viewPending = "(not summarized yet: zoom it)"
)
-// newView returns an empty view with the limits high and low.
-func newView(high, low int) *View {
- return &View{
- high: high,
- low: low,
- nodes: make(map[NodeKey]Node),
- }
-}
-
-// restoreView returns the view of state with the limits high and low. Each line
-// must continue the one before it, and each line above level 0 must be built.
-func restoreView(state ViewState, high, low int, tree ViewNodeReader) (*View, error) {
- v := newView(high, low)
- v.merging = state.Merging
- for _, pair := range state.Lines {
- line := NodeKey{pair[0], pair[1]}
- if line.level < 0 || line.level >= bits.UintSize-2 || line.index < 0 || line.index<<line.level != v.end {
- return nil, fmt.Errorf("view line (%d, %d) does not start at message %d", line.level, line.index, v.end)
- }
-
- built, err := v.load(tree, line)
- if err != nil {
- return nil, err
- }
-
- if line.level > 0 && !built {
- return nil, fmt.Errorf("view line (%d, %d) is not built", line.level, line.index)
- }
-
- v.lines = append(v.lines, line)
- v.end = nodeEnd(line.level, line.index)
- }
-
- return v, nil
-}
-
// View is a list of tree nodes that covers messages 0 to end-1 without a gap,
// oldest first. Each new message appends its leaf as a line. Once the size of
// the view goes above high, one batch merges the most due sibling pairs until
merging bool
}
+// ViewState is the saved form of a View. The limits are not part of it.
+type ViewState struct {
+ Lines [][2]int `json:"lines"`
+ Merging bool `json:"merging"`
+}
+
+// ViewNodeReader gives the built nodes of a tree.
+type ViewNodeReader interface {
+ Built(level, index int) (bool, error)
+ Node(level, index int) (Node, bool, error)
+}
+
+// newView returns an empty view with the limits high and low.
+func newView(high, low int) *View {
+ return &View{
+ high: high,
+ low: low,
+ nodes: make(map[NodeKey]Node),
+ }
+}
+
// State returns the saved form of the view.
func (v *View) State() ViewState {
state := ViewState{
return v.fit(tree)
}
+// load keeps the node of line when it is built, and tells if it is.
+func (v *View) load(tree ViewNodeReader, line NodeKey) (bool, error) {
+ node, built, err := tree.Node(line.level, line.index)
+ if err != nil || !built {
+ return false, err
+ }
+
+ v.nodes[line] = node
+
+ return true, nil
+}
+
+// fit merges the most due pairs while a batch runs, and tells if a merge
+// changed the view.
+func (v *View) fit(tree ViewNodeReader) (bool, error) {
+ size := v.Size()
+ if size > v.high {
+ v.merging = true
+ }
+
+ merged := false
+ for v.merging && size > v.low {
+ best, err := v.mostDue(tree)
+ if err != nil || best < 0 {
+ return merged, err
+ }
+
+ left, right := v.lines[best], v.lines[best+1]
+ parent := NodeKey{left.level + 1, left.index / 2}
+ _, err = v.load(tree, parent)
+ if err != nil {
+ return merged, err
+ }
+
+ size += v.lineSize(parent) - v.lineSize(left) - v.lineSize(right)
+ delete(v.nodes, left)
+ delete(v.nodes, right)
+
+ v.lines[best] = parent
+ v.lines = append(v.lines[:best+1], v.lines[best+2:]...)
+ merged = true
+ }
+
+ v.merging = false
+
+ return merged, nil
+}
+
+// Size returns the sum of the line sizes.
+func (v *View) Size() int {
+ size := 0
+ for _, line := range v.lines {
+ size += v.lineSize(line)
+ }
+
+ return size
+}
+
+// mostDue returns the position of the left line of the most due sibling pair
+// whose parent is built, or -1 when there is no such pair.
+func (v *View) mostDue(tree ViewNodeReader) (int, error) {
+ best := -1
+ bestDue := 0.0
+ for n := 0; n+1 < len(v.lines); n++ {
+ left, right := v.lines[n], v.lines[n+1]
+ if left.index%2 != 0 || right.level != left.level || right.index != left.index+1 {
+ continue
+ }
+
+ last := nodeEnd(right.level, right.index) - 1
+ due := math.Ldexp(float64(v.end-last), -left.level)
+ if best >= 0 && due <= bestDue {
+ continue
+ }
+
+ built, err := tree.Built(left.level+1, left.index/2)
+ if err != nil {
+ return -1, fmt.Errorf("check parent node: %w", err)
+ }
+
+ if built {
+ best = n
+ bestDue = due
+ }
+ }
+
+ return best, nil
+}
+
+// lineSize returns the size of a view line.
+func (v *View) lineSize(line NodeKey) int {
+ node, built := v.nodes[line]
+ if !built {
+ return len(viewPending)
+ }
+
+ return node.Size
+}
+
// Coarsen takes each merge of other, a view of the same messages, and then
// merges in one batch until the size is at most low. Each line of the result is
// the coarser of the two lines that start at its first message. Dyadic ranges
return lines
}
+// renderLine writes one view line, "id+n|text", and a newline.
