cuelang.org/go@v0.10.1/mod/module/escape.go (about)

     1  package module
     2  
     3  import (
     4  	"fmt"
     5  	"strings"
     6  	"unicode/utf8"
     7  
     8  	"cuelang.org/go/internal/mod/semver"
     9  )
    10  
    11  // EscapePath returns the escaped form of the given module path
    12  // (without the major version suffix).
    13  // It fails if the module path is invalid.
    14  func EscapePath(path string) (escaped string, err error) {
    15  	if err := CheckPathWithoutVersion(path); err != nil {
    16  		return "", err
    17  	}
    18  	// Technically there's no need to escape capital letters because CheckPath
    19  	// doesn't allow them, but let's be defensive.
    20  	return escapeString(path)
    21  }
    22  
    23  // EscapeVersion returns the escaped form of the given module version.
    24  // Versions must be in (possibly non-canonical) semver form and must be valid file names
    25  // and not contain exclamation marks.
    26  func EscapeVersion(v string) (escaped string, err error) {
    27  	if !semver.IsValid(v) {
    28  		return "", &InvalidVersionError{
    29  			Version: v,
    30  			Err:     fmt.Errorf("version is not in semver syntax"),
    31  		}
    32  	}
    33  	if err := checkElem(v, filePath); err != nil || strings.Contains(v, "!") {
    34  		return "", &InvalidVersionError{
    35  			Version: v,
    36  			Err:     fmt.Errorf("disallowed version string"),
    37  		}
    38  	}
    39  	return escapeString(v)
    40  }
    41  
    42  func escapeString(s string) (escaped string, err error) {
    43  	haveUpper := false
    44  	for _, r := range s {
    45  		if r == '!' || r >= utf8.RuneSelf {
    46  			// This should be disallowed by CheckPath, but diagnose anyway.
    47  			// The correctness of the escaping loop below depends on it.
    48  			return "", fmt.Errorf("internal error: inconsistency in EscapePath")
    49  		}
    50  		if 'A' <= r && r <= 'Z' {
    51  			haveUpper = true
    52  		}
    53  	}
    54  
    55  	if !haveUpper {
    56  		return s, nil
    57  	}
    58  
    59  	var buf []byte
    60  	for _, r := range s {
    61  		if 'A' <= r && r <= 'Z' {
    62  			buf = append(buf, '!', byte(r+'a'-'A'))
    63  		} else {
    64  			buf = append(buf, byte(r))
    65  		}
    66  	}
    67  	return string(buf), nil
    68  }