Reflow comments over the reflow width

[onechat] / view.go

diff --git a/view.go b/view.go
index ddd97ed55f404e0a8b6ede25ea3ffccbe4883b57..235719877517ad1cbce460dfa18ccb3c07af5366 100644 (file)
--- a/view.go
+++ b/view.go
@@ -9,72 +9,45 @@ import (
 )
 
 const (
 )
 
 const (

-       // chatHigh and chatLow are the limits of the chat view in bytes.
-       chatHigh = 128000
-       chatLow  = 64000
-
-       // compactionHigh and compactionLow are the limits of the compaction
-       // view in bytes.
-       compactionHigh = 32000
-       compactionLow  = 16000
-
-       // pending is the text of a line that is not built yet.
-       pending = "(not summarized yet: zoom it)"
+       // viewChatHigh and viewChatLow are the limits of the chat view in
+       // bytes.
+       viewChatHigh = 128000
+       viewChatLow  = 64000
+
+       // viewCompactionHigh and viewCompactionLow are the limits of the
+       // compaction view in bytes.
+       viewCompactionHigh = 32000
+       viewCompactionLow  = 16000
+
+       // viewPending is the text of a line that is not built yet.
+       viewPending = "(not summarized yet: zoom it)"

 )
 
 )
 

-// nodeReader gives the built nodes of a tree.
-type nodeReader interface {
-       Node(level, index int) (Node, bool)
-}
-
-// 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
-// the size is at most low. A batch merges only pairs whose parent is built. If
-// the batch cannot get to low, it continues at each new message until it does.
-//
-// The size of a line is the size of its node text, or the size of the pending
-// text when the node is not built.
-//
-// For the sibling pair (l, i) and (l, i+1), due is (T - last) / 2^l, with T the
-// number of messages and last the ID of the last message of the pair. That is
-// how long ago the pair ended, measured in its own line size. With a budget of
-// the length of Taelin's rollback push list, this order makes the same merges
-// as the push. The oldest pair wins a tie.
-type View struct {
-       high    int
-       low     int
-       lines   []nodeKey
-       end     int
-       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"`
-}
-

 // newView returns an empty view with the limits high and low.
 func newView(high, low int) *View {
        return &View{
 // newView returns an empty view with the limits high and low.
 func newView(high, low int) *View {
        return &View{

-               high: high,
-               low:  low,
+               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.
        }
 }
 
 // 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 nodeReader) (*View, error) {
+func restoreView(state ViewState, high, low int, tree ViewNodeReader) (*View, error) {

        v := newView(high, low)
        v.merging = state.Merging
        for _, pair := range state.Lines {
        v := newView(high, low)
        v.merging = state.Merging
        for _, pair := range state.Lines {

-               line := nodeKey{pair[0], pair[1]}
+               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)
                }
 
                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 := tree.Node(line.level, line.index)
+               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)
                }
                if line.level > 0 && !built {
                        return nil, fmt.Errorf("view line (%d, %d) is not built", line.level, line.index)
                }


@@ -86,9 +59,33 @@ func restoreView(state viewState, high, low int, tree nodeReader) (*View, error)
        return v, nil
 }
 
        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
+// the size is at most low. A batch merges only pairs whose parent is built. If
+// the batch cannot get to low, it continues at each new message until it does.
+//
+// The view keeps the nodes of its built lines in memory, so its size and its
+// text need no read of the tree. The size of a line is the size of its node
+// text, or the size of the pending text when the node is not built.
+//
+// For the sibling pair (l, i) and (l, i+1), due is (T - last) / 2^l, with T the
+// number of messages and last the ID of the last message of the pair. That is
+// how long ago the pair ended, measured in its own line size. With a budget of
+// the length of the rollback push list of the reference design, this order
+// makes the same merges as the push. The oldest pair wins a tie.
+type View struct {
+       high    int
+       low     int
+       lines   []NodeKey
+       nodes   map[NodeKey]Node
+       end     int
+       merging bool
+}
+

 // State returns the saved form of the view.
 // State returns the saved form of the view.

