gen_known_imports.go

Documentation: github.com/bazelbuild/bazel-gazelle/language/proto/gen

     1  /* Copyright 2018 The Bazel Authors. All rights reserved.
     2  
     3  Licensed under the Apache License, Version 2.0 (the "License");
     4  you may not use this file except in compliance with the License.
     5  You may obtain a copy of the License at
     6  
     7     http://www.apache.org/licenses/LICENSE-2.0
     8  
     9  Unless required by applicable law or agreed to in writing, software
    10  distributed under the License is distributed on an "AS IS" BASIS,
    11  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  See the License for the specific language governing permissions and
    13  limitations under the License.
    14  */
    15  
    16  // gen_known_imports generates a .go file that with a map from either proto or
    17  // go import strings to Bazel label strings. The imports for all languages
    18  // are stored in a proto.csv file.
    19  
    20  package main
    21  
    22  import (
    23  	"bufio"
    24  	"bytes"
    25  	"encoding/csv"
    26  	"flag"
    27  	"fmt"
    28  	"go/format"
    29  	"log"
    30  	"os"
    31  	"path/filepath"
    32  	"text/template"
    33  
    34  	"github.com/bazelbuild/bazel-gazelle/label"
    35  )
    36  
    37  var progName = filepath.Base(os.Args[0])
    38  
    39  var knownImportsTpl = template.Must(template.New("known_imports.go").Parse(`
    40  // Generated by language/proto/gen/gen_known_imports.go
    41  // From {{.ProtoCsv}}
    42  
    43  package {{.Package}}
    44  
    45  import "github.com/bazelbuild/bazel-gazelle/label"
    46  
    47  var {{.Var}} = map[string]label.Label{
    48  {{range .Bindings}}
    49  	{{printf "%q: label.Label{Repo: %q, Pkg: %q, Name: %q}" .Import .Label.Repo .Label.Pkg .Label.Name}},
    50  {{- end}}
    51  }
    52  `))
    53  
    54  type data struct {
    55  	ProtoCsv, Package, Var string
    56  	Bindings               []binding
    57  }
    58  
    59  type binding struct {
    60  	Import string
    61  	Label  label.Label
    62  }
    63  
    64  func main() {
    65  	log.SetPrefix(progName + ": ")
    66  	log.SetFlags(0)
    67  	if err := run(os.Args[1:]); err != nil {
    68  		log.Fatal(err)
    69  	}
    70  }
    71  
    72  func run(args []string) (err error) {
    73  	fs := flag.NewFlagSet(progName, flag.ExitOnError)
    74  	var protoCsvPath, knownImportsPath, package_, var_ string
    75  	var keyColumn, valueColumn int
    76  	fs.StringVar(&protoCsvPath, "proto_csv", "", "path to proto.csv input file")
    77  	fs.StringVar(&knownImportsPath, "known_imports", "", "path to known_imports.go output file")
    78  	fs.StringVar(&package_, "package", "", "package name in generated file")
    79  	fs.StringVar(&var_, "var", "", "var name in generated file")
    80  	fs.IntVar(&keyColumn, "key", 0, "key column number")
    81  	fs.IntVar(&valueColumn, "value", 1, "value column number")
    82  	if err = fs.Parse(args); err != nil {
    83  		return fmt.Errorf("invalid flag: %v", err)
    84  	}
    85  	if protoCsvPath == "" {
    86  		return fmt.Errorf("-proto_csv not set")
    87  	}
    88  	if knownImportsPath == "" {
    89  		return fmt.Errorf("-known_imports not set")
    90  	}
    91  	if package_ == "" {
    92  		return fmt.Errorf("-package not set")
    93  	}
    94  	if var_ == "" {
    95  		return fmt.Errorf("-var not set")
    96  	}
    97  
    98  	protoCsvFile, err := os.Open(protoCsvPath)
    99  	if err != nil {
   100  		return err
   101  	}
   102  	r := csv.NewReader(bufio.NewReader(protoCsvFile))
   103  	r.Comment = '#'
   104  	r.FieldsPerRecord = 4
   105  	records, err := r.ReadAll()
   106  	protoCsvFile.Close()
   107  	if err != nil {
   108  		return err
   109  	}
   110  	data := data{
   111  		ProtoCsv: protoCsvPath,
   112  		Package:  package_,
   113  		Var:      var_,
   114  	}
   115  	seen := make(map[string]label.Label)
   116  	for _, rec := range records {
   117  		imp := rec[keyColumn]
   118  		lbl, err := label.Parse(rec[valueColumn])
   119  		if err != nil {
   120  			return err
   121  		}
   122  		if seenLabel, ok := seen[imp]; ok {
   123  			if !seenLabel.Equal(lbl) {
   124  				return fmt.Errorf("for key %s, multiple values (%s and %s)", imp, seenLabel, lbl)
   125  			}
   126  			continue
   127  		}
   128  		seen[imp] = lbl
   129  		data.Bindings = append(data.Bindings, binding{imp, lbl})
   130  	}
   131  
   132  	knownImportsBuf := &bytes.Buffer{}
   133  	if err := knownImportsTpl.Execute(knownImportsBuf, data); err != nil {
   134  		return err
   135  	}
   136  	knownImportsData, err := format.Source(knownImportsBuf.Bytes())
   137  	if err != nil {
   138  		return err
   139  	}
   140  	if err := os.WriteFile(knownImportsPath, knownImportsData, 0o666); err != nil {
   141  		return err
   142  	}
   143  
   144  	return nil
   145  }
   146
View as plain text