1 files changed, 91 insertions, 0 deletions
diff --git a/go/tools/gopackagesdriver/driver_request.go b/go/tools/gopackagesdriver/driver_request.go
new file mode 100644
index 00000000..db572dcc
--- /dev/null
+++ b/go/tools/gopackagesdriver/driver_request.go
@@ -0,0 +1,91 @@
+// Copyright 2021 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+)
+
+// From https://pkg.go.dev/golang.org/x/tools/go/packages#LoadMode
+type LoadMode int
+
+// Only NeedExportsFile is needed in our case
+const (
+	// NeedName adds Name and PkgPath.
+	NeedName LoadMode = 1 << iota
+
+	// NeedFiles adds GoFiles and OtherFiles.
+	NeedFiles
+
+	// NeedCompiledGoFiles adds CompiledGoFiles.
+	NeedCompiledGoFiles
+
+	// NeedImports adds Imports. If NeedDeps is not set, the Imports field will contain
+	// "placeholder" Packages with only the ID set.
+	NeedImports
+
+	// NeedDeps adds the fields requested by the LoadMode in the packages in Imports.
+	NeedDeps
+
+	// NeedExportsFile adds ExportFile.
+	NeedExportFile
+
+	// NeedTypes adds Types, Fset, and IllTyped.
+	NeedTypes
+
+	// NeedSyntax adds Syntax.
+	NeedSyntax
+
+	// NeedTypesInfo adds TypesInfo.
+	NeedTypesInfo
+
+	// NeedTypesSizes adds TypesSizes.
+	NeedTypesSizes
+
+	// typecheckCgo enables full support for type checking cgo. Requires Go 1.15+.
+	// Modifies CompiledGoFiles and Types, and has no effect on its own.
+	typecheckCgo
+
+	// NeedModule adds Module.
+	NeedModule
+)
+
+// Deprecated: NeedExportsFile is a historical misspelling of NeedExportFile.
+const NeedExportsFile = NeedExportFile
+
+// From https://github.com/golang/tools/blob/v0.1.0/go/packages/external.go#L32
+// Most fields are disabled since there is no need for them
+type DriverRequest struct {
+	Mode LoadMode `json:"mode"`
+	// Env specifies the environment the underlying build system should be run in.
+	// Env []string `json:"env"`
+	// BuildFlags are flags that should be passed to the underlying build system.
+	// BuildFlags []string `json:"build_flags"`
+	// Tests specifies whether the patterns should also return test packages.
+	Tests bool `json:"tests"`
+	// Overlay maps file paths (relative to the driver's working directory) to the byte contents
+	// of overlay files.
+	// Overlay map[string][]byte `json:"overlay"`
+}
+
+func ReadDriverRequest(r io.Reader) (*DriverRequest, error) {
+	req := &DriverRequest{}
+	if err := json.NewDecoder(r).Decode(&req); err != nil {
+		return nil, fmt.Errorf("unable to decode driver request: %w", err)
+	}
+	return req, nil
+}