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Source file src/go/token/position_test.go

Documentation: go/token

     1  // Copyright 2010 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 token
     6  
     7  import (
     8  	"fmt"
     9  	"math/rand"
    10  	"sync"
    11  	"testing"
    12  )
    13  
    14  func checkPos(t *testing.T, msg string, got, want Position) {
    15  	if got.Filename != want.Filename {
    16  		t.Errorf("%s: got filename = %q; want %q", msg, got.Filename, want.Filename)
    17  	}
    18  	if got.Offset != want.Offset {
    19  		t.Errorf("%s: got offset = %d; want %d", msg, got.Offset, want.Offset)
    20  	}
    21  	if got.Line != want.Line {
    22  		t.Errorf("%s: got line = %d; want %d", msg, got.Line, want.Line)
    23  	}
    24  	if got.Column != want.Column {
    25  		t.Errorf("%s: got column = %d; want %d", msg, got.Column, want.Column)
    26  	}
    27  }
    28  
    29  func TestNoPos(t *testing.T) {
    30  	if NoPos.IsValid() {
    31  		t.Errorf("NoPos should not be valid")
    32  	}
    33  	var fset *FileSet
    34  	checkPos(t, "nil NoPos", fset.Position(NoPos), Position{})
    35  	fset = NewFileSet()
    36  	checkPos(t, "fset NoPos", fset.Position(NoPos), Position{})
    37  }
    38  
    39  var tests = []struct {
    40  	filename string
    41  	source   []byte // may be nil
    42  	size     int
    43  	lines    []int
    44  }{
    45  	{"a", []byte{}, 0, []int{}},
    46  	{"b", []byte("01234"), 5, []int{0}},
    47  	{"c", []byte("\n\n\n\n\n\n\n\n\n"), 9, []int{0, 1, 2, 3, 4, 5, 6, 7, 8}},
    48  	{"d", nil, 100, []int{0, 5, 10, 20, 30, 70, 71, 72, 80, 85, 90, 99}},
    49  	{"e", nil, 777, []int{0, 80, 100, 120, 130, 180, 267, 455, 500, 567, 620}},
    50  	{"f", []byte("package p\n\nimport \"fmt\""), 23, []int{0, 10, 11}},
    51  	{"g", []byte("package p\n\nimport \"fmt\"\n"), 24, []int{0, 10, 11}},
    52  	{"h", []byte("package p\n\nimport \"fmt\"\n "), 25, []int{0, 10, 11, 24}},
    53  }
    54  
    55  func linecol(lines []int, offs int) (int, int) {
    56  	prevLineOffs := 0
    57  	for line, lineOffs := range lines {
    58  		if offs < lineOffs {
    59  			return line, offs - prevLineOffs + 1
    60  		}
    61  		prevLineOffs = lineOffs
    62  	}
    63  	return len(lines), offs - prevLineOffs + 1
    64  }
    65  
    66  func verifyPositions(t *testing.T, fset *FileSet, f *File, lines []int) {
    67  	for offs := 0; offs < f.Size(); offs++ {
    68  		p := f.Pos(offs)
    69  		offs2 := f.Offset(p)
    70  		if offs2 != offs {
    71  			t.Errorf("%s, Offset: got offset %d; want %d", f.Name(), offs2, offs)
    72  		}
    73  		line, col := linecol(lines, offs)
    74  		msg := fmt.Sprintf("%s (offs = %d, p = %d)", f.Name(), offs, p)
    75  		checkPos(t, msg, f.Position(f.Pos(offs)), Position{f.Name(), offs, line, col})
    76  		checkPos(t, msg, fset.Position(p), Position{f.Name(), offs, line, col})
    77  	}
    78  }
    79  
    80  func makeTestSource(size int, lines []int) []byte {
    81  	src := make([]byte, size)
    82  	for _, offs := range lines {
    83  		if offs > 0 {
    84  			src[offs-1] = '\n'
    85  		}
    86  	}
    87  	return src
    88  }
    89  
    90  func TestPositions(t *testing.T) {
    91  	const delta = 7 // a non-zero base offset increment
    92  	fset := NewFileSet()
    93  	for _, test := range tests {
    94  		// verify consistency of test case
    95  		if test.source != nil && len(test.source) != test.size {
    96  			t.Errorf("%s: inconsistent test case: got file size %d; want %d", test.filename, len(test.source), test.size)
    97  		}
    98  
    99  		// add file and verify name and size
   100  		f := fset.AddFile(test.filename, fset.Base()+delta, test.size)
   101  		if f.Name() != test.filename {
   102  			t.Errorf("got filename %q; want %q", f.Name(), test.filename)
   103  		}
   104  		if f.Size() != test.size {
   105  			t.Errorf("%s: got file size %d; want %d", f.Name(), f.Size(), test.size)
   106  		}
   107  		if fset.File(f.Pos(0)) != f {
   108  			t.Errorf("%s: f.Pos(0) was not found in f", f.Name())
