1 files changed, 162 insertions, 0 deletions
diff --git a/workhorse/internal/lsif_transformer/parser/hovers.go b/workhorse/internal/lsif_transformer/parser/hovers.go
new file mode 100644
index 00000000000..e96d7e4fca3
--- /dev/null
+++ b/workhorse/internal/lsif_transformer/parser/hovers.go
@@ -0,0 +1,162 @@
+package parser
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+)
+
+type Offset struct {
+	At  int32
+	Len int32
+}
+
+type Hovers struct {
+	File          *os.File
+	Offsets       *cache
+	CurrentOffset int
+}
+
+type RawResult struct {
+	Contents []json.RawMessage `json:"contents"`
+}
+
+type RawData struct {
+	Id     Id        `json:"id"`
+	Result RawResult `json:"result"`
+}
+
+type HoverRef struct {
+	ResultSetId Id `json:"outV"`
+	HoverId     Id `json:"inV"`
+}
+
+type ResultSetRef struct {
+	ResultSetId Id `json:"outV"`
+	RefId       Id `json:"inV"`
+}
+
+func NewHovers(config Config) (*Hovers, error) {
+	tempPath := config.TempPath
+
+	file, err := ioutil.TempFile(tempPath, "hovers")
+	if err != nil {
+		return nil, err
+	}
+
+	if err := os.Remove(file.Name()); err != nil {
+		return nil, err
+	}
+
+	offsets, err := newCache(tempPath, "hovers-indexes", Offset{})
+	if err != nil {
+		return nil, err
+	}
+
+	return &Hovers{
+		File:          file,
+		Offsets:       offsets,
+		CurrentOffset: 0,
+	}, nil
+}
+
+func (h *Hovers) Read(label string, line []byte) error {
+	switch label {
+	case "hoverResult":
+		if err := h.addData(line); err != nil {
+			return err
+		}
+	case "textDocument/hover":
+		if err := h.addHoverRef(line); err != nil {
+			return err
+		}
+	case "textDocument/references":
+		if err := h.addResultSetRef(line); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (h *Hovers) For(refId Id) json.RawMessage {
+	var offset Offset
+	if err := h.Offsets.Entry(refId, &offset); err != nil || offset.Len == 0 {
+		return nil
+	}
+
+	hover := make([]byte, offset.Len)
+	_, err := h.File.ReadAt(hover, int64(offset.At))
+	if err != nil {
+		return nil
+	}
+
+	return json.RawMessage(hover)
+}
+
+func (h *Hovers) Close() error {
+	return combineErrors(
+		h.File.Close(),
+		h.Offsets.Close(),
+	)
+}
+
+func (h *Hovers) addData(line []byte) error {
+	var rawData RawData
+	if err := json.Unmarshal(line, &rawData); err != nil {
+		return err
+	}
+
+	codeHovers := []*codeHover{}
+	for _, rawContent := range rawData.Result.Contents {
+		c, err := newCodeHover(rawContent)
+		if err != nil {
+			return err
+		}
+
+		codeHovers = append(codeHovers, c)
+	}
+
+	codeHoversData, err := json.Marshal(codeHovers)
+	if err != nil {
+		return err
+	}
+
+	n, err := h.File.Write(codeHoversData)
+	if err != nil {
+		return err
+	}
+
+	offset := Offset{At: int32(h.CurrentOffset), Len: int32(n)}
+	h.CurrentOffset += n
+
+	return h.Offsets.SetEntry(rawData.Id, &offset)
+}
+
+func (h *Hovers) addHoverRef(line []byte) error {
+	var hoverRef HoverRef
+	if err := json.Unmarshal(line, &hoverRef); err != nil {
+		return err
+	}
+
+	var offset Offset
+	if err := h.Offsets.Entry(hoverRef.HoverId, &offset); err != nil {
+		return err
+	}
+
+	return h.Offsets.SetEntry(hoverRef.ResultSetId, &offset)
+}
+
+func (h *Hovers) addResultSetRef(line []byte) error {
+	var ref ResultSetRef
+	if err := json.Unmarshal(line, &ref); err != nil {
+		return err
+	}
+
+	var offset Offset
+	if err := h.Offsets.Entry(ref.ResultSetId, &offset); err != nil {
+		return nil
+	}
+
+	return h.Offsets.SetEntry(ref.RefId, &offset)
+}