| // Copyright 2018 The CUE Authors |
| // |
| // 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 cmd |
| |
| import ( |
| "errors" |
| "fmt" |
| "io/ioutil" |
| "os" |
| |
| "github.com/spf13/cobra" |
| |
| "cuelang.org/go/cue/format" |
| "cuelang.org/go/cue/load" |
| "cuelang.org/go/internal/diff" |
| "cuelang.org/go/tools/trim" |
| ) |
| |
| // TODO: |
| // - remove the limitations mentioned in the documentation |
| // - implement verification post-processing as extra safety |
| |
| // newTrimCmd creates a trim command |
| func newTrimCmd(c *Command) *cobra.Command { |
| cmd := &cobra.Command{ |
| Use: "trim", |
| Short: "remove superfluous fields", |
| Long: `trim removes fields from structs that can be inferred from constraints |
| |
| A field, struct, or list is removed if it is implied by a constraint, such |
| as from an optional field matching a required field, a list type value, |
| a comprehension or any other implied content. It will modify the files in place. |
| |
| |
| Limitations |
| |
| Removal is on a best effort basis. Some caveats: |
| - Fields in implied content may refer to fields within the struct in which |
| they are included, but are only resolved on a best-effort basis. |
| - Disjunctions that contain structs in implied content cannot be used to |
| remove fields. |
| - There is currently no verification step: manual verification is required. |
| |
| Examples: |
| |
| $ cat <<EOF > foo.cue |
| light: [string]: { |
| room: string |
| brightnessOff: *0.0 | >=0 & <=100.0 |
| brightnessOn: *100.0 | >=0 & <=100.0 |
| } |
| |
| light: ceiling50: { |
| room: "MasterBedroom" |
| brightnessOff: 0.0 // this line |
| brightnessOn: 100.0 // and this line will be removed |
| } |
| EOF |
| |
| $ cue trim foo.cue |
| $ cat foo.cue |
| light: [string]: { |
| room: string |
| brightnessOff: *0.0 | >=0 & <=100.0 |
| brightnessOn: *100.0 | >=0 & <=100.0 |
| } |
| |
| light: ceiling50: { |
| room: "MasterBedroom" |
| } |
| |
| It is guaranteed that the resulting files give the same output as before the |
| removal. |
| `, |
| RunE: mkRunE(c, runTrim), |
| } |
| |
| addOutFlags(cmd.Flags(), false) |
| |
| return cmd |
| } |
| |
| func runTrim(cmd *Command, args []string) error { |
| binst := loadFromArgs(cmd, args, nil) |
| if binst == nil { |
| return nil |
| } |
| instances := buildInstances(cmd, binst) |
| |
| dst := flagOutFile.String(cmd) |
| if dst != "" && dst != "-" && !flagForce.Bool(cmd) { |
| switch _, err := os.Stat(dst); { |
| case os.IsNotExist(err): |
| default: |
| return fmt.Errorf("error writing %q: file already exists", dst) |
| } |
| } |
| |
| overlay := map[string]load.Source{} |
| |
| for i, inst := range binst { |
| root := instances[i] |
| err := trim.Files(inst.Files, root, &trim.Config{ |
| Trace: flagTrace.Bool(cmd), |
| }) |
| if err != nil { |
| return err |
| } |
| |
| for _, f := range inst.Files { |
| overlay[f.Filename] = load.FromFile(f) |
| } |
| |
| } |
| |
| cfg := *defaultConfig.loadCfg |
| cfg.Overlay = overlay |
| tinsts := buildInstances(cmd, load.Instances(args, &cfg)) |
| if len(tinsts) != len(binst) { |
| return errors.New("unexpected number of new instances") |
| } |
| if !flagIgnore.Bool(cmd) { |
| for i, p := range instances { |
| k, script := diff.Final.Diff(p.Value(), tinsts[i].Value()) |
| if k != diff.Identity { |
| diff.Print(os.Stdout, script) |
| fmt.Println("Aborting trim, output differs after trimming. This is a bug! Use -i to force trim.") |
| fmt.Println("You can file a bug here: https://github.com/cuelang/cue/issues/new?assignees=&labels=NeedsInvestigation&template=bug_report.md&title=") |
| os.Exit(1) |
| } |
| } |
| } |
| |
| if flagDryrun.Bool(cmd) { |
| return nil |
| } |
| |
| for _, inst := range binst { |
| for _, f := range inst.Files { |
| filename := f.Filename |
| |
| opts := []format.Option{} |
| if flagSimplify.Bool(cmd) { |
| opts = append(opts, format.Simplify()) |
| } |
| |
| b, err := format.Node(f, opts...) |
| if err != nil { |
| return fmt.Errorf("error formatting file: %v", err) |
| } |
| |
| if dst == "-" { |
| _, err := cmd.OutOrStdout().Write(b) |
| if err != nil { |
| return err |
| } |
| continue |
| } else if dst != "" { |
| filename = dst |
| } |
| |
| err = ioutil.WriteFile(filename, b, 0644) |
| if err != nil { |
| return err |
| } |
| } |
| } |
| return nil |
| } |