   109  		}
   110  
   111  		// add lines individually and verify all positions
   112  		for i, offset := range test.lines {
   113  			f.AddLine(offset)
   114  			if f.LineCount() != i+1 {
   115  				t.Errorf("%s, AddLine: got line count %d; want %d", f.Name(), f.LineCount(), i+1)
   116  			}
   117  			// adding the same offset again should be ignored
   118  			f.AddLine(offset)
   119  			if f.LineCount() != i+1 {
   120  				t.Errorf("%s, AddLine: got unchanged line count %d; want %d", f.Name(), f.LineCount(), i+1)
   121  			}
   122  			verifyPositions(t, fset, f, test.lines[0:i+1])
   123  		}
   124  
   125  		// add lines with SetLines and verify all positions
   126  		if ok := f.SetLines(test.lines); !ok {
   127  			t.Errorf("%s: SetLines failed", f.Name())
   128  		}
   129  		if f.LineCount() != len(test.lines) {
   130  			t.Errorf("%s, SetLines: got line count %d; want %d", f.Name(), f.LineCount(), len(test.lines))
   131  		}
   132  		verifyPositions(t, fset, f, test.lines)
   133  
   134  		// add lines with SetLinesForContent and verify all positions
   135  		src := test.source
   136  		if src == nil {
   137  			// no test source available - create one from scratch
   138  			src = makeTestSource(test.size, test.lines)
   139  		}
   140  		f.SetLinesForContent(src)
   141  		if f.LineCount() != len(test.lines) {
   142  			t.Errorf("%s, SetLinesForContent: got line count %d; want %d", f.Name(), f.LineCount(), len(test.lines))
   143  		}
   144  		verifyPositions(t, fset, f, test.lines)
   145  	}
   146  }
   147  
   148  func TestLineInfo(t *testing.T) {
   149  	fset := NewFileSet()
   150  	f := fset.AddFile("foo", fset.Base(), 500)
   151  	lines := []int{0, 42, 77, 100, 210, 220, 277, 300, 333, 401}
   152  	// add lines individually and provide alternative line information
   153  	for _, offs := range lines {
   154  		f.AddLine(offs)
   155  		f.AddLineInfo(offs, "bar", 42)
   156  	}
   157  	// verify positions for all offsets
   158  	for offs := 0; offs <= f.Size(); offs++ {
   159  		p := f.Pos(offs)
   160  		_, col := linecol(lines, offs)
   161  		msg := fmt.Sprintf("%s (offs = %d, p = %d)", f.Name(), offs, p)
   162  		checkPos(t, msg, f.Position(f.Pos(offs)), Position{"bar", offs, 42, col})
   163  		checkPos(t, msg, fset.Position(p), Position{"bar", offs, 42, col})
   164  	}
   165  }
   166  
   167  func TestFiles(t *testing.T) {
   168  	fset := NewFileSet()
   169  	for i, test := range tests {
   170  		base := fset.Base()
   171  		if i%2 == 1 {
   172  			// Setting a negative base is equivalent to
   173  			// fset.Base(), so test some of each.
   174  			base = -1
   175  		}
   176  		fset.AddFile(test.filename, base, test.size)
   177  		j := 0
   178  		fset.Iterate(func(f *File) bool {
   179  			if f.Name() != tests[j].filename {
   180  				t.Errorf("got filename = %s; want %s", f.Name(), tests[j].filename)
   181  			}
   182  			j++
   183  			return true
   184  		})
   185  		if j != i+1 {
   186  			t.Errorf("got %d files; want %d", j, i+1)
   187  		}
   188  	}
   189  }
   190  
   191  // FileSet.File should return nil if Pos is past the end of the FileSet.
   192  func TestFileSetPastEnd(t *testing.T) {
   193  	fset := NewFileSet()
   194  	for _, test := range tests {
   195  		fset.AddFile(test.filename, fset.Base(), test.size)
   196  	}
   197  	if f := fset.File(Pos(fset.Base())); f != nil {
   198  		t.Errorf("got %v, want nil", f)
   199  	}
   200  }
   201  
   202  func TestFileSetCacheUnlikely(t *testing.T) {
   203  	fset := NewFileSet()
   204  	offsets := make(map[string]int)
   205  	for _, test := range tests {
   206  		offsets[test.filename] = fset.Base()
   207  		fset.AddFile(test.filename, fset.Base(), test.size)
   208  	}
   209  	for file, pos := range offsets {
   210  		f := fset.File(Pos(pos))
   211  		if f.Name() != file {
   212  			t.Errorf("got %q at position %d, want %q", f.Name(), pos, file)
   213  		}
   214  	}
   215  }
   216  
   217  // issue 4345. Test that concurrent use of FileSet.Pos does not trigger a
   218  // race in the FileSet position cache.
