[VOL-2831] - Multiple adapter support
This commit introduces the necessary APIs needed to support
multiple adapters. It uses the number of replicas of a given
adapter and consistent hashing to determine the target of a
given request.
The endpoint_manager.go provides two APIs that will be needed
by components communicating over kafka:
- GetEndPoint() : to be called before sending a request to kafka
- IsDeviceOwnedByService(): used during device reconciliation
A change is made to the adapter_proxy.go to use this new mechanism
when sending a request to an adapter from another adapter.
The mocks directory was refactored to get around circular package
dependencies. This implies any component using these mocks will
need to adjust to the new set of directories when using this
library version.
Change-Id: I470cd62fcfd04edc1fd4508400c9619cadaab25a
diff --git a/vendor/github.com/cespare/xxhash/xxhash.go b/vendor/github.com/cespare/xxhash/xxhash.go
new file mode 100644
index 0000000..f896bd2
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/xxhash.go
@@ -0,0 +1,168 @@
+// Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
+// at http://cyan4973.github.io/xxHash/.
+package xxhash
+
+import (
+ "encoding/binary"
+ "hash"
+)
+
+const (
+ prime1 uint64 = 11400714785074694791
+ prime2 uint64 = 14029467366897019727
+ prime3 uint64 = 1609587929392839161
+ prime4 uint64 = 9650029242287828579
+ prime5 uint64 = 2870177450012600261
+)
+
+// NOTE(caleb): I'm using both consts and vars of the primes. Using consts where
+// possible in the Go code is worth a small (but measurable) performance boost
+// by avoiding some MOVQs. Vars are needed for the asm and also are useful for
+// convenience in the Go code in a few places where we need to intentionally
+// avoid constant arithmetic (e.g., v1 := prime1 + prime2 fails because the
+// result overflows a uint64).
+var (
+ prime1v = prime1
+ prime2v = prime2
+ prime3v = prime3
+ prime4v = prime4
+ prime5v = prime5
+)
+
+type xxh struct {
+ v1 uint64
+ v2 uint64
+ v3 uint64
+ v4 uint64
+ total int
+ mem [32]byte
+ n int // how much of mem is used
+}
+
+// New creates a new hash.Hash64 that implements the 64-bit xxHash algorithm.
+func New() hash.Hash64 {
+ var x xxh
+ x.Reset()
+ return &x
+}
+
+func (x *xxh) Reset() {
+ x.n = 0
+ x.total = 0
+ x.v1 = prime1v + prime2
+ x.v2 = prime2
+ x.v3 = 0
+ x.v4 = -prime1v
+}
+
+func (x *xxh) Size() int { return 8 }
+func (x *xxh) BlockSize() int { return 32 }
+
+// Write adds more data to x. It always returns len(b), nil.
+func (x *xxh) Write(b []byte) (n int, err error) {
+ n = len(b)
+ x.total += len(b)
+
+ if x.n+len(b) < 32 {
+ // This new data doesn't even fill the current block.
+ copy(x.mem[x.n:], b)
+ x.n += len(b)
+ return
+ }
+
+ if x.n > 0 {
+ // Finish off the partial block.
+ copy(x.mem[x.n:], b)
+ x.v1 = round(x.v1, u64(x.mem[0:8]))
+ x.v2 = round(x.v2, u64(x.mem[8:16]))
+ x.v3 = round(x.v3, u64(x.mem[16:24]))
+ x.v4 = round(x.v4, u64(x.mem[24:32]))
+ b = b[32-x.n:]
+ x.n = 0
+ }
+
+ if len(b) >= 32 {
+ // One or more full blocks left.
+ b = writeBlocks(x, b)
+ }
+
+ // Store any remaining partial block.
+ copy(x.mem[:], b)
+ x.n = len(b)
+
+ return
+}
+
+func (x *xxh) Sum(b []byte) []byte {
+ s := x.Sum64()
+ return append(
+ b,
+ byte(s>>56),
+ byte(s>>48),
+ byte(s>>40),
+ byte(s>>32),
+ byte(s>>24),
+ byte(s>>16),
+ byte(s>>8),
+ byte(s),
+ )
+}
+
+func (x *xxh) Sum64() uint64 {
+ var h uint64
+
+ if x.total >= 32 {
+ v1, v2, v3, v4 := x.v1, x.v2, x.v3, x.v4
+ h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
+ h = mergeRound(h, v1)
+ h = mergeRound(h, v2)
+ h = mergeRound(h, v3)
+ h = mergeRound(h, v4)
+ } else {
+ h = x.v3 + prime5
+ }
+
+ h += uint64(x.total)
+
+ i, end := 0, x.n
+ for ; i+8 <= end; i += 8 {
+ k1 := round(0, u64(x.mem[i:i+8]))
+ h ^= k1
+ h = rol27(h)*prime1 + prime4
+ }
+ if i+4 <= end {
+ h ^= uint64(u32(x.mem[i:i+4])) * prime1
+ h = rol23(h)*prime2 + prime3
+ i += 4
+ }
+ for i < end {
+ h ^= uint64(x.mem[i]) * prime5
+ h = rol11(h) * prime1
+ i++
+ }
+
+ h ^= h >> 33
+ h *= prime2
+ h ^= h >> 29
+ h *= prime3
+ h ^= h >> 32
+
+ return h
+}
+
+func u64(b []byte) uint64 { return binary.LittleEndian.Uint64(b) }
+func u32(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
+
+func round(acc, input uint64) uint64 {
+ acc += input * prime2
+ acc = rol31(acc)
+ acc *= prime1
+ return acc
+}
+
+func mergeRound(acc, val uint64) uint64 {
+ val = round(0, val)
+ acc ^= val
+ acc = acc*prime1 + prime4
+ return acc
+}