Accept "git diff" as input

In addition to supporting file list input, this commit adds support for
raw "git diff" output. In this case, only the changed files will appear,
and only the lines marked as "added" in the diff will be shown. For
every such line, its coverage status will be reported of course
(red/green/gray).

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

@@ -46,6 +46,10 @@ 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))
 )
 
 // New creates a new codeview model which is rendered into the provided width
@@ -60,13 +64,14 @@ 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 []int
+	showHelp      bool
 }
 
 // Update is used to update the internal model state based on the external
@@ -115,6 +120,14 @@ 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 = filteredLines
+	m.redrawLines()
+	m.viewport.SetYOffset(0)
+}
+
 func (m *Model) redrawLines() {
 	content := m.formatLines(m.lines)
 	m.viewport.SetContent(content)
@@ -201,22 +214,47 @@ func (m *Model) recalculateSize() {
 }
 
 func (m *Model) formatLines(lines []string) string {
+	if len(lines) == 0 {
+		return ""
+	}
+
 	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)
+	filterApplied := len(m.filteredLines) > 0
 
-	var buf strings.Builder
+	var (
+		buf             strings.Builder
+		printSingleLine = func(line string, number int) {
+			line = m.replaceTabsWithSpaces(line)
+			lineNumber := lineNumberStyle.Render(fmt.Sprintf("%d", number))
 
-	for i, line := range lines {
-		line = m.replaceTabsWithSpaces(line)
-		lineNumber := lineNumberStyle.Render(fmt.Sprintf("%d", i+1))
+			if lipgloss.Width(line) > availableWidth {
+				line = truncate.StringWithTail(line, uint(availableWidth), ellipsis)
+			}
 
-		if lipgloss.Width(line) > availableWidth {
-			line = truncate.StringWithTail(line, uint(availableWidth), ellipsis)
+			buf.WriteString(lipgloss.JoinHorizontal(lipgloss.Left, lineNumber, line))
+			buf.WriteString(newLine)
 		}
+	)
+
+	if filterApplied {
+		lastPrintedLine := 0
+		separator := blankBlockSeparatorStyle.Render(strings.Repeat("─", max(0, m.width)))
+
+		for _, thisLine := range m.filteredLines {
+			if thisLine-lastPrintedLine > 1 {
+				buf.WriteString(separator)
+				buf.WriteString(newLine)
+			}
 
-		buf.WriteString(lipgloss.JoinHorizontal(lipgloss.Left, lineNumber, line))
-		buf.WriteString(newLine)
+			printSingleLine(lines[thisLine-1], thisLine)
+			lastPrintedLine = thisLine
+		}
+	} else {
+		for i, line := range lines {
+			printSingleLine(line, i+1)
+		}
 	}
 
 	return buf.String()

internal/model/model.go

@@ -79,6 +79,7 @@ type Model struct {
 	sortByCoverage      bool
 	detectedPackageName string
 	requestedFiles      map[string]bool
+	filteredLinesByFile map[string][]int
 
 	activeView viewName
 	helpState  helpState
@@ -257,6 +258,7 @@ func (m *Model) onKeyPressed(key string) (tea.Model, tea.Cmd) {
 		item, ok := m.list.SelectedItem().(*coverProfile)
 		if ok {
 			m.code.SetTitle(item.profile.FileName)
+			m.code.SetFilteredLines(m.filteredLinesByFile[item.profile.FileName])
 
 			adjustedFileName := path.Join(m.codeRoot, item.profile.FileName)
 

internal/model/options.go

@@ -34,3 +34,25 @@ func WithRequestedFiles(files []string) Option {
 		}
 	}
 }
+
+// WithFilteredLines sets a list of lines to display for every file. Other
+// lines will not appear.
+func WithFilteredLines(files map[string][]int) Option {
+	return func(m *Model) {
+		m.filteredLinesByFile = make(map[string][]int, len(files))
+		uniqueLines := map[int]interface{}{}
+
+		for file, lines := range files {
+			linesWithContext := make([]int, 0, len(lines))
+
+			for _, line := range lines {
+				if _, ok := uniqueLines[line]; !ok {
+					linesWithContext = append(linesWithContext, line)
+					uniqueLines[line] = nil
+				}
+			}
+
+			m.filteredLinesByFile[file] = linesWithContext
+		}
+	}
+}

internal/program/program.go

@@ -13,6 +13,7 @@ import (
 
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/orlangure/gocovsh/internal/model"
+	"github.com/waigani/diffparser"
 )
 
 const (
@@ -72,12 +73,14 @@ type Program struct {
 	profileFilename string
 	sortByCoverage  bool
 
-	flagSet        *flag.FlagSet
-	args           []string
-	input          fs.File
-	output         io.Writer
-	logFile        string
+	flagSet *flag.FlagSet
+	args    []string
+	input   fs.File
+	output  io.Writer
+	logFile string
+
 	requestedFiles []string
+	diffLines      map[string][]int
 }
 
 // Run parses the command line arguments and runs the program.
@@ -111,6 +114,7 @@ func (p *Program) Run() error {
 		model.WithProfileFilename(p.profileFilename),
 		model.WithRequestedFiles(p.requestedFiles),
 		model.WithCoverageSorting(p.sortByCoverage),
+		model.WithFilteredLines(p.diffLines),
 	)
 
 	if p.logFile != "" {
@@ -140,7 +144,22 @@ func (p *Program) parseInput() error {
 			return fmt.Errorf("failed to read stdin: %w", err)
 		}
 
-		p.requestedFiles = p.splitLines(string(bs))
+		if diff, err := diffparser.Parse(string(bs)); err != nil {
+			// fall back to file list mode - this is not an error
+			p.requestedFiles = p.splitLines(string(bs))
+		} else {
+			p.diffLines = diff.Changed()
+
+			for file := range p.diffLines {
+				if !strings.HasSuffix(file, ".go") {
+					delete(p.diffLines, file)
+				}
+			}
+
+			for _, file := range diff.Files {
+				p.requestedFiles = append(p.requestedFiles, file.NewName)
+			}
+		}
 	}
 
 	return nil