Accept git diff as input

This commit allows to pipe `git diff` command output into gocovsh to
display only changed portions of changed files. It might be helpful when
actively working on a feature to determine its coverage quickly, while
disregarding the rest of the code.

.gitignore

@@ -15,3 +15,4 @@
 # vendor/
 
 dist/
+gocovsh

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/muesli/termenv v0.9.0
 	github.com/sebdah/goldie/v2 v2.5.3
 	github.com/stretchr/testify v1.7.0
+	github.com/waigani/diffparser v0.0.0-20190828052634-7391f219313d
 	golang.org/x/tools v0.1.8
 )
 

go.sum

@@ -51,8 +51,11 @@ github.com/sergi/go-diff v1.0.0 h1:Kpca3qRNrduNnOQeazBd0ysaKrUJiIuISHxogkT9RPQ=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/waigani/diffparser v0.0.0-20190828052634-7391f219313d h1:xQcF7b7cZLWZG/+7A4G7un1qmEDYHIvId9qxRS1mZMs=
+github.com/waigani/diffparser v0.0.0-20190828052634-7391f219313d/go.mod h1:BzSc3WEF8R+lCaP5iGFRxd5kIXy4JKOZAwNe1w0cdc0=
 github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -88,5 +91,6 @@ golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8T
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/codeview/code.go

@@ -13,6 +13,7 @@ import (
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 	"github.com/muesli/reflow/truncate"
+	"github.com/orlangure/gocovsh/internal/styles"
 )
 
 const (
@@ -46,8 +47,17 @@ var (
 					Align(lipgloss.Right).
 					BorderForeground(lipgloss.Color(lineNumberColor)).
 					Border(lipgloss.NormalBorder(), false, true, false, false)
+
+	blankBlockSeparatorStyle = lipgloss.NewStyle().
+					MarginTop(1).MarginBottom(1).
+					Foreground(lipgloss.Color(lineNumberColor))
 )
 
+type filteredLines struct {
+	actualLines  []int
+	contextLines map[int]bool
+}
+
 // New creates a new codeview model which is rendered into the provided width
 // and height.
 func New(width, height int) Model {
@@ -60,13 +70,14 @@ func New(width, height int) Model {
 
 // Model is the codeview model. Use New to create a new instance.
 type Model struct {
-	viewport viewport.Model
-	help     help.Model
-	width    int
-	height   int
-	title    string
-	lines    []string
-	showHelp bool
+	viewport      viewport.Model
+	help          help.Model
+	width         int
+	height        int
+	title         string
+	lines         []string
+	filteredLines filteredLines
+	showHelp      bool
 }
 
 // Update is used to update the internal model state based on the external
@@ -115,6 +126,14 @@ func (m *Model) SetContent(lines []string) {
 	m.viewport.SetYOffset(0)
 }
 
+// SetFilteredLines sets the lines that should be displayed, while all other
+// lines are hidden. If not set, everything is displayed.
+func (m *Model) SetFilteredLines(filteredLines []int) {
+	m.filteredLines = contextifyFilteredLines(filteredLines)
+	m.redrawLines()
+	m.viewport.SetYOffset(0)
+}
+
 func (m *Model) redrawLines() {
 	content := m.formatLines(m.lines)
 	m.viewport.SetContent(content)
@@ -201,25 +220,80 @@ func (m *Model) recalculateSize() {
 }
 
 func (m *Model) formatLines(lines []string) string {
-	lineNumberStyle := lineNumberStylePlaceholder.Copy().Width(len(fmt.Sprintf("%d", len(lines))) + 1)
-	lineNumberPlaceholder := lineNumberStyle.Render(fmt.Sprintf("%d", 1))
-	availableWidth := m.width - lipgloss.Width(lineNumberPlaceholder) - lipgloss.Width(ellipsis)
+	if len(lines) == 0 {
+		return ""
+	}
 
