1 files changed, 109 insertions, 0 deletions
diff --git a/workhorse/internal/lsif_transformer/parser/parser.go b/workhorse/internal/lsif_transformer/parser/parser.go
new file mode 100644
index 00000000000..085e7a856aa
--- /dev/null
+++ b/workhorse/internal/lsif_transformer/parser/parser.go
@@ -0,0 +1,109 @@
+package parser
+
+import (
+	"archive/zip"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"gitlab.com/gitlab-org/labkit/log"
+)
+
+var (
+	Lsif = "lsif"
+)
+
+type Parser struct {
+	Docs *Docs
+
+	pr *io.PipeReader
+}
+
+type Config struct {
+	TempPath string
+}
+
+func NewParser(ctx context.Context, r io.Reader, config Config) (io.ReadCloser, error) {
+	docs, err := NewDocs(config)
+	if err != nil {
+		return nil, err
+	}
+
+	// ZIP files need to be seekable. Don't hold it all in RAM, use a tempfile
+	tempFile, err := ioutil.TempFile(config.TempPath, Lsif)
+	if err != nil {
+		return nil, err
+	}
+
+	defer tempFile.Close()
+
+	if err := os.Remove(tempFile.Name()); err != nil {
+		return nil, err
+	}
+
+	size, err := io.Copy(tempFile, r)
+	if err != nil {
+		return nil, err
+	}
+	log.WithContextFields(ctx, log.Fields{"lsif_zip_cache_bytes": size}).Print("cached incoming LSIF zip on disk")
+
+	zr, err := zip.NewReader(tempFile, size)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(zr.File) == 0 {
+		return nil, errors.New("empty zip file")
+	}
+
+	file, err := zr.File[0].Open()
+	if err != nil {
+		return nil, err
+	}
+
+	defer file.Close()
+
+	if err := docs.Parse(file); err != nil {
+		return nil, err
+	}
+
+	pr, pw := io.Pipe()
+	parser := &Parser{
+		Docs: docs,
+		pr:   pr,
+	}
+
+	go parser.transform(pw)
+
+	return parser, nil
+}
+
+func (p *Parser) Read(b []byte) (int, error) {
+	return p.pr.Read(b)
+}
+
+func (p *Parser) Close() error {
+	p.pr.Close()
+
+	return p.Docs.Close()
+}
+
+func (p *Parser) transform(pw *io.PipeWriter) {
+	zw := zip.NewWriter(pw)
+
+	if err := p.Docs.SerializeEntries(zw); err != nil {
+		zw.Close() // Free underlying resources only
+		pw.CloseWithError(fmt.Errorf("lsif parser: Docs.SerializeEntries: %v", err))
+		return
+	}
+
+	if err := zw.Close(); err != nil {
+		pw.CloseWithError(fmt.Errorf("lsif parser: ZipWriter.Close: %v", err))
+		return
+	}
+
+	pw.Close()
+}