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Source file src/go/token/position_test.go

Documentation: go/token

  // Copyright 2010 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package token
  
  import (
  	"fmt"
  	"math/rand"
  	"sync"
  	"testing"
  )
  
  func checkPos(t *testing.T, msg string, got, want Position) {
  	if got.Filename != want.Filename {
  		t.Errorf("%s: got filename = %q; want %q", msg, got.Filename, want.Filename)
  	}
  	if got.Offset != want.Offset {
  		t.Errorf("%s: got offset = %d; want %d", msg, got.Offset, want.Offset)
  	}
  	if got.Line != want.Line {
  		t.Errorf("%s: got line = %d; want %d", msg, got.Line, want.Line)
  	}
  	if got.Column != want.Column {
  		t.Errorf("%s: got column = %d; want %d", msg, got.Column, want.Column)
  	}
  }
  
  func TestNoPos(t *testing.T) {
  	if NoPos.IsValid() {
  		t.Errorf("NoPos should not be valid")
  	}
  	var fset *FileSet
  	checkPos(t, "nil NoPos", fset.Position(NoPos), Position{})
  	fset = NewFileSet()
  	checkPos(t, "fset NoPos", fset.Position(NoPos), Position{})
  }
  
  var tests = []struct {
  	filename string
  	source   []byte // may be nil
  	size     int
  	lines    []int
  }{
  	{"a", []byte{}, 0, []int{}},
  	{"b", []byte("01234"), 5, []int{0}},
  	{"c", []byte("\n\n\n\n\n\n\n\n\n"), 9, []int{0, 1, 2, 3, 4, 5, 6, 7, 8}},
  	{"d", nil, 100, []int{0, 5, 10, 20, 30, 70, 71, 72, 80, 85, 90, 99}},
  	{"e", nil, 777, []int{0, 80, 100, 120, 130, 180, 267, 455, 500, 567, 620}},
  	{"f", []byte("package p\n\nimport \"fmt\""), 23, []int{0, 10, 11}},
  	{"g", []byte("package p\n\nimport \"fmt\"\n"), 24, []int{0, 10, 11}},
  	{"h", []byte("package p\n\nimport \"fmt\"\n "), 25, []int{0, 10, 11, 24}},
  }
  
  func linecol(lines []int, offs int) (int, int) {
  	prevLineOffs := 0
  	for line, lineOffs := range lines {
  		if offs < lineOffs {
  			return line, offs - prevLineOffs + 1
  		}
  		prevLineOffs = lineOffs
  	}
  	return len(lines), offs - prevLineOffs + 1
  }
  
  func verifyPositions(t *testing.T, fset *FileSet, f *File, lines []int) {
  	for offs := 0; offs < f.Size(); offs++ {
  		p := f.Pos(offs)
  		offs2 := f.Offset(p)
  		if offs2 != offs {
  			t.Errorf("%s, Offset: got offset %d; want %d", f.Name(), offs2, offs)
  		}
  		line, col := linecol(lines, offs)
  		msg := fmt.Sprintf("%s (offs = %d, p = %d)", f.Name(), offs, p)
  		checkPos(t, msg, f.Position(f.Pos(offs)), Position{f.Name(), offs, line, col})
  		checkPos(t, msg, fset.Position(p), Position{f.Name(), offs, line, col})
  	}
  }
  
  func makeTestSource(size int, lines []int) []byte {
  	src := make([]byte, size)
  	for _, offs := range lines {
  		if offs > 0 {
  			src[offs-1] = '\n'
  		}
  	}
  	return src
  }
  
  func TestPositions(t *testing.T) {
  	const delta = 7 // a non-zero base offset increment
  	fset := NewFileSet()
  	for _, test := range tests {
  		// verify consistency of test case
  		if test.source != nil && len(test.source) != test.size {
  			t.Errorf("%s: inconsistent test case: got file size %d; want %d", test.filename, len(test.source), test.size)
  		}
  
