format.go

     1  // Copyright 2024 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  // This file implements (error and trace) message formatting support.
     6  
     7  package types
     8  
     9  import (
    10  	"bytes"
    11  	"fmt"
    12  	"go/ast"
    13  	"go/token"
    14  	"strconv"
    15  	"strings"
    16  )
    17  
    18  func sprintf(fset *token.FileSet, qf Qualifier, tpSubscripts bool, format string, args ...any) string {
    19  	for i, arg := range args {
    20  		switch a := arg.(type) {
    21  		case nil:
    22  			arg = "<nil>"
    23  		case operand:
    24  			panic("got operand instead of *operand")
    25  		case *operand:
    26  			arg = operandString(a, qf)
    27  		case token.Pos:
    28  			if fset != nil {
    29  				arg = fset.Position(a).String()
    30  			}
    31  		case ast.Expr:
    32  			arg = ExprString(a)
    33  		case []ast.Expr:
    34  			var buf bytes.Buffer
    35  			buf.WriteByte('[')
    36  			writeExprList(&buf, a)
    37  			buf.WriteByte(']')
    38  			arg = buf.String()
    39  		case Object:
    40  			arg = ObjectString(a, qf)
    41  		case Type:
    42  			var buf bytes.Buffer
    43  			w := newTypeWriter(&buf, qf)
    44  			w.tpSubscripts = tpSubscripts
    45  			w.typ(a)
    46  			arg = buf.String()
    47  		case []Type:
    48  			var buf bytes.Buffer
    49  			w := newTypeWriter(&buf, qf)
    50  			w.tpSubscripts = tpSubscripts
    51  			buf.WriteByte('[')
    52  			for i, x := range a {
    53  				if i > 0 {
    54  					buf.WriteString(", ")
    55  				}
    56  				w.typ(x)
    57  			}
    58  			buf.WriteByte(']')
    59  			arg = buf.String()
    60  		case []*TypeParam:
    61  			var buf bytes.Buffer
    62  			w := newTypeWriter(&buf, qf)
    63  			w.tpSubscripts = tpSubscripts
    64  			buf.WriteByte('[')
    65  			for i, x := range a {
    66  				if i > 0 {
    67  					buf.WriteString(", ")
    68  				}
    69  				w.typ(x)
    70  			}
    71  			buf.WriteByte(']')
    72  			arg = buf.String()
    73  		}
    74  		args[i] = arg
    75  	}
    76  	return fmt.Sprintf(format, args...)
    77  }
    78  
    79  // check may be nil.
    80  func (check *Checker) sprintf(format string, args ...any) string {
    81  	var fset *token.FileSet
    82  	var qf Qualifier
    83  	if check != nil {
    84  		fset = check.fset
    85  		qf = check.qualifier
    86  	}
    87  	return sprintf(fset, qf, false, format, args...)
    88  }
    89  
    90  func (check *Checker) trace(pos token.Pos, format string, args ...any) {
    91  	pos1 := check.fset.Position(pos)
    92  	// Use the width of line and pos values to align the ":" by adding padding before it.
    93  	// Cap padding at 5: 3 digits for the line, 2 digits for the column number, which is
    94  	// ok for most cases.
    95  	w := ndigits(pos1.Line) + ndigits(pos1.Column)
    96  	pad := "     "[:max(5-w, 0)]
    97  	fmt.Printf("%s%s:  %s%s\n",
    98  		pos1,
    99  		pad,
   100  		strings.Repeat(".  ", check.indent),
   101  		sprintf(check.fset, check.qualifier, true, format, args...),
   102  	)
   103  }
   104  
   105  // ndigits returns the number of decimal digits in x.
   106  // For x < 10, the result is always 1.
   107  // For x > 100, the result is always 3.
   108  func ndigits(x int) int {
   109  	switch {
   110  	case x < 10:
   111  		return 1
   112  	case x < 100:
   113  		return 2
   114  	default:
   115  		return 3
   116  	}
   117  }
   118  
   119  // dump is only needed for debugging
   120  func (check *Checker) dump(format string, args ...any) {
   121  	fmt.Println(sprintf(check.fset, check.qualifier, true, format, args...))
   122  }
   123  
   124  func (check *Checker) qualifier(pkg *Package) string {
   125  	// Qualify the package unless it's the package being type-checked.
   126  	if pkg != check.pkg {
   127  		if check.pkgPathMap == nil {
   128  			check.pkgPathMap = make(map[string]map[string]bool)
   129  			check.seenPkgMap = make(map[*Package]bool)
   130  			check.markImports(check.pkg)
   131  		}
   132  		// If the same package name was used by multiple packages, display the full path.
   133  		if len(check.pkgPathMap[pkg.name]) > 1 {
   134  			return strconv.Quote(pkg.path)
   135  		}
   136  		return pkg.name
   137  	}
   138  	return ""
   139  }
   140  
   141  // markImports recursively walks pkg and its imports, to record unique import
   142  // paths in pkgPathMap.
   143  func (check *Checker) markImports(pkg *Package) {
   144  	if check.seenPkgMap[pkg] {
   145  		return
   146  	}
   147  	check.seenPkgMap[pkg] = true
   148  
   149  	forName, ok := check.pkgPathMap[pkg.name]
   150  	if !ok {
   151  		forName = make(map[string]bool)
   152  		check.pkgPathMap[pkg.name] = forName
   153  	}
   154  	forName[pkg.path] = true
   155  
   156  	for _, imp := range pkg.imports {
   157  		check.markImports(imp)
   158  	}
   159  }
   160  
   161  // stripAnnotations removes internal (type) annotations from s.
   162  func stripAnnotations(s string) string {
   163  	var buf strings.Builder
   164  	for _, r := range s {
   165  		// strip #'s and subscript digits
   166  		if r < '₀' || '₀'+10 <= r { // '₀' == U+2080
   167  			buf.WriteRune(r)
   168  		}
   169  	}
   170  	if buf.Len() < len(s) {
   171  		return buf.String()
   172  	}
   173  	return s
   174  }
   175
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