69 lines
1.5 KiB
Go
69 lines
1.5 KiB
Go
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// Package memdb implements the "memdb" SQLite VFS.
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//
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// The "memdb" [vfs.VFS] allows the same in-memory database to be shared
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// among multiple database connections in the same process,
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// as long as the database name begins with "/".
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//
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// Importing package memdb registers the VFS:
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//
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// import _ "github.com/ncruces/go-sqlite3/vfs/memdb"
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package memdb
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import (
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"sync"
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"github.com/ncruces/go-sqlite3/vfs"
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)
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func init() {
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vfs.Register("memdb", memVFS{})
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}
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var (
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memoryMtx sync.Mutex
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// +checklocks:memoryMtx
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memoryDBs = map[string]*memDB{}
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)
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// Create creates a shared memory database,
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// using data as its initial contents.
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// The new database takes ownership of data,
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// and the caller should not use data after this call.
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func Create(name string, data []byte) {
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memoryMtx.Lock()
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defer memoryMtx.Unlock()
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db := &memDB{
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refs: 1,
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name: name,
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size: int64(len(data)),
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}
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// Convert data from WAL to rollback journal.
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if len(data) >= 20 && data[18] == 2 && data[19] == 2 {
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data[18] = 1
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data[19] = 1
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}
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sectors := divRoundUp(db.size, sectorSize)
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db.data = make([]*[sectorSize]byte, sectors)
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for i := range db.data {
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sector := data[i*sectorSize:]
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if len(sector) >= sectorSize {
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db.data[i] = (*[sectorSize]byte)(sector)
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} else {
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db.data[i] = new([sectorSize]byte)
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copy((*db.data[i])[:], sector)
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}
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}
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memoryDBs[name] = db
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}
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// Delete deletes a shared memory database.
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func Delete(name string) {
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memoryMtx.Lock()
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defer memoryMtx.Unlock()
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delete(memoryDBs, name)
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}
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