Merge "goexif: merge upstream and document process."

third_party/github.com/camlistore/goexif/README.camlistore

@@ -0,0 +1,82 @@
+Changing code under third_party/github.com/camlistore/goexif
+============================================================
+
+These instructions assume you have a github.com account.
+
+Sync github.com/rwcarlsen/goexif -> github.com/camlistore/goexif
+----------------------------------------------------------------
+1.  Issue a pull request at https://github.com/camlistore/goexif/pulls, set
+	the base fork to camlistore/goexif go1 branch, and the head fork as
+	rwcarlsen/goexif go1 branch.  Follow the normal github workflow until
+	someone on the camlistore project merges in the changes.
+
+Sync github.com/camlistore/goexif -> camlistore.org/third_party/github.com/camlistore/goexif
+--------------------------------------------------------------------------------------------
+1.  Once someone on the camlistore team merges in the latest from upstream,
+	checkout a local copy:
+
+	$ git clone https://github.com/camlistore/goexif 
+	$ cd goexif
+
+2.  Make a patch to apply to the camlistore.org copy.  You'll need to know the
+	git rev of github.com/camlistore/goexif that was last merged to
+	camlistore.org/third_party, for this example we'll use 030a4566:
+
+	# Create individual patches that have been applied upstream.
+	$ git format-patch -o /tmp/patches 030a4566
+	$ cd /path/to/camlistore.org/third_party/github.com/camlistore/goexif
+	# Create new branch to temporarily apply each upstream change.
+	$ git checkout -b patches_individual
+	# Apply patches.
+	$ git am --directory=third_party/github.com/camlistore/goexif /tmp/patches/*
+
+	# If something fails to apply try:
+	$ git apply <PATCH THAT FAILED> --reject
+	$ edit edit edit
+	$ git add <ANY FIXED FILES>
+	$ git am --resolved
+
+	# If it is a patch camlistore already had, because we created it and
+	# pushed it upstream, you can skip it with:
+	$ git am --skip
+
+	# Now create a new branch to squash all the changes into one. Keeping a
+	# record of upstream commits in the default commit message of a single
+	# commit.
+	$ git checkout -b patches_squashed master
+	$ git merge --squash patches_individual
+
+	# Verify no new files have been added that require import path updating:
+	$ cd /path/to/camlistore.org/third_party/
+	$ ./rewrite-imports.sh -l
+	# If any rewrites are required, run:
+	$ ./rewrite-imports.sh -w
+
+	# Now create a commit that will be sent for review.
+	$ git commit -v 
+
+	# Enter your commit message on the first line per usual.
+	# You should see summaries of all the changes merged in the commit
+	# message. Leave these, they will be useful next sync as we'll know what
+	# commits were sync'd. Send the change for review.
+	$ ./misc/review
+
+Sync camlistore.org/third_party/github.com/camlistore/goexif -> github.com/camlistore/goexif
+----------------------------------------------------------------------------------------------
+1.  TODO(wathiede): this should follow a similar process as 'Sync
+	github.com/camlistore/goexif ->
+	camlistore.org/third_party/github.com/camlistore/goexif'  Basically use
+	format-patch to generate a patch for each change we've made in
+	camlistore.org's repo and apply to a fork of github.com/camlistore/goexif.
+	Maybe skip the 'merge --squash' step, and keep each change in the log of
+	github.com/camlistore/goexif.
+
+Sync github.com/camlistore/goexif -> github.com/rwcarlsen/goexif 
+--------------------------------------------------------------------
+1.  This should follow the standard github pull-request workflow.  Issue a
+	pull request at https://github.com/request/goexif/pulls, set the base fork
+	to rwcarlsen/goexif go1 branch, and the head fork as camlistore/goexif go1
+	branch.
+
+2.  Address any feedback during review and rwcarlsen will merge changes to
+	github.com/rwcarlsen/goexif as appropriate.

