cmd, core, eth, light, trie: add trie read caching layer

vendor/github.com/allegro/bigcache/config.go

@@ -0,0 +1,86 @@
+package bigcache
+
+import "time"
+
+// Config for BigCache
+type Config struct {
+	// Number of cache shards, value must be a power of two
+	Shards int
+	// Time after which entry can be evicted
+	LifeWindow time.Duration
+	// Interval between removing expired entries (clean up).
+	// If set to <= 0 then no action is performed. Setting to < 1 second is counterproductive — bigcache has a one second resolution.
+	CleanWindow time.Duration
+	// Max number of entries in life window. Used only to calculate initial size for cache shards.
+	// When proper value is set then additional memory allocation does not occur.
+	MaxEntriesInWindow int
+	// Max size of entry in bytes. Used only to calculate initial size for cache shards.
+	MaxEntrySize int
+	// Verbose mode prints information about new memory allocation
+	Verbose bool
+	// Hasher used to map between string keys and unsigned 64bit integers, by default fnv64 hashing is used.
+	Hasher Hasher
+	// HardMaxCacheSize is a limit for cache size in MB. Cache will not allocate more memory than this limit.
+	// It can protect application from consuming all available memory on machine, therefore from running OOM Killer.
+	// Default value is 0 which means unlimited size. When the limit is higher than 0 and reached then
+	// the oldest entries are overridden for the new ones.
+	HardMaxCacheSize int
+	// OnRemove is a callback fired when the oldest entry is removed because of its expiration time or no space left
+	// for the new entry, or because delete was called.
+	// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
+	OnRemove func(key string, entry []byte)
+	// OnRemoveWithReason is a callback fired when the oldest entry is removed because of its expiration time or no space left
+	// for the new entry, or because delete was called. A constant representing the reason will be passed through.
+	// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
+	// Ignored if OnRemove is specified.
+	OnRemoveWithReason func(key string, entry []byte, reason RemoveReason)
+
+	onRemoveFilter int
+
+	// Logger is a logging interface and used in combination with `Verbose`
+	// Defaults to `DefaultLogger()`
+	Logger Logger
+}
+
+// DefaultConfig initializes config with default values.
+// When load for BigCache can be predicted in advance then it is better to use custom config.
+func DefaultConfig(eviction time.Duration) Config {
+	return Config{
+		Shards:             1024,
+		LifeWindow:         eviction,
+		CleanWindow:        0,
+		MaxEntriesInWindow: 1000 * 10 * 60,
+		MaxEntrySize:       500,
+		Verbose:            true,
+		Hasher:             newDefaultHasher(),
+		HardMaxCacheSize:   0,
+		Logger:             DefaultLogger(),
+	}
+}
+
+// initialShardSize computes initial shard size
+func (c Config) initialShardSize() int {
+	return max(c.MaxEntriesInWindow/c.Shards, minimumEntriesInShard)
+}
+
+// maximumShardSize computes maximum shard size
+func (c Config) maximumShardSize() int {
+	maxShardSize := 0
+
+	if c.HardMaxCacheSize > 0 {
+		maxShardSize = convertMBToBytes(c.HardMaxCacheSize) / c.Shards
+	}
+
+	return maxShardSize
+}
+
+// OnRemoveFilterSet sets which remove reasons will trigger a call to OnRemoveWithReason.
+// Filtering out reasons prevents bigcache from unwrapping them, which saves cpu.
+func (c Config) OnRemoveFilterSet(reasons ...RemoveReason) Config {
+	c.onRemoveFilter = 0
+	for i := range reasons {
+		c.onRemoveFilter |= 1 << uint(reasons[i])
+	}
+
+	return c
+}