   219  func TestFileSetRace(t *testing.T) {
   220  	fset := NewFileSet()
   221  	for i := 0; i < 100; i++ {
   222  		fset.AddFile(fmt.Sprintf("file-%d", i), fset.Base(), 1031)
   223  	}
   224  	max := int32(fset.Base())
   225  	var stop sync.WaitGroup
   226  	r := rand.New(rand.NewSource(7))
   227  	for i := 0; i < 2; i++ {
   228  		r := rand.New(rand.NewSource(r.Int63()))
   229  		stop.Add(1)
   230  		go func() {
   231  			for i := 0; i < 1000; i++ {
   232  				fset.Position(Pos(r.Int31n(max)))
   233  			}
   234  			stop.Done()
   235  		}()
   236  	}
   237  	stop.Wait()
   238  }
   239  
   240  // issue 16548. Test that concurrent use of File.AddLine and FileSet.PositionFor
   241  // does not trigger a race in the FileSet position cache.
   242  func TestFileSetRace2(t *testing.T) {
   243  	const N = 1e3
   244  	var (
   245  		fset = NewFileSet()
   246  		file = fset.AddFile("", -1, N)
   247  		ch   = make(chan int, 2)
   248  	)
   249  
   250  	go func() {
   251  		for i := 0; i < N; i++ {
   252  			file.AddLine(i)
   253  		}
   254  		ch <- 1
   255  	}()
   256  
   257  	go func() {
   258  		pos := file.Pos(0)
   259  		for i := 0; i < N; i++ {
   260  			fset.PositionFor(pos, false)
   261  		}
   262  		ch <- 1
   263  	}()
   264  
   265  	<-ch
   266  	<-ch
   267  }
   268  
   269  func TestPositionFor(t *testing.T) {
   270  	src := []byte(`
   271  foo
   272  b
   273  ar
   274  //line :100
   275  foobar
   276  //line bar:3
   277  done
   278  `)
   279  
   280  	const filename = "foo"
   281  	fset := NewFileSet()
   282  	f := fset.AddFile(filename, fset.Base(), len(src))
   283  	f.SetLinesForContent(src)
   284  
   285  	// verify position info
   286  	for i, offs := range f.lines {
   287  		got1 := f.PositionFor(f.Pos(offs), false)
   288  		got2 := f.PositionFor(f.Pos(offs), true)
   289  		got3 := f.Position(f.Pos(offs))
   290  		want := Position{filename, offs, i + 1, 1}
   291  		checkPos(t, "1. PositionFor unadjusted", got1, want)
   292  		checkPos(t, "1. PositionFor adjusted", got2, want)
   293  		checkPos(t, "1. Position", got3, want)
   294  	}
   295  
   296  	// manually add //line info on lines l1, l2
   297  	const l1, l2 = 5, 7
   298  	f.AddLineInfo(f.lines[l1-1], "", 100)
   299  	f.AddLineInfo(f.lines[l2-1], "bar", 3)
   300  
   301  	// unadjusted position info must remain unchanged
   302  	for i, offs := range f.lines {
   303  		got1 := f.PositionFor(f.Pos(offs), false)
   304  		want := Position{filename, offs, i + 1, 1}
   305  		checkPos(t, "2. PositionFor unadjusted", got1, want)
   306  	}
   307  
   308  	// adjusted position info should have changed
   309  	for i, offs := range f.lines {
   310  		got2 := f.PositionFor(f.Pos(offs), true)
   311  		got3 := f.Position(f.Pos(offs))
   312  		want := Position{filename, offs, i + 1, 1}
   313  		// manually compute wanted filename and line
   314  		line := want.Line
   315  		if i+1 >= l1 {
   316  			want.Filename = ""
   317  			want.Line = line - l1 + 100
   318  		}
   319  		if i+1 >= l2 {
   320  			want.Filename = "bar"
   321  			want.Line = line - l2 + 3
   322  		}
   323  		checkPos(t, "3. PositionFor adjusted", got2, want)
   324  		checkPos(t, "3. Position", got3, want)
   325  	}
   326  }
   327  

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