third_party/github.com/camlistore/goexif/README.md

@@ -57,3 +57,4 @@ func main() {
 ```
 
 <!--golang-->
+[![githalytics.com alpha](https://cruel-carlota.pagodabox.com/5e166f74cdb82b999ccd84e3c4dc4348 "githalytics.com")](http://githalytics.com/rwcarlsen/goexif)

third_party/github.com/camlistore/goexif/exif/exif.go

@@ -58,15 +58,61 @@ type Exif struct {
 
 // Decode parses EXIF-encoded data from r and returns a queryable Exif object.
 func Decode(r io.Reader) (*Exif, error) {
-	sec, err := newAppSec(0xE1, r)
+	// EXIF data in JPEG is stored in the APP1 marker. EXIF data uses the TIFF
+	// format to store data.
+	// If we're parsing a TIFF image, we don't need to strip away any data.
+	// If we're parsing a JPEG image, we need to strip away the JPEG APP1
+	// marker and also the EXIF header.
+	header := make([]byte, 4)
+	n, err := r.Read(header)
+	if n < len(header) {
+		return nil, errors.New("exif: short read on header")
+	}
 	if err != nil {
 		return nil, err
 	}
-	er, err := sec.exifReader()
-	if err != nil {
-		return nil, err
+
+	var isTiff bool
+	switch string(header) {
+	case "II*\x00":
+		// TIFF - Little endian (Intel)
+		isTiff = true
+	case "MM\x00*":
+		// TIFF - Big endian (Motorola)
+		isTiff = true
+	default:
+		// Not TIFF, assume JPEG
 	}
-	tif, err := tiff.Decode(er)
+
+	// Put the header bytes back into the reader.
+	r = io.MultiReader(bytes.NewReader(header), r)
+	var (
+		er  *bytes.Reader
+		tif *tiff.Tiff
+	)
+
+	if isTiff {
+		// Functions below need the IFDs from the TIFF data to be stored in a
+		// *bytes.Reader.  We use TeeReader to get a copy of the bytes as a
+		// side-effect of tiff.Decode() doing its work.
+		b := &bytes.Buffer{}
+		tr := io.TeeReader(r, b)
+		tif, err = tiff.Decode(tr)
+		er = bytes.NewReader(b.Bytes())
+	} else {
+		// Strip away JPEG APP1 header.
+		sec, err := newAppSec(0xE1, r)
+		if err != nil {
+			return nil, err
+		}
+		// Strip away EXIF header.
+		er, err = sec.exifReader()
+		if err != nil {
+			return nil, err
+		}
+		tif, err = tiff.Decode(er)
+	}
+
 	if err != nil {
 		return nil, errors.New("exif: decode failed: " + err.Error())
 	}

third_party/github.com/camlistore/goexif/exif/exif_test.go

@@ -19,7 +19,7 @@ func TestDecode(t *testing.T) {
 		t.Fatal(err)
 	}
 	if x == nil {
-		t.Fatal("No error and yet %v was not decoded\n", name)
+		t.Fatalf("No error and yet %v was not decoded\n", name)
 	}
 
 	val, err := x.Get("Model")

third_party/github.com/camlistore/goexif/tiff/tag.go

@@ -186,16 +186,16 @@ func (t *Tag) convertVals() {
 			t.ratVals[i] = []int64{int64(n), int64(d)}
 		}
 	case 11: // float32
+		t.floatVals = make([]float64, int(t.Ncomp))
 		for i := 0; i < int(t.Ncomp); i++ {
-			t.floatVals = make([]float64, int(t.Ncomp))
 			var v float32
 			err := binary.Read(r, t.order, &v)
 			panicOn(err)
 			t.floatVals[i] = float64(v)
 		}
 	case 12: // float64 (double)
+		t.floatVals = make([]float64, int(t.Ncomp))
 		for i := 0; i < int(t.Ncomp); i++ {
-			t.floatVals = make([]float64, int(t.Ncomp))
 			var u float64
 			err := binary.Read(r, t.order, &u)
 			panicOn(err)