internal/filetypes: generate FromFile

This adds the generated code and data file to emulate
the `filetypes.FromFile` function without using the
CUE evaluator.

For now, we keep the old implementation around to
check for consistency between old and new.
We'll remove the old implementation from the filetypes
package in a subsequent CL.

For #3280.

Signed-off-by: Roger Peppe <[email protected]>
Change-Id: I82d6f66854381bf9eb802646384a56a1fa6e4057
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1214209
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

Author: rogpeppe

internal/filetypes/filetypes.go

@@ -23,6 +23,7 @@ import (
 	"cuelang.org/go/cue/build"
 	"cuelang.org/go/cue/errors"
 	"cuelang.org/go/cue/token"
+	"cuelang.org/go/internal/filetypes/internal"
 )
 
 // Mode indicate the base mode of operation and indicates a different set of
@@ -50,26 +51,7 @@ func (m Mode) String() string {
 	}
 }
 
-// FileInfo defines the parsing plan for a file.
-type FileInfo struct {
-	Filename       string               `json:"filename"`
-	Encoding       build.Encoding       `json:"encoding,omitempty"`
-	Interpretation build.Interpretation `json:"interpretation,omitempty"`
-	Form           build.Form           `json:"form,omitempty"`
-
-	Definitions  bool `json:"definitions"`  // include/allow definition fields
-	Data         bool `json:"data"`         // include/allow regular fields
-	Optional     bool `json:"optional"`     // include/allow definition fields
-	Constraints  bool `json:"constraints"`  // include/allow constraints
-	References   bool `json:"references"`   // don't resolve/allow references
-	Cycles       bool `json:"cycles"`       // cycles are permitted
-	KeepDefaults bool `json:"keepDefaults"` // select/allow default values
-	Incomplete   bool `json:"incomplete"`   // permit incomplete values
-	Imports      bool `json:"imports"`      // don't expand/allow imports
-	Stream       bool `json:"stream"`       // permit streaming
-	Docs         bool `json:"docs"`         // show/allow docs
-	Attributes   bool `json:"attributes"`   // include/allow attributes
-}
+type FileInfo = internal.FileInfo
 
 // ParseArgs converts a sequence of command line arguments representing
 // files into a sequence of build file specifications.