Complete context on forwarded local errors

[onechat] / view.go

diff --git a/view.go b/view.go
index a75b1d8418fc9857d6aafbf38a822c989a817d77..9af1c21476fccfb2d1aa7ba394d8a3120ef2c35b 100644 (file)
--- a/view.go
+++ b/view.go
@@ -9,25 +9,20 @@ 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 {
-       Built(level, index int) (bool, error)
-       Node(level, index int) (Node, bool, error)
-}
-

 // 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
 // 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


@@ -46,69 +41,36 @@ type nodeReader interface {
 type View struct {
        high    int
        low     int
 type View struct {
        high    int
        low     int

-       lines   []nodeKey
-       nodes   map[nodeKey]Node
+       lines   []NodeKey
+       nodes   map[NodeKey]Node

        end     int
        merging bool
 }
 
        end     int
        merging bool
 }
 

-// viewState is the saved form of a View. The limits are not part of it.
-type viewState struct {
+// 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"`
 }
 
        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,
 // 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 nodeReader) (*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)
+               nodes: make(map[NodeKey]Node),

        }
        }

-
-       return v, nil
-}
-
-// load keeps the node of line when it is built, and tells if it is.
-func (v *View) load(tree nodeReader, 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

 }
 
 // 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,
        }


@@ -122,22 +84,39 @@ 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, error) {
-       line := nodeKey{0, v.end}
+func (v *View) Append(tree ViewNodeReader) (bool, error) {
+       line := NodeKey{0, v.end}

        _, err := v.load(tree, line)
        if err != nil {
        _, err := v.load(tree, line)
        if err != nil {

-               return false, err
+               return false, fmt.Errorf("load appended leaf: %w", err)

        }
 
        v.lines = append(v.lines, line)
        v.end++
 
        }
 
        v.lines = append(v.lines, line)
        v.end++
 

-       return v.fit(tree)
+       merged, err := v.fit(tree)
+       if err != nil {
+               return merged, fmt.Errorf("fit appended view: %w", err)
+       }
+
+       return merged, nil
+}
+
+// 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.
 }
 
 // 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, error) {
+func (v *View) fit(tree ViewNodeReader) (bool, error) {

        size := v.Size()
        if size > v.high {
                v.merging = true
        size := v.Size()
        if size > v.high {
                v.merging = true


@@ -147,19 +126,24 @@ func (v *View) fit(tree nodeReader) (bool, error) {
        for v.merging && size > v.low {
                best, err := v.mostDue(tree)
                if err != nil || best < 0 {
        for v.merging && size > v.low {
                best, err := v.mostDue(tree)
                if err != nil || best < 0 {

-                       return merged, err
+                       if err != nil {
+                               return merged, fmt.Errorf("choose merge candidate: %w", err)
+                       }
+
+                       return merged, nil

                }
 
                left, right := v.lines[best], v.lines[best+1]
                }
 
                left, right := v.lines[best], v.lines[best+1]

-               parent := nodeKey{left.level + 1, left.index / 2}
+               parent := NodeKey{left.level + 1, left.index / 2}

                _, err = v.load(tree, parent)
                if err != nil {
                _, err = v.load(tree, parent)
                if err != nil {

-                       return merged, err
+                       return merged, fmt.Errorf("load merged parent: %w", err)

                }
 
                size += v.lineSize(parent) - v.lineSize(left) - v.lineSize(right)
                delete(v.nodes, left)
                delete(v.nodes, right)
                }
 
                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.lines[best] = parent
                v.lines = append(v.lines[:best+1], v.lines[best+2:]...)
                merged = true


@@ -170,14 +154,65 @@ func (v *View) fit(tree nodeReader) (bool, error) {
        return merged, nil
 }
 
        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
 // either nest or do not overlap, so the result covers the messages without a
 // gap.
 // 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
 // either nest or do not overlap, so the result covers the messages without a
 // gap.

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


@@ -210,40 +245,9 @@ func (v *View) Coarsen(other *View, tree nodeReader) error {
        return err
 }
 
        return err
 }
 

-// 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, 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, err
-               }
-
-               if built {
-                       best = n
-                       bestDue = due
-               }
-       }
-
-       return best, nil
-}
-

 // Refresh keeps node when it is the node of a pending line.
 func (v *View) Refresh(node Node) {
 // Refresh keeps node when it is the node of a pending line.
 func (v *View) Refresh(node Node) {

-       key := nodeKey{node.Level, node.Index}
+       key := NodeKey{node.Level, node.Index}

        for n := len(v.lines) - 1; n >= 0; n-- {
                line := v.lines[n]
                if line == key {
        for n := len(v.lines) - 1; n >= 0; n-- {
                line := v.lines[n]
                if line == key {


@@ -257,24 +261,16 @@ func (v *View) Refresh(node Node) {
        }
 }
 
        }
 }
 

-// Size returns the sum of the line sizes.
-func (v *View) Size() 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 += v.lineSize(line)
-       }
-
-       return size
-}
-
-// lineSize returns the size of a view line.
-func (v *View) lineSize(line nodeKey) int {
-       node, built := v.nodes[line]
-       if !built {
-               return len(pending)
+               _, built := v.nodes[line]
+               if !built {
+                       return true
+               }

        }
 
        }
 

-       return node.Size
+       return false

 }
 
 // Render returns the view as the model reads it: one line "id+n|text" for each
 }
 
 // Render returns the view as the model reads it: one line "id+n|text" for each


@@ -294,7 +290,9 @@ func (v *View) LinesWithout(skip map[int]bool) []string {
                }
 
                var text strings.Builder
                }
 
                var text strings.Builder

+

                v.renderLine(&text, line)
                v.renderLine(&text, line)

+

                lines = append(lines, text.String())
        }
 
                lines = append(lines, text.String())
        }
 


@@ -302,8 +300,8 @@ func (v *View) LinesWithout(skip map[int]bool) []string {
 }
 
 // renderLine writes one view line, "id+n|text", and a newline.
 }
 
 // renderLine writes one view line, "id+n|text", and a newline.

-func (v *View) renderLine(text *strings.Builder, line nodeKey) {
-       body := pending
+func (v *View) renderLine(text *strings.Builder, line NodeKey) {
+       body := viewPending

        node, built := v.nodes[line]
        if built {
                body = strings.ReplaceAll(node.Text, "\n", " ")
        node, built := v.nodes[line]
        if built {
                body = strings.ReplaceAll(node.Text, "\n", " ")


@@ -322,7 +320,9 @@ func (v *View) renderLine(text *strings.Builder, line nodeKey) {
 // sees a pending mark or a part of a message.
 func (v *View) Context(end int) string {
        var text strings.Builder
 // sees a pending mark or a part of a message.
 func (v *View) Context(end int) string {
        var text strings.Builder

+

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

+

        for _, line := range v.lines {
                _, built := v.nodes[line]
                if !built || nodeEnd(line.level, line.index) > end {
        for _, line := range v.lines {
                _, built := v.nodes[line]
                if !built || nodeEnd(line.level, line.index) > end {


@@ -336,3 +336,30 @@ func (v *View) Context(end int) string {
 
        return text.String()
 }
 
        return text.String()
 }

+
+// 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, fmt.Errorf("load restored view node: %w", 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
+}