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package fzf
import "sync"
// Chunk is a list of Item pointers whose size has the upper limit of chunkSize
type Chunk []*Item // >>> []Item
// ItemBuilder is a closure type that builds Item object from a pointer to a
// string and an integer
type ItemBuilder func([]byte, int) *Item
// ChunkList is a list of Chunks
type ChunkList struct {
chunks []*Chunk
count int
mutex sync.Mutex
trans ItemBuilder
}
// NewChunkList returns a new ChunkList
func NewChunkList(trans ItemBuilder) *ChunkList {
return &ChunkList{
chunks: []*Chunk{},
count: 0,
mutex: sync.Mutex{},
trans: trans}
}
func (c *Chunk) push(trans ItemBuilder, data []byte, index int) bool {
item := trans(data, index)
if item != nil {
*c = append(*c, item)
return true
}
return false
}
// IsFull returns true if the Chunk is full
func (c *Chunk) IsFull() bool {
return len(*c) == chunkSize
}
func (cl *ChunkList) lastChunk() *Chunk {
return cl.chunks[len(cl.chunks)-1]
}
// CountItems returns the total number of Items
func CountItems(cs []*Chunk) int {
if len(cs) == 0 {
return 0
}
return chunkSize*(len(cs)-1) + len(*(cs[len(cs)-1]))
}
// Push adds the item to the list
func (cl *ChunkList) Push(data []byte) bool {
cl.mutex.Lock()
defer cl.mutex.Unlock()
if len(cl.chunks) == 0 || cl.lastChunk().IsFull() {
newChunk := Chunk(make([]*Item, 0, chunkSize))
cl.chunks = append(cl.chunks, &newChunk)
}
if cl.lastChunk().push(cl.trans, data, cl.count) {
cl.count++
return true
}
return false
}
// Snapshot returns immutable snapshot of the ChunkList
func (cl *ChunkList) Snapshot() ([]*Chunk, int) {
cl.mutex.Lock()
defer cl.mutex.Unlock()
ret := make([]*Chunk, len(cl.chunks))
copy(ret, cl.chunks)
// Duplicate the last chunk
if cnt := len(ret); cnt > 0 {
ret[cnt-1] = ret[cnt-1].dupe()
}
return ret, cl.count
}
func (c *Chunk) dupe() *Chunk {
newChunk := make(Chunk, len(*c))
for idx, ptr := range *c {
newChunk[idx] = ptr
}
return &newChunk
}
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