internal/lsp: add find all references

This change implements the find all references feature by finding all of
the uses and definitions of the identifier within the current package.

Testing for references is done using "refs" in the testdata files and
marking the references in the package.

Change-Id: Ieb44b68608e940df5f65c3052eb9ec974f6fae6c
Reviewed-on: https://go-review.googlesource.com/c/tools/+/181122
Run-TryBot: Suzy Mueller <suzmue@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/internal/lsp/references.go b/internal/lsp/references.go
new file mode 100644
index 000000000..27862441e
--- /dev/null
+++ b/internal/lsp/references.go
@@ -0,0 +1,56 @@
+package lsp
+
+import (
+	"context"
+
+	"golang.org/x/tools/internal/lsp/protocol"
+	"golang.org/x/tools/internal/lsp/source"
+	"golang.org/x/tools/internal/span"
+)
+
+func (s *Server) references(ctx context.Context, params *protocol.ReferenceParams) ([]protocol.Location, error) {
+	uri := span.NewURI(params.TextDocument.URI)
+	view := s.session.ViewOf(uri)
+	f, m, err := getGoFile(ctx, view, uri)
+	if err != nil {
+		return nil, err
+	}
+	spn, err := m.PointSpan(params.Position)
+	if err != nil {
+		return nil, err
+	}
+	rng, err := spn.Range(m.Converter)
+	if err != nil {
+		return nil, err
+	}
+
+	// Find all references to the identifier at the position.
+	ident, err := source.Identifier(ctx, view, f, rng.Start)
+	if err != nil {
+		return nil, err
+	}
+	references, err := ident.References(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get the location of each reference to return as the result.
+	locations := make([]protocol.Location, 0, len(references))
+	for _, ref := range references {
+		refSpan, err := ref.Range.Span()
+		if err != nil {
+			return nil, err
+		}
+		_, refM, err := getSourceFile(ctx, view, refSpan.URI())
+		if err != nil {
+			return nil, err
+		}
+		loc, err := refM.Location(refSpan)
+		if err != nil {
+			return nil, err
+		}
+
+		locations = append(locations, loc)
+	}
+	return locations, nil
+}