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-rw-r--r--plumbing/format/diff/unified_encoder.go355
1 files changed, 355 insertions, 0 deletions
diff --git a/plumbing/format/diff/unified_encoder.go b/plumbing/format/diff/unified_encoder.go
new file mode 100644
index 0000000..a4ff7ab
--- /dev/null
+++ b/plumbing/format/diff/unified_encoder.go
@@ -0,0 +1,355 @@
+package diff
+
+import (
+ "bytes"
+ "errors"
+ "fmt"
+ "io"
+ "strings"
+
+ "gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+const (
+ diffInit = "diff --git a/%s b/%s\n"
+
+ chunkStart = "@@ -"
+ chunkMiddle = " +"
+ chunkEnd = " @@%s\n"
+ chunkCount = "%d,%d"
+
+ noFilePath = "/dev/null"
+ aDir = "a/"
+ bDir = "b/"
+
+ fPath = "--- %s\n"
+ tPath = "+++ %s\n"
+ binary = "Binary files %s and %s differ\n"
+
+ addLine = "+%s\n"
+ deleteLine = "-%s\n"
+ equalLine = " %s\n"
+
+ oldMode = "old mode %o\n"
+ newMode = "new mode %o\n"
+ deletedFileMode = "deleted file mode %o\n"
+ newFileMode = "new file mode %o\n"
+
+ renameFrom = "from"
+ renameTo = "to"
+ renameFileMode = "rename %s %s\n"
+
+ indexAndMode = "index %s..%s %o\n"
+ indexNoMode = "index %s..%s\n"
+
+ DefaultContextLines = 3
+)
+
+var ErrBothFilesEmpty = errors.New("both files are empty")
+
+// UnifiedEncoder encodes an unified diff into the provided Writer.
+// There are some unsupported features:
+// - Similarity index for renames
+// - Sort hash representation
+type UnifiedEncoder struct {
+ io.Writer
+
+ // ctxLines is the count of unchanged lines that will appear
+ // surrounding a change.
+ ctxLines int
+
+ buf bytes.Buffer
+}
+
+func NewUnifiedEncoder(w io.Writer, ctxLines int) *UnifiedEncoder {
+ return &UnifiedEncoder{ctxLines: ctxLines, Writer: w}
+}
+
+func (e *UnifiedEncoder) Encode(patch Patch) error {
+ e.printMessage(patch.Message())
+
+ if err := e.encodeFilePatch(patch.FilePatches()); err != nil {
+ return err
+ }
+
+ _, err := e.buf.WriteTo(e)
+
+ return err
+}
+
+func (e *UnifiedEncoder) encodeFilePatch(filePatches []FilePatch) error {
+ for _, p := range filePatches {
+ f, t := p.Files()
+ if err := e.header(f, t, p.IsBinary()); err != nil {
+ return err
+ }
+
+ g := newHunksGenerator(p.Chunks(), e.ctxLines)
+ for _, c := range g.Generate() {
+ c.WriteTo(&e.buf)
+ }
+ }
+
+ return nil
+}
+
+func (e *UnifiedEncoder) printMessage(message string) {
+ isEmpty := message == ""
+ hasSuffix := strings.HasSuffix(message, "\n")
+ if !isEmpty && !hasSuffix {
+ message = message + "\n"
+ }
+
+ e.buf.WriteString(message)
+}
+
+func (e *UnifiedEncoder) header(from, to File, isBinary bool) error {
+ switch {
+ case from == nil && to == nil:
+ return ErrBothFilesEmpty
+ case from != nil && to != nil:
+ hashEquals := from.Hash() == to.Hash()
+
+ fmt.Fprintf(&e.buf, diffInit, from.Path(), to.Path())
+
+ if from.Mode() != to.Mode() {
+ fmt.Fprintf(&e.buf, oldMode+newMode, from.Mode(), to.Mode())
+ }
+
+ if from.Path() != to.Path() {
+ fmt.Fprintf(&e.buf,
+ renameFileMode+renameFileMode,
+ renameFrom, from.Path(), renameTo, to.Path())
+ }
+
+ if from.Mode() != to.Mode() && !hashEquals {
+ fmt.Fprintf(&e.buf, indexNoMode, from.Hash(), to.Hash())
+ } else if !hashEquals {
+ fmt.Fprintf(&e.buf, indexAndMode, from.Hash(), to.Hash(), from.Mode())
+ }
+
+ if !hashEquals {
+ e.pathLines(isBinary, aDir+from.Path(), bDir+to.Path())
+ }
+ case from == nil:
+ fmt.Fprintf(&e.buf, diffInit, to.Path(), to.Path())
+ fmt.Fprintf(&e.buf, newFileMode, to.Mode())
+ fmt.Fprintf(&e.buf, indexNoMode, plumbing.ZeroHash, to.Hash())
+ e.pathLines(isBinary, noFilePath, bDir+to.Path())
+ case to == nil:
+ fmt.Fprintf(&e.buf, diffInit, from.Path(), from.Path())
+ fmt.Fprintf(&e.buf, deletedFileMode, from.Mode())
+ fmt.Fprintf(&e.buf, indexNoMode, from.Hash(), plumbing.ZeroHash)
+ e.pathLines(isBinary, aDir+from.Path(), noFilePath)
+ }
+
+ return nil
+}
+
+func (e *UnifiedEncoder) pathLines(isBinary bool, fromPath, toPath string) {
+ format := fPath + tPath
+ if isBinary {
+ format = binary
+ }
+
+ fmt.Fprintf(&e.buf, format, fromPath, toPath)
+}
+
+type hunksGenerator struct {
+ fromLine, toLine int
+ ctxLines int
+ chunks []Chunk
+ current *hunk
+ hunks []*hunk
+ beforeContext, afterContext []string
+}
+
+func newHunksGenerator(chunks []Chunk, ctxLines int) *hunksGenerator {
+ return &hunksGenerator{
+ chunks: chunks,
+ ctxLines: ctxLines,
+ }
+}
+
+func (c *hunksGenerator) Generate() []*hunk {
+ for i, chunk := range c.chunks {
+ ls := splitLines(chunk.Content())
+ lsLen := len(ls)
+
+ switch chunk.Type() {
+ case Equal:
+ c.fromLine += lsLen
+ c.toLine += lsLen
+ c.processEqualsLines(ls, i)
+ case Delete:
+ if lsLen != 0 {
+ c.fromLine++
+ }
+
+ c.processHunk(i, chunk.Type())
+ c.fromLine += lsLen - 1
+ c.current.AddOp(chunk.Type(), ls...)