-func (v *View) State() viewState {
-       state := viewState{
+func (v *View) State() ViewState {
+       state := ViewState{

                Lines:   make([][2]int, len(v.lines)),
                Merging: v.merging,
        }
                Lines:   make([][2]int, len(v.lines)),
                Merging: v.merging,
        }


@@ -102,39 +99,17 @@ func (v *View) State() viewState {
 
 // Append adds the leaf of the next message as a line and merges when the view
 // is too large. It tells if a merge changed the view.
 
 // Append adds the leaf of the next message as a line and merges when the view
 // is too large. It tells if a merge changed the view.

-func (v *View) Append(tree nodeReader) bool {
-       v.lines = append(v.lines, nodeKey{0, v.end})
-       v.end++
-
-       return v.fit(tree)
-}
-
-// fit merges the most due pairs while a batch runs, and tells if a merge
-// changed the view.
-func (v *View) fit(tree nodeReader) bool {
-       size := v.Size(tree)
-       if size > v.high {
-               v.merging = true
-       }
-
-       merged := false
-       for v.merging && size > v.low {
-               best := v.mostDue(tree)
-               if best < 0 {
-                       return merged
-               }
-
-               left, right := v.lines[best], v.lines[best+1]
-               parent := nodeKey{left.level + 1, left.index / 2}
-               size += lineSize(tree, parent) - lineSize(tree, left) - lineSize(tree, right)
-               v.lines[best] = parent
-               v.lines = append(v.lines[:best+1], v.lines[best+2:]...)
-               merged = true
+func (v *View) Append(tree ViewNodeReader) (bool, error) {
+       line := NodeKey{0, v.end}
+       _, err := v.load(tree, line)
+       if err != nil {
+               return false, err

        }
 
        }
 

-       v.merging = false
+       v.lines = append(v.lines, line)
+       v.end++

 
 

-       return merged
+       return v.fit(tree)

 }
 
 // Coarsen takes each merge of other, a view of the same messages, and then
 }
 
 // Coarsen takes each merge of other, a view of the same messages, and then


@@ -142,16 +117,23 @@ func (v *View) fit(tree nodeReader) bool {
 // the coarser of the two lines that start at its first message. Dyadic ranges
 // either nest or do not overlap, so the result covers the messages without a
 // gap.
 // the coarser of the two lines that start at its first message. Dyadic ranges
 // either nest or do not overlap, so the result covers the messages without a
 // gap.

-func (v *View) Coarsen(other *View, tree nodeReader) {
-       lines := make([]nodeKey, 0, len(v.lines))
+func (v *View) Coarsen(other *View, tree ViewNodeReader) error {
+       lines := make([]NodeKey, 0, len(v.lines))
+       nodes := make(map[NodeKey]Node, len(v.nodes))

        mine, theirs := 0, 0
        for start := 0; start < v.end; {
                line := v.lines[mine]
        mine, theirs := 0, 0
        for start := 0; start < v.end; {
                line := v.lines[mine]

+               node, built := v.nodes[line]

                if other.lines[theirs].level > line.level {
                        line = other.lines[theirs]
                if other.lines[theirs].level > line.level {
                        line = other.lines[theirs]

+                       node, built = other.nodes[line]

                }
 
                lines = append(lines, line)
                }
 
                lines = append(lines, line)

+               if built {
+                       nodes[line] = node
+               }
+

                start = nodeEnd(line.level, line.index)
                for mine < len(v.lines) && v.lines[mine].index<<v.lines[mine].level < start {
                        mine++
                start = nodeEnd(line.level, line.index)
                for mine < len(v.lines) && v.lines[mine].index<<v.lines[mine].level < start {
                        mine++


@@ -163,74 +145,82 @@ func (v *View) Coarsen(other *View, tree nodeReader) {
        }
 
        v.lines = lines
        }
 
        v.lines = lines

+       v.nodes = nodes

        v.merging = true
        v.merging = true

-       v.fit(tree)
-}
+       _, err := v.fit(tree)

 
 

-// 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 nodeReader) int {
-       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
-               }
+       return err
+}

 
 

-               _, built := tree.Node(left.level+1, left.index/2)
-               if !built {
-                       continue
+// Refresh keeps node when it is the node of a pending line.
+func (v *View) Refresh(node Node) {
+       key := NodeKey{node.Level, node.Index}
+       for n := len(v.lines) - 1; n >= 0; n-- {
+               line := v.lines[n]
+               if line == key {
+                       v.nodes[key] = node
+                       return