-	var buf strings.Builder
+	var (
+		buf             strings.Builder
+		filterApplied   = len(m.filteredLines.actualLines) > 0
+		numberWidth     = len(fmt.Sprintf("%d", len(lines))) + 1
+		lineNumberStyle = lineNumberStylePlaceholder.Copy().Width(numberWidth)
+		printSingleLine = m.linePrinter(&buf, lineNumberStyle)
+	)
+
+	if filterApplied {
+		lastPrintedLine := 0
+		separator := blankBlockSeparatorStyle.Render(strings.Repeat("─", max(0, m.width)))
+
+		for _, thisLineNumber := range m.filteredLines.actualLines {
+			if thisLineNumber > len(lines) {
+				break
+			}
+
+			if thisLineNumber-lastPrintedLine > 1 {
+				buf.WriteString(separator)
+				buf.WriteString(newLine)
+			}
+
+			drawPlus := false
+			line := lines[thisLineNumber-1]
+
+			if !m.filteredLines.contextLines[thisLineNumber] {
+				drawPlus = true
+			}
+
+			printSingleLine(line, thisLineNumber, drawPlus)
+			lastPrintedLine = thisLineNumber
+		}
+	} else {
+		for i, line := range lines {
+			printSingleLine(line, i+1, false)
+		}
+	}
+
+	return buf.String()
+}
 
-	for i, line := range lines {
+type linePrinterFunc func(line string, number int, drawPlus bool)
+
+func (m *Model) linePrinter(buf *strings.Builder, lineNumberStyle lipgloss.Style) linePrinterFunc {
+	filterApplied := len(m.filteredLines.actualLines) > 0
+	lineNumberPlaceholder := lineNumberStyle.Render("1")
+	availableWidth := m.width - lipgloss.Width(lineNumberPlaceholder) - lipgloss.Width(ellipsis)
+	renderedPlus := styles.CoveredLine.Render("+ ")
+	renderedSpace := styles.NeutralLine.Render("  ")
+
+	return func(line string, number int, drawPlus bool) {
 		line = m.replaceTabsWithSpaces(line)
-		lineNumber := lineNumberStyle.Render(fmt.Sprintf("%d", i+1))
+		lineNumber := lineNumberStyle.Render(fmt.Sprintf("%d", number))
+		prefix := ""
+
+		if filterApplied {
+			if drawPlus {
+				prefix = renderedPlus
+			} else {
+				prefix = renderedSpace
+			}
+		}
 
 		if lipgloss.Width(line) > availableWidth {
 			line = truncate.StringWithTail(line, uint(availableWidth), ellipsis)
 		}
 
-		buf.WriteString(lipgloss.JoinHorizontal(lipgloss.Left, lineNumber, line))
+		buf.WriteString(lipgloss.JoinHorizontal(lipgloss.Left, prefix, lineNumber, line))
 		buf.WriteString(newLine)
 	}
-
-	return buf.String()
 }
 
 func (m *Model) replaceTabsWithSpaces(line string) string {
@@ -261,3 +335,49 @@ func max(a, b int) int {
 
 	return b
 }
+
+func contextifyFilteredLines(input []int) filteredLines {
+	if len(input) == 0 {
+		return filteredLines{
+			actualLines:  input,
+			contextLines: map[int]bool{},
+		}
+	}
+
+	extendedLines := make([]int, 0, len(input)+2)
+	contextLines := make(map[int]bool, 2)
+	lastAddedNumber := input[0]
+
+	beforeFirst := lastAddedNumber - 1
+	if beforeFirst > 0 {
+		extendedLines = append(extendedLines, beforeFirst)
+		contextLines[beforeFirst] = true
+	}
+
+	for _, lineNumber := range input {
+		if lineNumber-lastAddedNumber > 1 {
+			afterLast := lastAddedNumber + 1
+			beforeThis := lineNumber - 1
+
+			extendedLines = append(extendedLines, afterLast)
+			contextLines[afterLast] = true
+
+			if afterLast != beforeThis {
+				extendedLines = append(extendedLines, beforeThis)
+				contextLines[beforeThis] = true
+			}
+		}
+
+		extendedLines = append(extendedLines, lineNumber)
+		lastAddedNumber = lineNumber
+	}
+
+	lineAfterLast := input[len(input)-1] + 1
+	extendedLines = append(extendedLines, lineAfterLast)
+	contextLines[lineAfterLast] = true
+
+	return filteredLines{
+		actualLines:  extendedLines,
+		contextLines: contextLines,
+	}
+}

