format/diff: unified diff encoder and public API

- Added Patch interface
- Added a Unified Diff encoder from Patches
- Added Change method to generate Patches
- Added Changes method to generate Patches
- Added Tree method to generate Patches
- Added Commit method to generate Patches

1 files changed, 829 insertions, 0 deletions

diff --git a/plumbing/format/diff/unified_encoder_test.go b/plumbing/format/diff/unified_encoder_test.go
new file mode 100644
index 0000000..b832920
--- /dev/null
+++ b/plumbing/format/diff/unified_encoder_test.go
@@ -0,0 +1,829 @@
+package diff
+
+import (
+	"bytes"
+	"testing"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/filemode"
+
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type UnifiedEncoderTestSuite struct{}
+
+var _ = Suite(&UnifiedEncoderTestSuite{})
+
+func (s *UnifiedEncoderTestSuite) TestBothFilesEmpty(c *C) {
+	buffer := bytes.NewBuffer(nil)
+	e := NewUnifiedEncoder(buffer, 1)
+	err := e.Encode(testPatch{filePatches: []testFilePatch{{}}})
+	c.Assert(err, Equals, ErrBothFilesEmpty)
+}
+
+func (s *UnifiedEncoderTestSuite) TestBinaryFile(c *C) {
+	buffer := bytes.NewBuffer(nil)
+	e := NewUnifiedEncoder(buffer, 1)
+	p := testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "binary",
+				seed: "something",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "binary",
+				seed: "otherthing",
+			},
+		}},
+	}
+
+	err := e.Encode(p)
+	c.Assert(err, IsNil)
+
+	c.Assert(buffer.String(), Equals, `diff --git a/binary b/binary
+index a459bc245bdbc45e1bca99e7fe61731da5c48da4..6879395eacf3cc7e5634064ccb617ac7aa62be7d 100644
+Binary files a/binary and b/binary differ
+`)
+}
+
+func (s *UnifiedEncoderTestSuite) TestEncode(c *C) {
+	for _, f := range fixtures {
+		c.Log("executing: ", f.desc)
+
+		buffer := bytes.NewBuffer(nil)
+		e := NewUnifiedEncoder(buffer, f.context)
+
+		err := e.Encode(f.patch)
+		c.Assert(err, IsNil)
+
+		c.Assert(buffer.String(), Equals, f.diff)
+	}
+}
+
+var oneChunkPatch Patch = testPatch{
+	message: "",
+	filePatches: []testFilePatch{{
+		from: &testFile{
+			mode: filemode.Regular,
+			path: "onechunk.txt",
+			seed: "A\nB\nC\nD\nE\nF\nG\nH\nI\nJ\nK\nL\nM\nN\nÑ\nO\nP\nQ\nR\nS\nT\nU\nV\nW\nX\nY\nZ",
+		},
+		to: &testFile{
+			mode: filemode.Regular,
+			path: "onechunk.txt",
+			seed: "B\nC\nD\nE\nF\nG\nI\nJ\nK\nL\nM\nN\nO\nP\nQ\nR\nS\nT\nV\nW\nX\nY\nZ",
+		},
+
+		chunks: []testChunk{{
+			content: "A\n",
+			op:      Delete,
+		}, {
+			content: "B\nC\nD\nE\nF\nG",
+			op:      Equal,
+		}, {
+			content: "H\n",
+			op:      Delete,
+		}, {
+			content: "I\nJ\nK\nL\nM\nN\n",
+			op:      Equal,
+		}, {
+			content: "Ñ\n",
+			op:      Delete,
+		}, {
+			content: "O\nP\nQ\nR\nS\nT\n",
+			op:      Equal,
+		}, {
+			content: "U\n",
+			op:      Delete,
+		}, {
+			content: "V\nW\nX\nY\nZ",
+			op:      Equal,
+		}},
+	}},
+}
+
+var oneChunkPatchInverted Patch = testPatch{
+	message: "",
+	filePatches: []testFilePatch{{
+		to: &testFile{
+			mode: filemode.Regular,
+			path: "onechunk.txt",
+			seed: "A\nB\nC\nD\nE\nF\nG\nH\nI\nJ\nK\nL\nM\nN\nÑ\nO\nP\nQ\nR\nS\nT\nU\nV\nW\nX\nY\nZ",
+		},
+		from: &testFile{
+			mode: filemode.Regular,
+			path: "onechunk.txt",
+			seed: "B\nC\nD\nE\nF\nG\nI\nJ\nK\nL\nM\nN\nO\nP\nQ\nR\nS\nT\nV\nW\nX\nY\nZ",
+		},
+
+		chunks: []testChunk{{
+			content: "A\n",
+			op:      Add,
+		}, {
+			content: "B\nC\nD\nE\nF\nG",
+			op:      Equal,
+		}, {
+			content: "H\n",
+			op:      Add,
+		}, {
+			content: "I\nJ\nK\nL\nM\nN\n",
+			op:      Equal,
+		}, {
+			content: "Ñ\n",
+			op:      Add,
+		}, {