  		// add file and verify name and size
  		f := fset.AddFile(test.filename, fset.Base()+delta, test.size)
  		if f.Name() != test.filename {
  			t.Errorf("got filename %q; want %q", f.Name(), test.filename)
  		}
  		if f.Size() != test.size {
  			t.Errorf("%s: got file size %d; want %d", f.Name(), f.Size(), test.size)
  		}
  		if fset.File(f.Pos(0)) != f {
  			t.Errorf("%s: f.Pos(0) was not found in f", f.Name())
  		}
  
  		// add lines individually and verify all positions
  		for i, offset := range test.lines {
  			f.AddLine(offset)
  			if f.LineCount() != i+1 {
  				t.Errorf("%s, AddLine: got line count %d; want %d", f.Name(), f.LineCount(), i+1)
  			}
  			// adding the same offset again should be ignored
  			f.AddLine(offset)
  			if f.LineCount() != i+1 {
  				t.Errorf("%s, AddLine: got unchanged line count %d; want %d", f.Name(), f.LineCount(), i+1)
  			}
  			verifyPositions(t, fset, f, test.lines[0:i+1])
  		}
  
  		// add lines with SetLines and verify all positions
  		if ok := f.SetLines(test.lines); !ok {
  			t.Errorf("%s: SetLines failed", f.Name())
  		}
  		if f.LineCount() != len(test.lines) {
  			t.Errorf("%s, SetLines: got line count %d; want %d", f.Name(), f.LineCount(), len(test.lines))
  		}
  		verifyPositions(t, fset, f, test.lines)
  
  		// add lines with SetLinesForContent and verify all positions
  		src := test.source
  		if src == nil {
  			// no test source available - create one from scratch
  			src = makeTestSource(test.size, test.lines)
  		}
  		f.SetLinesForContent(src)
  		if f.LineCount() != len(test.lines) {
  			t.Errorf("%s, SetLinesForContent: got line count %d; want %d", f.Name(), f.LineCount(), len(test.lines))
  		}
  		verifyPositions(t, fset, f, test.lines)
  	}
  }
  
  func TestLineInfo(t *testing.T) {
  	fset := NewFileSet()
  	f := fset.AddFile("foo", fset.Base(), 500)
  	lines := []int{0, 42, 77, 100, 210, 220, 277, 300, 333, 401}
  	// add lines individually and provide alternative line information
  	for _, offs := range lines {
  		f.AddLine(offs)
  		f.AddLineInfo(offs, "bar", 42)
  	}
  	// verify positions for all offsets
  	for offs := 0; offs <= f.Size(); offs++ {
  		p := f.Pos(offs)
  		_, col := linecol(lines, offs)
  		msg := fmt.Sprintf("%s (offs = %d, p = %d)", f.Name(), offs, p)
  		checkPos(t, msg, f.Position(f.Pos(offs)), Position{"bar", offs, 42, col})
  		checkPos(t, msg, fset.Position(p), Position{"bar", offs, 42, col})
  	}
  }
  
  func TestFiles(t *testing.T) {
  	fset := NewFileSet()
  	for i, test := range tests {
  		base := fset.Base()
  		if i%2 == 1 {
  			// Setting a negative base is equivalent to
  			// fset.Base(), so test some of each.
  			base = -1
  		}
  		fset.AddFile(test.filename, base, test.size)
  		j := 0
  		fset.Iterate(func(f *File) bool {
  			if f.Name() != tests[j].filename {
  				t.Errorf("got filename = %s; want %s", f.Name(), tests[j].filename)
  			}
  			j++
  			return true
  		})
  		if j != i+1 {
  			t.Errorf("got %d files; want %d", j, i+1)
  		}
  	}
  }
  
  // FileSet.File should return nil if Pos is past the end of the FileSet.
  func TestFileSetPastEnd(t *testing.T) {
  	fset := NewFileSet()
  	for _, test := range tests {
  		fset.AddFile(test.filename, fset.Base(), test.size)
  	}
  	if f := fset.File(Pos(fset.Base())); f != nil {
  		t.Errorf("got %v, want nil", f)
  	}
  }
  
  func TestFileSetCacheUnlikely(t *testing.T) {
  	fset := NewFileSet()
  	offsets := make(map[string]int)
  	for _, test := range tests {
  		offsets[test.filename] = fset.Base()
  		fset.AddFile(test.filename, fset.Base(), test.size)
  	}
  	for file, pos := range offsets {
  		f := fset.File(Pos(pos))
  		if f.Name() != file {
  			t.Errorf("got %q at position %d, want %q", f.Name(), pos, file)
  		}
  	}
  }
  