                }
 
                }
 

-               last := nodeEnd(right.level, right.index) - 1
-               due := math.Ldexp(float64(v.end-last), -left.level)
-               if best < 0 || due > bestDue {
-                       best = n
-                       bestDue = due
+               if line.index<<line.level <= key.index<<key.level {
+                       return

                }
        }
                }
        }

-
-       return best

 }
 
 }
 

-// Size returns the sum of the line sizes.
-func (v *View) Size(tree nodeReader) int {
-       size := 0
+// Pending tells if a line of the view is not built yet.
+func (v *View) Pending() bool {

        for _, line := range v.lines {
        for _, line := range v.lines {

-               size += lineSize(tree, line)
+               _, built := v.nodes[line]
+               if !built {
+                       return true
+               }

        }
 
        }
 

-       return size
+       return false

 }
 
 // Render returns the view as the model reads it: one line "id+n|text" for each
 // node inside <chat> tags, with the newlines of the text as spaces.
 }
 
 // Render returns the view as the model reads it: one line "id+n|text" for each
 // node inside <chat> tags, with the newlines of the text as spaces.

-func (v *View) Render(tree nodeReader) string {
-       var text strings.Builder
-       text.WriteString("<chat>\n")
+func (v *View) Render() string {
+       return "<chat>\n" + strings.Join(v.LinesWithout(nil), "") + "</chat>"
+}
+
+// LinesWithout returns the lines of the view as the model reads them, each with
+// its newline, without the leaf lines of the messages in skip. A line that
+// merges such a message with others stays.
+func (v *View) LinesWithout(skip map[int]bool) []string {
+       lines := make([]string, 0, len(v.lines))

        for _, line := range v.lines {
        for _, line := range v.lines {

-               renderLine(&text, tree, line)
-       }
+               if line.level == 0 && skip[line.index] {
+                       continue
+               }

 
 

-       text.WriteString("</chat>")
+               var text strings.Builder

 
 

-       return text.String()
+               v.renderLine(&text, line)
+
+               lines = append(lines, text.String())
+       }
+
+       return lines

 }
 
 // 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.
 }
 
 // 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.

-func (v *View) Context(tree nodeReader, end int) string {
+func (v *View) Context(end int) string {

        var text strings.Builder
        var text strings.Builder

+

        text.WriteString("<chat>\n")
        text.WriteString("<chat>\n")

+

        for _, line := range v.lines {
        for _, line := range v.lines {

-               _, built := tree.Node(line.level, line.index)
+               _, built := v.nodes[line]

                if !built || nodeEnd(line.level, line.index) > end {
                        break
                }
 
                if !built || nodeEnd(line.level, line.index) > end {
                        break
                }
 

-               renderLine(&text, tree, line)
+               v.renderLine(&text, line)

        }
 
        text.WriteString("</chat>")
        }
 
        text.WriteString("</chat>")


@@ -238,20 +228,58 @@ func (v *View) Context(tree nodeReader, end int) string {
        return text.String()
 }
 
        return text.String()
 }
 

-// lineSize returns the size of a view line.
-func lineSize(tree nodeReader, line nodeKey) int {
-       node, built := tree.Node(line.level, line.index)
-       if !built {
-               return len(pending)
+// 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

        }
 
        }
 

-       return node.Size
+       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.
 }
 
 // renderLine writes one view line, "id+n|text", and a newline.

-func renderLine(text *strings.Builder, tree nodeReader, line nodeKey) {
-       body := pending
-       node, built := tree.Node(line.level, line.index)
+func (v *View) renderLine(text *strings.Builder, line NodeKey) {
+       body := viewPending
+       node, built := v.nodes[line]

        if built {
                body = strings.ReplaceAll(node.Text, "\n", " ")
        }
        if built {
                body = strings.ReplaceAll(node.Text, "\n", " ")
        }


@@ -263,3 +291,66 @@ func renderLine(text *strings.Builder, tree nodeReader, line nodeKey) {
        text.WriteString(body)
        text.WriteByte('\n')
 }
        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
+               }
+
+               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
+}
+
+// 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)
+}