+			content: "O\nP\nQ\nR\nS\nT\n",
+			op:      Equal,
+		}, {
+			content: "U\n",
+			op:      Add,
+		}, {
+			content: "V\nW\nX\nY\nZ",
+			op:      Equal,
+		}},
+	}},
+}
+
+var fixtures []*fixture = []*fixture{{
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Executable,
+				path: "test.txt",
+				seed: "test",
+			},
+			chunks: nil,
+		}},
+	},
+	desc:    "make executable",
+	context: 1,
+	diff: `diff --git a/test.txt b/test.txt
+old mode 100644
+new mode 100755
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "test1.txt",
+				seed: "test",
+			},
+			chunks: nil,
+		}},
+	},
+	desc:    "rename file",
+	context: 1,
+	diff: `diff --git a/test.txt b/test1.txt
+rename from test.txt
+rename to test1.txt
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "test1.txt",
+				seed: "test1",
+			},
+			chunks: []testChunk{{
+				content: "test",
+				op:      Delete,
+			}, {
+				content: "test1",
+				op:      Add,
+			}},
+		}},
+	},
+	desc:    "rename file with changes",
+	context: 1,
+	diff: `diff --git a/test.txt b/test1.txt
+rename from test.txt
+rename to test1.txt
+index 30d74d258442c7c65512eafab474568dd706c430..f079749c42ffdcc5f52ed2d3a6f15b09307e975e 100644
+--- a/test.txt
++++ b/test1.txt
+@@ -1 +1 @@
+-test
++test1
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Executable,
+				path: "test1.txt",
+				seed: "test",
+			},
+			chunks: nil,
+		}},
+	},
+	desc:    "rename with file mode change",
+	context: 1,
+	diff: `diff --git a/test.txt b/test1.txt
+old mode 100644
+new mode 100755
+rename from test.txt
+rename to test1.txt
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test2",
+			},
+
+			chunks: []testChunk{{
+				content: "test",
+				op:      Delete,
+			}, {
+				content: "test2",
+				op:      Add,
+			}},
+		}},
+	},
+
+	desc:    "one line change",
+	context: 1,
+	diff: `diff --git a/test.txt b/test.txt
+index 30d74d258442c7c65512eafab474568dd706c430..d606037cb232bfda7788a8322492312d55b2ae9d 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1 +1 @@
+-test
++test2
+`,
+}, {
+	patch: testPatch{
+		message: "this is the message\n",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test2",
+			},
+
+			chunks: []testChunk{{
+				content: "test",
+				op:      Delete,
+			}, {
+				content: "test2",
+				op:      Add,
+			}},
+		}},
+	},
+
+	desc:    "one line change with message",
+	context: 1,
+	diff: `this is the message
+diff --git a/test.txt b/test.txt
+index 30d74d258442c7c65512eafab474568dd706c430..d606037cb232bfda7788a8322492312d55b2ae9d 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1 +1 @@
+-test
++test2
+`,
+}, {
+	patch: testPatch{
+		message: "this is the message",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "test.txt",
+				seed: "test2",
+			},
+
+			chunks: []testChunk{{
+				content: "test",
+				op:      Delete,
+			}, {
+				content: "test2",
+				op:      Add,
+			}},
+		}},
+	},
+
+	desc:    "one line change with message and no end of line",
+	context: 1,
+	diff: `this is the message
+diff --git a/test.txt b/test.txt
+index 30d74d258442c7c65512eafab474568dd706c430..d606037cb232bfda7788a8322492312d55b2ae9d 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1 +1 @@
+-test
++test2
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: nil,
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "new.txt",
+				seed: "test\ntest2\test3",
+			},
+
+			chunks: []testChunk{{
+				content: "test\ntest2\ntest3",
+				op:      Add,
+			}},
+		}},
+	},
+
+	desc:    "new file",
+	context: 1,
+	diff: `diff --git a/new.txt b/new.txt
+new file mode 100644
