mirror of https://github.com/hak5/bolt.git
Remove RWCursor.
Ben Johnson
parent
73ab1d420d
commit
2c6b8e0ebf
56
README.md
56
README.md
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@ -98,10 +98,36 @@ buckets, err := db.Buckets()
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```
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### Key/Value Access
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#### Retrieve a value for a specific key
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```go
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t, err := db.Transaction()
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value, err := t.Get("widgets", []byte("foo"))
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value, err := t.GetString("widgets", "foo")
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```
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#### Set the value for a key
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```go
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t, err := db.RWTransaction()
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err := t.Put("widgets", []byte("foo"), []byte("bar"))
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err := t.PutString("widgets", "foo", "bar")
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```
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#### Delete a given key
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```go
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t, err := db.RWTransaction()
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err := t.Delete("widgets", []byte("foo"))
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err := t.DeleteString("widgets", "foo")
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```
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### Cursors
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Cursors provide access to a specific bucket within a transaction.
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Cursors provide fast read-only access to a specific bucket within a transaction.
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#### Creating a read-only cursor
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@ -111,13 +137,6 @@ t, err := db.Transaction()
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c, err := b.Cursor("widgets")
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```
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#### Creating a read/write cursor
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```go
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t, err := db.RWTransaction()
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c, err := t.RWCursor("widgets")
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```
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#### Iterating over a cursor
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```go
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@ -129,27 +148,6 @@ for k, v, err := c.First(); k != nil; k, v, err = c.Next() {
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}
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```
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#### Retrieve a value for a specific key
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```go
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value, err := c.Get([]byte("foo"))
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value, err := c.GetString("foo")
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```
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#### Set the value for a key (RWCursor only)
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```go
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err := c.Put([]byte("foo"), []byte("bar"))
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err := c.PutString("foo", "bar")
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```
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#### Delete a given key
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```go
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err := c.Delete([]byte("foo"))
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err := c.DeleteString("foo")
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```
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## Internals
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106
rwcursor.go
106
rwcursor.go
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@ -1,106 +0,0 @@
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package bolt
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// RWCursor represents a cursor that can read and write data for a bucket.
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type RWCursor struct {
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Cursor
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transaction *RWTransaction
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}
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func (c *RWCursor) Put(key []byte, value []byte) error {
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// Make sure this cursor was created by a transaction.
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if c.transaction == nil {
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return &Error{"invalid cursor", nil}
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}
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db := c.transaction.db
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// Validate the key we're using.
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if key == nil {
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return &Error{"key required", nil}
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} else if len(key) > db.maxKeySize {
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return &Error{"key too large", nil}
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}
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// TODO: Validate data size based on MaxKeySize if DUPSORT.
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// Validate the size of our data.
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if len(data) > MaxDataSize {
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return &Error{"data too large", nil}
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}
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// If we don't have a root page then add one.
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if c.bucket.root == p_invalid {
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p, err := c.newLeafPage()
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if err != nil {
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return err
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}
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c.push(p)
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c.bucket.root = p.id
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c.bucket.root++
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// TODO: *mc->mc_dbflag |= DB_DIRTY;
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// TODO? mc->mc_flags |= C_INITIALIZED;
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}
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// TODO: Move to key.
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exists, err := c.moveTo(key)
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if err != nil {
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return err
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}
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// TODO: spill?
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if err := c.spill(key, data); err != nil {
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return err
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}
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// Make sure all cursor pages are writable
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if err := c.touch(); err != nil {
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return err
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}
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// If key does not exist the
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if exists {
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node := c.currentNode()
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}
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return nil
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}
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func (c *Cursor) Delete(key []byte) error {
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// TODO: Traverse to the correct node.
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// TODO: If missing, exit.
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// TODO: Remove node from page.
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// TODO: If page is empty then add it to the freelist.
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return nil
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}
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// newLeafPage allocates and initialize new a new leaf page.
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func (c *RWCursor) newLeafPage() (*page, error) {
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// Allocate page.
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p, err := c.allocatePage(1)
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if err != nil {
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return nil, err
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}
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// Set flags and bounds.
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p.flags = p_leaf | p_dirty
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p.lower = pageHeaderSize
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p.upper = c.transaction.db.pageSize
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return p, nil
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}
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// newBranchPage allocates and initialize new a new branch page.
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func (b *RWCursor) newBranchPage() (*page, error) {
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// Allocate page.
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p, err := c.allocatePage(1)
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if err != nil {
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return nil, err
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}
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// Set flags and bounds.
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p.flags = p_branch | p_dirty
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p.lower = pageHeaderSize
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p.upper = c.transaction.db.pageSize
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return p, nil
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}
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@ -127,6 +127,105 @@ func (t *RWTransaction) DeleteBucket(name string) error {
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return nil
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}
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func (c *RWCursor) Put(key []byte, value []byte) error {
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// Make sure this cursor was created by a transaction.
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if c.transaction == nil {
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return &Error{"invalid cursor", nil}
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}
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db := c.transaction.db
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// Validate the key we're using.
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if key == nil {
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return &Error{"key required", nil}
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} else if len(key) > db.maxKeySize {
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return &Error{"key too large", nil}
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}
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// TODO: Validate data size based on MaxKeySize if DUPSORT.
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// Validate the size of our data.
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if len(data) > MaxDataSize {
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return &Error{"data too large", nil}
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}
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// If we don't have a root page then add one.
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if c.bucket.root == p_invalid {
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p, err := c.newLeafPage()
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if err != nil {
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return err
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}
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c.push(p)
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c.bucket.root = p.id
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c.bucket.root++
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// TODO: *mc->mc_dbflag |= DB_DIRTY;
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// TODO? mc->mc_flags |= C_INITIALIZED;
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}
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// TODO: Move to key.
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exists, err := c.moveTo(key)
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if err != nil {
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return err
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}
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// TODO: spill?
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if err := c.spill(key, data); err != nil {
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return err
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}
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// Make sure all cursor pages are writable
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if err := c.touch(); err != nil {
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return err
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}
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// If key does not exist the
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if exists {
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node := c.currentNode()
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}
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return nil
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}
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func (c *Cursor) Delete(key []byte) error {
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// TODO: Traverse to the correct node.
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// TODO: If missing, exit.
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// TODO: Remove node from page.
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// TODO: If page is empty then add it to the freelist.
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return nil
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}
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// newLeafPage allocates and initialize new a new leaf page.
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func (c *RWCursor) newLeafPage() (*page, error) {
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// Allocate page.
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p, err := c.allocatePage(1)
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if err != nil {
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return nil, err
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}
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// Set flags and bounds.
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p.flags = p_leaf | p_dirty
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p.lower = pageHeaderSize
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p.upper = c.transaction.db.pageSize
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return p, nil
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}
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// newBranchPage allocates and initialize new a new branch page.
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func (b *RWCursor) newBranchPage() (*page, error) {
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// Allocate page.
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p, err := c.allocatePage(1)
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if err != nil {
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return nil, err
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}
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// Set flags and bounds.
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p.flags = p_branch | p_dirty
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p.lower = pageHeaderSize
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p.upper = c.transaction.db.pageSize
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return p, nil
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}
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// allocate returns a contiguous block of memory starting at a given page.
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func (t *RWTransaction) allocate(count int) (*page, error) {
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// TODO: Find a continuous block of free pages.
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