readfile.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package driverutil
     6  
     7  // This file defines helpers for implementing [analysis.Pass.ReadFile].
     8  
     9  import (
    10  	"fmt"
    11  	"slices"
    12  
    13  	"golang.org/x/tools/go/analysis"
    14  )
    15  
    16  // A ReadFileFunc is a function that returns the
    17  // contents of a file, such as [os.ReadFile].
    18  type ReadFileFunc = func(filename string) ([]byte, error)
    19  
    20  // CheckedReadFile returns a wrapper around a Pass.ReadFile
    21  // function that performs the appropriate checks.
    22  func CheckedReadFile(pass *analysis.Pass, readFile ReadFileFunc) ReadFileFunc {
    23  	return func(filename string) ([]byte, error) {
    24  		if err := CheckReadable(pass, filename); err != nil {
    25  			return nil, err
    26  		}
    27  		return readFile(filename)
    28  	}
    29  }
    30  
    31  // CheckReadable enforces the access policy defined by the ReadFile field of [analysis.Pass].
    32  func CheckReadable(pass *analysis.Pass, filename string) error {
    33  	if slices.Contains(pass.OtherFiles, filename) ||
    34  		slices.Contains(pass.IgnoredFiles, filename) {
    35  		return nil
    36  	}
    37  	for _, f := range pass.Files {
    38  		if pass.Fset.File(f.FileStart).Name() == filename {
    39  			return nil
    40  		}
    41  	}
    42  	return fmt.Errorf("Pass.ReadFile: %s is not among OtherFiles, IgnoredFiles, or names of Files", filename)
    43  }
    44
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