+index 0000000000000000000000000000000000000000..65c8dd02a42273038658a22b1cb29c8d9457ca12
+--- /dev/null
++++ b/new.txt
+@@ -0,0 +1,3 @@
++test
++test2
++test3
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "old.txt",
+				seed: "test",
+			},
+			to: nil,
+
+			chunks: []testChunk{{
+				content: "test",
+				op:      Delete,
+			}},
+		}},
+	},
+
+	desc:    "delete file",
+	context: 1,
+	diff: `diff --git a/old.txt b/old.txt
+deleted file mode 100644
+index 30d74d258442c7c65512eafab474568dd706c430..0000000000000000000000000000000000000000
+--- a/old.txt
++++ /dev/null
+@@ -1 +0,0 @@
+-test
+`,
+}, {
+	patch:   oneChunkPatch,
+	desc:    "modified deleting lines file with context to 1",
+	context: 1,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index ab5eed5d4a2c33aeef67e0188ee79bed666bde6f..0adddcde4fd38042c354518351820eb06c417c82 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,2 +1 @@
+-A
+ B
+@@ -7,3 +6,2 @@ F
+ G
+-H
+ I
+@@ -14,3 +12,2 @@ M
+ N
+-Ñ
+ O
+@@ -21,3 +18,2 @@ S
+ T
+-U
+ V
+`,
+}, {
+	patch:   oneChunkPatch,
+	desc:    "modified deleting lines file with context to 2",
+	context: 2,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index ab5eed5d4a2c33aeef67e0188ee79bed666bde6f..0adddcde4fd38042c354518351820eb06c417c82 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,3 +1,2 @@
+-A
+ B
+ C
+@@ -6,5 +5,4 @@ E
+ F
+ G
+-H
+ I
+ J
+@@ -13,5 +11,4 @@ L
+ M
+ N
+-Ñ
+ O
+ P
+@@ -20,5 +17,4 @@ R
+ S
+ T
+-U
+ V
+ W
+`,
+}, {
+	patch: oneChunkPatch,
+
+	desc:    "modified deleting lines file with context to 3",
+	context: 3,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index ab5eed5d4a2c33aeef67e0188ee79bed666bde6f..0adddcde4fd38042c354518351820eb06c417c82 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,25 +1,21 @@
+-A
+ B
+ C
+ D
+ E
+ F
+ G
+-H
+ I
+ J
+ K
+ L
+ M
+ N
+-Ñ
+ O
+ P
+ Q
+ R
+ S
+ T
+-U
+ V
+ W
+ X
+`,
+}, {
+	patch:   oneChunkPatch,
+	desc:    "modified deleting lines file with context to 4",
+	context: 4,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index ab5eed5d4a2c33aeef67e0188ee79bed666bde6f..0adddcde4fd38042c354518351820eb06c417c82 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,26 +1,22 @@
+-A
+ B
+ C
+ D
+ E
+ F
+ G
+-H
+ I
+ J
+ K
+ L
+ M
+ N
+-Ñ
+ O
+ P
+ Q
+ R
+ S
+ T
+-U
+ V
+ W
+ X
+ Y
+`,
+}, {
+	patch:   oneChunkPatch,
+	desc:    "modified deleting lines file with context to 0",
+	context: 0,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index ab5eed5d4a2c33aeef67e0188ee79bed666bde6f..0adddcde4fd38042c354518351820eb06c417c82 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1 +0,0 @@
+-A
+@@ -8 +6,0 @@ G
+-H
+@@ -15 +12,0 @@ N
+-Ñ
+@@ -22 +18,0 @@ T
+-U
+`,
+}, {
+	patch:   oneChunkPatchInverted,
+	desc:    "modified adding lines file with context to 1",
+	context: 1,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index 0adddcde4fd38042c354518351820eb06c417c82..ab5eed5d4a2c33aeef67e0188ee79bed666bde6f 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1 +1,2 @@
++A
+ B
+@@ -6,2 +7,3 @@ F
+ G
++H
+ I
+@@ -12,2 +14,3 @@ M
+ N
++Ñ
+ O
+@@ -18,2 +21,3 @@ S
+ T
++U
+ V
+`,
+}, {
+	patch:   oneChunkPatchInverted,
+	desc:    "modified adding lines file with context to 2",
+	context: 2,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index 0adddcde4fd38042c354518351820eb06c417c82..ab5eed5d4a2c33aeef67e0188ee79bed666bde6f 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,2 +1,3 @@
++A
+ B
+ C
+@@ -5,4 +6,5 @@ E
+ F
+ G
++H
+ I
+ J
+@@ -11,4 +13,5 @@ L
+ M
+ N
++Ñ
+ O
+ P
+@@ -17,4 +20,5 @@ R
+ S
+ T
++U
+ V
+ W
+`,
