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Merge pull request #777 from tjungblu/freelist_first_array
move array related freelist functions into own file
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,98 @@ | ||
| package bbolt | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "sort" | ||
|
|
||
| "go.etcd.io/bbolt/internal/common" | ||
| ) | ||
|
|
||
| // arrayFreeCount returns count of free pages(array version) | ||
| func (f *freelist) arrayFreeCount() int { | ||
| return len(f.ids) | ||
| } | ||
|
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| // arrayAllocate returns the starting page id of a contiguous list of pages of a given size. | ||
| // If a contiguous block cannot be found then 0 is returned. | ||
| func (f *freelist) arrayAllocate(txid common.Txid, n int) common.Pgid { | ||
| if len(f.ids) == 0 { | ||
| return 0 | ||
| } | ||
|
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| var initial, previd common.Pgid | ||
| for i, id := range f.ids { | ||
| if id <= 1 { | ||
| panic(fmt.Sprintf("invalid page allocation: %d", id)) | ||
| } | ||
|
|
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| // Reset initial page if this is not contiguous. | ||
| if previd == 0 || id-previd != 1 { | ||
| initial = id | ||
| } | ||
|
|
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| // If we found a contiguous block then remove it and return it. | ||
| if (id-initial)+1 == common.Pgid(n) { | ||
| // If we're allocating off the beginning then take the fast path | ||
| // and just adjust the existing slice. This will use extra memory | ||
| // temporarily but the append() in free() will realloc the slice | ||
| // as is necessary. | ||
| if (i + 1) == n { | ||
| f.ids = f.ids[i+1:] | ||
| } else { | ||
| copy(f.ids[i-n+1:], f.ids[i+1:]) | ||
| f.ids = f.ids[:len(f.ids)-n] | ||
| } | ||
|
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||
| // Remove from the free cache. | ||
| for i := common.Pgid(0); i < common.Pgid(n); i++ { | ||
| delete(f.cache, initial+i) | ||
| } | ||
| f.allocs[initial] = txid | ||
| return initial | ||
| } | ||
|
|
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| previd = id | ||
| } | ||
| return 0 | ||
| } | ||
|
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| // arrayReadIDs initializes the freelist from a given list of ids. | ||
| func (f *freelist) arrayReadIDs(ids []common.Pgid) { | ||
| f.ids = ids | ||
| f.reindex() | ||
| } | ||
|
|
||
| func (f *freelist) arrayGetFreePageIDs() []common.Pgid { | ||
| return f.ids | ||
| } | ||
|
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| // arrayMergeSpans try to merge list of pages(represented by pgids) with existing spans but using array | ||
| func (f *freelist) arrayMergeSpans(ids common.Pgids) { | ||
| sort.Sort(ids) | ||
| common.Verify(func() { | ||
| idsIdx := make(map[common.Pgid]struct{}) | ||
| for _, id := range f.ids { | ||
| // The existing f.ids shouldn't have duplicated free ID. | ||
| if _, ok := idsIdx[id]; ok { | ||
| panic(fmt.Sprintf("detected duplicated free page ID: %d in existing f.ids: %v", id, f.ids)) | ||
| } | ||
| idsIdx[id] = struct{}{} | ||
| } | ||
|
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||
| prev := common.Pgid(0) | ||
| for _, id := range ids { | ||
| // The ids shouldn't have duplicated free ID. Note page 0 and 1 | ||
| // are reserved for meta pages, so they can never be free page IDs. | ||
| if prev == id { | ||
| panic(fmt.Sprintf("detected duplicated free ID: %d in ids: %v", id, ids)) | ||
| } | ||
| prev = id | ||
|
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| // The ids shouldn't have any overlap with the existing f.ids. | ||
| if _, ok := idsIdx[id]; ok { | ||
| panic(fmt.Sprintf("detected overlapped free page ID: %d between ids: %v and existing f.ids: %v", id, ids, f.ids)) | ||
| } | ||
| } | ||
| }) | ||
| f.ids = common.Pgids(f.ids).Merge(ids) | ||
| } |