internal/codeview/code_test.go

@@ -0,0 +1,95 @@
+package codeview
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestContextifyFilteredLines(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		input           []int
+		expectedActual  []int
+		expectedContext map[int]bool
+	}{
+		{
+			input:           []int{},
+			expectedActual:  []int{},
+			expectedContext: map[int]bool{},
+		},
+		{
+			input:           []int{1, 2},
+			expectedActual:  []int{1, 2, 3},
+			expectedContext: map[int]bool{3: true},
+		},
+		{
+			input:           []int{2, 3},
+			expectedActual:  []int{1, 2, 3, 4},
+			expectedContext: map[int]bool{1: true, 4: true},
+		},
+		{
+			input:          []int{2, 3, 20},
+			expectedActual: []int{1, 2, 3, 4, 19, 20, 21},
+			expectedContext: map[int]bool{
+				1: true, 4: true,
+				19: true, 21: true,
+			},
+		},
+		{
+			input:          []int{2, 3, 20, 21},
+			expectedActual: []int{1, 2, 3, 4, 19, 20, 21, 22},
+			expectedContext: map[int]bool{
+				1: true, 4: true,
+				19: true, 22: true,
+			},
+		},
+		{
+			input:          []int{2, 3, 20, 30},
+			expectedActual: []int{1, 2, 3, 4, 19, 20, 21, 29, 30, 31},
+			expectedContext: map[int]bool{
+				1: true, 4: true,
+				19: true, 21: true,
+				29: true, 31: true,
+			},
+		},
+		{
+			input:          []int{2, 3, 20, 22},
+			expectedActual: []int{1, 2, 3, 4, 19, 20, 21, 22, 23},
+			expectedContext: map[int]bool{
+				1: true, 4: true,
+				19: true, 21: true, 23: true,
+			},
+		},
+		{
+			input:          []int{2, 3, 20, 21, 22, 24, 25, 30},
+			expectedActual: []int{1, 2, 3, 4, 19, 20, 21, 22, 23, 24, 25, 26, 29, 30, 31},
+			expectedContext: map[int]bool{
+				1: true, 4: true,
+				19: true, 23: true,
+				26: true,
+				29: true, 31: true,
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("%v", test.input), func(t *testing.T) {
+			output := contextifyFilteredLines(test.input)
+			require.EqualValues(t, test.expectedActual, output.actualLines)
+			require.EqualValues(t, test.expectedContext, output.contextLines)
+		})
+	}
+}
+
+func Range(from, to int) []int {
+	result := make([]int, 0, to-from)
+
+	for i := 0; i <= to; i++ {
+		result = append(result, i)
+	}
+
+	return result
+}

internal/gocovshtest/happy_flow_test.go

@@ -10,15 +10,26 @@ import (
 
 func TestHappyFlow(t *testing.T) {
 	t.Run("no requested files", func(t *testing.T) {
-		testHappyFlow(t, "not-requested", nil)
+		testHappyFlow(t, "not-requested", nil, nil)
 	})
 
 	t.Run("requested files", func(t *testing.T) {
-		testHappyFlow(t, "requested", []string{"covered.go"})
+		testHappyFlow(t, "requested", []string{"covered.go"}, nil)
+	})
+
+	t.Run("filtered lines", func(t *testing.T) {
+		testHappyFlow(
+			t,
+			"filtered",
+			[]string{"covered.go"},
+			map[string][]int{
+				"covered.go": {4},
+			},
+		)
 	})
 }
 
-func testHappyFlow(t *testing.T, prefix string, requestedFiles []string) {
+func testHappyFlow(t *testing.T, prefix string, requestedFiles []string, filteredLines map[string][]int) {
 	dir := path.Join("testdata", "general", prefix)
 	g := goldie.New(t, goldie.WithFixtureDir(dir))
 
@@ -27,6 +38,7 @@ func testHappyFlow(t *testing.T, prefix string, requestedFiles []string) {
 		profileFilename: "profile.cover",
 		codeRoot:        "testdata/general",
 		requestedFiles:  requestedFiles,
+		filteredLines:   filteredLines,
 	}
 
 	t.Run("initial setup", func(t *testing.T) {

internal/gocovshtest/main_test.go

@@ -23,6 +23,7 @@ type modelTest struct {
 	profileFilename string
 	codeRoot        string
 	requestedFiles  []string
+	filteredLines   map[string][]int
 
 	m *model.Model
 }
@@ -32,6 +33,7 @@ func (t *modelTest) init() tea.Cmd {
 		model.WithProfileFilename(t.profileFilename),
 		model.WithCodeRoot(t.codeRoot),
 		model.WithRequestedFiles(t.requestedFiles),
+		model.WithFilteredLines(t.filteredLines),
 	)
 
 	initCmd := t.m.Init()