+}, {
+	patch:   oneChunkPatchInverted,
+	desc:    "modified adding lines file with context to 3",
+	context: 3,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index 0adddcde4fd38042c354518351820eb06c417c82..ab5eed5d4a2c33aeef67e0188ee79bed666bde6f 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,21 +1,25 @@
++A
+ B
+ C
+ D
+ E
+ F
+ G
++H
+ I
+ J
+ K
+ L
+ M
+ N
++Ñ
+ O
+ P
+ Q
+ R
+ S
+ T
++U
+ V
+ W
+ X
+`,
+}, {
+	patch:   oneChunkPatchInverted,
+	desc:    "modified adding lines file with context to 4",
+	context: 4,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index 0adddcde4fd38042c354518351820eb06c417c82..ab5eed5d4a2c33aeef67e0188ee79bed666bde6f 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -1,22 +1,26 @@
++A
+ B
+ C
+ D
+ E
+ F
+ G
++H
+ I
+ J
+ K
+ L
+ M
+ N
++Ñ
+ O
+ P
+ Q
+ R
+ S
+ T
++U
+ V
+ W
+ X
+ Y
+`,
+}, {
+	patch:   oneChunkPatchInverted,
+	desc:    "modified adding lines file with context to 0",
+	context: 0,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index 0adddcde4fd38042c354518351820eb06c417c82..ab5eed5d4a2c33aeef67e0188ee79bed666bde6f 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -0,0 +1 @@
++A
+@@ -6,0 +8 @@ G
++H
+@@ -12,0 +15 @@ N
++Ñ
+@@ -18,0 +22 @@ T
++U
+`,
+}, {
+	patch: testPatch{
+		message: "",
+		filePatches: []testFilePatch{{
+			from: &testFile{
+				mode: filemode.Regular,
+				path: "onechunk.txt",
+				seed: "B\nC\nD\nE\nF\nG\nI\nJ\nK\nL\nM\nN\nO\nP\nQ\nR\nS\nT\nV\nW\nX\nY\nZ",
+			},
+			to: &testFile{
+				mode: filemode.Regular,
+				path: "onechunk.txt",
+				seed: "B\nC\nD\nE\nF\nG\nI\nJ\nK\nL\nM\nN\nO\nP\nQ\nR\nS\nT\nV\nW\nX\nY\n",
+			},
+
+			chunks: []testChunk{{
+				content: "B\nC\nD\nE\nF\nG\nI\nJ\nK\nL\nM\nN\nO\nP\nQ\nR\nS\nT\nV\nW\nX\nY\n",
+				op:      Equal,
+			}, {
+				content: "Z",
+				op:      Delete,
+			}},
+		}},
+	},
+	desc:    "remove last letter",
+	context: 0,
+	diff: `diff --git a/onechunk.txt b/onechunk.txt
+index 0adddcde4fd38042c354518351820eb06c417c82..553ae669c7a9303cf848fcc749a2569228ac5309 100644
+--- a/onechunk.txt
++++ b/onechunk.txt
+@@ -23 +22,0 @@ Y
+-Z
+`,
+}}
+
+type testPatch struct {
+	message     string
+	filePatches []testFilePatch
+}
+
+func (t testPatch) FilePatches() []FilePatch {
+	var result []FilePatch
+	for _, f := range t.filePatches {
+		result = append(result, f)
+	}
+
+	return result
+}
+
+func (t testPatch) Message() string {
+	return t.message
+}
+
+type testFilePatch struct {
+	from, to *testFile
+	chunks   []testChunk
+}
+
+func (t testFilePatch) IsBinary() bool {
+	return len(t.chunks) == 0
+}
+func (t testFilePatch) Files() (File, File) {
+	// Go is amazing
+	switch {
+	case t.from == nil && t.to == nil:
+		return nil, nil
+	case t.from == nil:
+		return nil, t.to
+	case t.to == nil:
+		return t.from, nil
+	}
+
+	return t.from, t.to
+}
+
+func (t testFilePatch) Chunks() []Chunk {
+	var result []Chunk
+	for _, c := range t.chunks {
+		result = append(result, c)
+	}
+	return result
+}
+
+type testFile struct {
+	path string
+	mode filemode.FileMode
+	seed string
+}
+
+func (t testFile) Hash() plumbing.Hash {
+	return plumbing.ComputeHash(plumbing.BlobObject, []byte(t.seed))
+}
+
+func (t testFile) Mode() filemode.FileMode {
+	return t.mode
+}
+
+func (t testFile) Path() string {
+	return t.path
+}
+
+type testChunk struct {
+	content string
+	op      Operation
+}
+
+func (t testChunk) Content() string {
+	return t.content
+}
+
+func (t testChunk) Type() Operation {
+	return t.op
+}
+
+type fixture struct {
+	desc    string
+	context int
+	diff    string
+	patch   Patch
+}