private static async Task <Possible <CacheEntry?> > TryGetLatestChildCacheEntryAsync(
LoggingContext loggingContext,
TimeTreeNode node,
ITwoPhaseFingerprintStore store,
ContentFingerprint fingerprint,
Possible <CacheEntry?> fallbackResult)
{
var childNodes = node.Children;
var children = childNodes.Select(childNode => store.TryGetTemporalCacheEntryAsync(loggingContext, childNode, fingerprint)).ToList();
var childResults = await Task.WhenAll(children);
// In reverse order (i.e. later in time), check children to see which
// one has results
for (int i = childResults.Length - 1; i >= 0; i--)
{
var childResult = childResults[i];
var childNode = childNodes[i];
if (!childResult.Succeeded)
{
continue;
}
if (childResult.Result != null)
{
return(await TryGetLatestChildCacheEntryAsync(
loggingContext,
childNode,
store,
fingerprint,
childResult));
}
}
return(fallbackResult);
}