  // issue 4345. Test that concurrent use of FileSet.Pos does not trigger a
  // race in the FileSet position cache.
  func TestFileSetRace(t *testing.T) {
  	fset := NewFileSet()
  	for i := 0; i < 100; i++ {
  		fset.AddFile(fmt.Sprintf("file-%d", i), fset.Base(), 1031)
  	}
  	max := int32(fset.Base())
  	var stop sync.WaitGroup
  	r := rand.New(rand.NewSource(7))
  	for i := 0; i < 2; i++ {
  		r := rand.New(rand.NewSource(r.Int63()))
  		stop.Add(1)
  		go func() {
  			for i := 0; i < 1000; i++ {
  				fset.Position(Pos(r.Int31n(max)))
  			}
  			stop.Done()
  		}()
  	}
  	stop.Wait()
  }
  
  // issue 16548. Test that concurrent use of File.AddLine and FileSet.PositionFor
  // does not trigger a race in the FileSet position cache.
  func TestFileSetRace2(t *testing.T) {
  	const N = 1e3
  	var (
  		fset = NewFileSet()
  		file = fset.AddFile("", -1, N)
  		ch   = make(chan int, 2)
  	)
  
  	go func() {
  		for i := 0; i < N; i++ {
  			file.AddLine(i)
  		}
  		ch <- 1
  	}()
  
  	go func() {
  		pos := file.Pos(0)
  		for i := 0; i < N; i++ {
  			fset.PositionFor(pos, false)
  		}
  		ch <- 1
  	}()
  
  	<-ch
  	<-ch
  }
  
  func TestPositionFor(t *testing.T) {
  	src := []byte(`
  foo
  b
  ar
  //line :100
  foobar
  //line bar:3
  done
  `)
  
  	const filename = "foo"
  	fset := NewFileSet()
  	f := fset.AddFile(filename, fset.Base(), len(src))
  	f.SetLinesForContent(src)
  
  	// verify position info
  	for i, offs := range f.lines {
  		got1 := f.PositionFor(f.Pos(offs), false)
  		got2 := f.PositionFor(f.Pos(offs), true)
  		got3 := f.Position(f.Pos(offs))
  		want := Position{filename, offs, i + 1, 1}
  		checkPos(t, "1. PositionFor unadjusted", got1, want)
  		checkPos(t, "1. PositionFor adjusted", got2, want)
  		checkPos(t, "1. Position", got3, want)
  	}
  
  	// manually add //line info on lines l1, l2
  	const l1, l2 = 5, 7
  	f.AddLineInfo(f.lines[l1-1], "", 100)
  	f.AddLineInfo(f.lines[l2-1], "bar", 3)
  
  	// unadjusted position info must remain unchanged
  	for i, offs := range f.lines {
  		got1 := f.PositionFor(f.Pos(offs), false)
  		want := Position{filename, offs, i + 1, 1}
  		checkPos(t, "2. PositionFor unadjusted", got1, want)
  	}
  
  	// adjusted position info should have changed
  	for i, offs := range f.lines {
  		got2 := f.PositionFor(f.Pos(offs), true)
  		got3 := f.Position(f.Pos(offs))
  		want := Position{filename, offs, i + 1, 1}
  		// manually compute wanted filename and line
  		line := want.Line
  		if i+1 >= l1 {
  			want.Filename = ""
  			want.Line = line - l1 + 100
  		}
  		if i+1 >= l2 {
  			want.Filename = "bar"
  			want.Line = line - l2 + 3
  		}
  		checkPos(t, "3. PositionFor adjusted", got2, want)
  		checkPos(t, "3. Position", got3, want)
  	}
  }
  

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