+func (v *View) renderLine(text *strings.Builder, line NodeKey) {
+ body := viewPending
+ node, built := v.nodes[line]
+ if built {
+ body = strings.ReplaceAll(node.Text, "\n", " ")
+ }
+
+ text.WriteString(strconv.Itoa(line.index << line.level))
+ text.WriteByte('+')
+ text.WriteString(strconv.Itoa(1 << line.level))
+ text.WriteByte('|')
+ text.WriteString(body)
+ text.WriteByte('\n')
+}
+
// Context returns the lines of the view before message end as the model reads
// them. It stops at the first line that is not built, so a compaction never
// sees a pending mark or a part of a message.
return text.String()
}
-// load keeps the node of line when it is built, and tells if it is.
-func (v *View) load(tree ViewNodeReader, line NodeKey) (bool, error) {
- node, built, err := tree.Node(line.level, line.index)
- if err != nil || !built {
- return false, err
- }
-
- v.nodes[line] = node
-
- return true, nil
-}
-
-// fit merges the most due pairs while a batch runs, and tells if a merge
-// changed the view.
-func (v *View) fit(tree ViewNodeReader) (bool, error) {
- size := v.Size()
- if size > v.high {
- v.merging = true
- }
-
- merged := false
- for v.merging && size > v.low {
- best, err := v.mostDue(tree)
- if err != nil || best < 0 {
- return merged, err
- }
-
- left, right := v.lines[best], v.lines[best+1]
- parent := NodeKey{left.level + 1, left.index / 2}
- _, err = v.load(tree, parent)
- if err != nil {
- return merged, err
- }
-
- size += v.lineSize(parent) - v.lineSize(left) - v.lineSize(right)
- delete(v.nodes, left)
- delete(v.nodes, right)
-
- v.lines[best] = parent
- v.lines = append(v.lines[:best+1], v.lines[best+2:]...)
- merged = true
- }
-
- v.merging = false
-
- return merged, nil
-}
-
-// renderLine writes one view line, "id+n|text", and a newline.
-func (v *View) renderLine(text *strings.Builder, line NodeKey) {
- body := viewPending
- node, built := v.nodes[line]
- if built {
- body = strings.ReplaceAll(node.Text, "\n", " ")
- }
-
- text.WriteString(strconv.Itoa(line.index << line.level))
- text.WriteByte('+')
- text.WriteString(strconv.Itoa(1 << line.level))
- text.WriteByte('|')
- text.WriteString(body)
- text.WriteByte('\n')
-}
-
-// Size returns the sum of the line sizes.
-func (v *View) Size() int {
- size := 0
- for _, line := range v.lines {
- size += v.lineSize(line)
- }
-
- return size
-}
-
-// mostDue returns the position of the left line of the most due sibling pair
-// whose parent is built, or -1 when there is no such pair.
-func (v *View) mostDue(tree ViewNodeReader) (int, error) {
- best := -1
- bestDue := 0.0
- for n := 0; n+1 < len(v.lines); n++ {
- left, right := v.lines[n], v.lines[n+1]
- if left.index%2 != 0 || right.level != left.level || right.index != left.index+1 {
- continue
- }
-
- last := nodeEnd(right.level, right.index) - 1
- due := math.Ldexp(float64(v.end-last), -left.level)
- if best >= 0 && due <= bestDue {
- continue
+// restoreView returns the view of state with the limits high and low. Each line
+// must continue the one before it, and each line above level 0 must be built.
+func restoreView(state ViewState, high, low int, tree ViewNodeReader) (*View, error) {
+ v := newView(high, low)
+ v.merging = state.Merging
+ for _, pair := range state.Lines {
+ line := NodeKey{pair[0], pair[1]}
+ if line.level < 0 || line.level >= bits.UintSize-2 || line.index < 0 || line.index<<line.level != v.end {
+ return nil, fmt.Errorf("view line (%d, %d) does not start at message %d", line.level, line.index, v.end)
}
- built, err := tree.Built(left.level+1, left.index/2)
+ built, err := v.load(tree, line)
if err != nil {
- return -1, fmt.Errorf("check parent node: %w", err)
+ return nil, err
}
- if built {
- best = n
- bestDue = due
+ if line.level > 0 && !built {
+ return nil, fmt.Errorf("view line (%d, %d) is not built", line.level, line.index)
}
- }
- return best, nil
-}
-
-// lineSize returns the size of a view line.
-func (v *View) lineSize(line NodeKey) int {
- node, built := v.nodes[line]
- if !built {
- return len(viewPending)
+ v.lines = append(v.lines, line)
+ v.end = nodeEnd(line.level, line.index)
}
- return node.Size
-}
-
-// ViewState is the saved form of a View. The limits are not part of it.
-type ViewState struct {
- Lines [][2]int `json:"lines"`
- Merging bool `json:"merging"`
-}
-
-// ViewNodeReader gives the built nodes of a tree.
-type ViewNodeReader interface {
- Built(level, index int) (bool, error)
- Node(level, index int) (Node, bool, error)
+ return v, nil
}
projects / onechat / blobdiff