+ case Add:
+ if lsLen != 0 {
+ c.toLine++
+ }
+ c.processHunk(i, chunk.Type())
+ c.toLine += lsLen - 1
+ c.current.AddOp(chunk.Type(), ls...)
+ }
+
+ if i == len(c.chunks)-1 && c.current != nil {
+ c.hunks = append(c.hunks, c.current)
+ }
+ }
+
+ return c.hunks
+}
+
+func (c *hunksGenerator) processHunk(i int, op Operation) {
+ if c.current != nil {
+ return
+ }
+
+ var ctxPrefix string
+ linesBefore := len(c.beforeContext)
+ if linesBefore > c.ctxLines {
+ ctxPrefix = " " + c.beforeContext[linesBefore-c.ctxLines-1]
+ c.beforeContext = c.beforeContext[linesBefore-c.ctxLines:]
+ linesBefore = c.ctxLines
+ }
+
+ c.current = &hunk{ctxPrefix: ctxPrefix}
+ c.current.AddOp(Equal, c.beforeContext...)
+
+ switch op {
+ case Delete:
+ c.current.fromLine, c.current.toLine =
+ c.addLineNumbers(c.fromLine, c.toLine, linesBefore, i, Add)
+ case Add:
+ c.current.toLine, c.current.fromLine =
+ c.addLineNumbers(c.toLine, c.fromLine, linesBefore, i, Delete)
+ }
+
+ c.beforeContext = nil
+}
+
+// addLineNumbers obtains the line numbers in a new chunk
+func (c *hunksGenerator) addLineNumbers(la, lb int, linesBefore int, i int, op Operation) (cla, clb int) {
+ cla = la - linesBefore
+ // we need to search for a reference for the next diff
+ switch {
+ case linesBefore != 0 && c.ctxLines != 0:
+ clb = lb - c.ctxLines + 1
+ case c.ctxLines == 0:
+ clb = lb - c.ctxLines
+ case i != len(c.chunks)-1:
+ next := c.chunks[i+1]
+ if next.Type() == op || next.Type() == Equal {
+ // this diff will be into this chunk
+ clb = lb + 1
+ }
+ }
+
+ return
+}
+
+func (c *hunksGenerator) processEqualsLines(ls []string, i int) {
+ if c.current == nil {
+ c.beforeContext = append(c.beforeContext, ls...)
+ return
+ }
+
+ c.afterContext = append(c.afterContext, ls...)
+ if len(c.afterContext) <= c.ctxLines*2 && i != len(c.chunks)-1 {
+ c.current.AddOp(Equal, c.afterContext...)
+ c.afterContext = nil
+ } else {
+ c.current.AddOp(Equal, c.afterContext[:c.ctxLines]...)
+ c.hunks = append(c.hunks, c.current)
+
+ c.current = nil
+ c.beforeContext = c.afterContext[c.ctxLines:]
+ c.afterContext = nil
+ }
+}
+
+func splitLines(s string) []string {
+ out := strings.Split(s, "\n")
+ if out[len(out)-1] == "" {
+ out = out[:len(out)-1]
+ }
+
+ return out
+}
+
+type hunk struct {
+ fromLine int
+ toLine int
+
+ fromCount int
+ toCount int
+
+ ctxPrefix string
+ ops []*op
+}
+
+func (c *hunk) WriteTo(buf *bytes.Buffer) {
+ buf.WriteString(chunkStart)
+
+ if c.fromCount == 1 {
+ fmt.Fprintf(buf, "%d", c.fromLine)
+ } else {
+ fmt.Fprintf(buf, chunkCount, c.fromLine, c.fromCount)
+ }
+
+ buf.WriteString(chunkMiddle)
+
+ if c.toCount == 1 {
+ fmt.Fprintf(buf, "%d", c.toLine)
+ } else {
+ fmt.Fprintf(buf, chunkCount, c.toLine, c.toCount)
+ }
+
+ fmt.Fprintf(buf, chunkEnd, c.ctxPrefix)
+
+ for _, d := range c.ops {
+ buf.WriteString(d.String())
+ }
+}
+
+func (c *hunk) AddOp(t Operation, s ...string) {
+ ls := len(s)
+ switch t {
+ case Add:
+ c.toCount += ls
+ case Delete:
+ c.fromCount += ls
+ case Equal:
+ c.toCount += ls
+ c.fromCount += ls
+ }
+
+ for _, l := range s {
+ c.ops = append(c.ops, &op{l, t})
+ }
+}
+
+type op struct {
+ text string
+ t Operation
+}
+
+func (o *op) String() string {
+ var prefix string
+ switch o.t {
+ case Add:
+ prefix = addLine
+ case Delete:
+ prefix = deleteLine
+ case Equal:
+ prefix = equalLine
+ }
+
+ return fmt.Sprintf(prefix, o.text)
+}
generated by cgit (git 2.34.1) at 2024-09-22 07:27:31 +0000