Update XMP metadata

Bug: b/252835416
Change-Id: Iced2c5bf6b5e2dfd7139c43fad6b0bca0d1b2d1c
Test: build, print generated xmp
diff --git a/libs/jpegrecoverymap/recoverymaputils.cpp b/libs/jpegrecoverymap/recoverymaputils.cpp
index fe46cba..537f86f 100644
--- a/libs/jpegrecoverymap/recoverymaputils.cpp
+++ b/libs/jpegrecoverymap/recoverymaputils.cpp
@@ -17,19 +17,29 @@
 #include <jpegrecoverymap/recoverymaputils.h>
 #include <jpegrecoverymap/recoverymap.h>
 #include <image_io/xml/xml_reader.h>
+#include <image_io/xml/xml_writer.h>
 #include <image_io/base/message_handler.h>
 #include <image_io/xml/xml_element_rules.h>
 #include <image_io/xml/xml_handler.h>
 #include <image_io/xml/xml_rule.h>
 
-#include <string>
-#include <sstream>
-
 using namespace photos_editing_formats::image_io;
 using namespace std;
 
 namespace android::recoverymap {
 
+/*
+ * Helper function used for generating XMP metadata.
+ *
+ * @param prefix The prefix part of the name.
+ * @param suffix The suffix part of the name.
+ * @return A name of the form "prefix:suffix".
+ */
+string Name(const string &prefix, const string &suffix) {
+  std::stringstream ss;
+  ss << prefix << ":" << suffix;
+  return ss.str();
+}
 
 // Extremely simple XML Handler - just searches for interesting elements
 class XMPXmlHandler : public XmlHandler {
@@ -104,6 +114,36 @@
 
 const string XMPXmlHandler::rangeScalingFactorName = "GContainer:rangeScalingFactor";
 
+const string kContainerPrefix   = "GContainer";
+const string kContainerUri      = "http://ns.google.com/photos/1.0/container/";
+const string kRecoveryMapUri    = "http://ns.google.com/photos/1.0/recoverymap/";
+const string kItemPrefix        = "Item";
+const string kRecoveryMap       = "RecoveryMap";
+const string kDirectory         = "Directory";
+const string kImageJpeg         = "image/jpeg";
+const string kItem              = "Item";
+const string kLength            = "Length";
+const string kMime              = "Mime";
+const string kPrimary           = "Primary";
+const string kSemantic          = "Semantic";
+const string kVersion           = "Version";
+const string kHdr10Metadata     = "HDR10Metadata";
+const string kSt2086Metadata    = "ST2086Metadata";
+const string kSt2086Coordinate  = "ST2086Coordinate";
+const string kSt2086CoordinateX = "ST2086CoordinateX";
+const string kSt2086CoordinateY = "ST2086CoordinateY";
+const string kSt2086Primary     = "ST2086Primary";
+const int kSt2086PrimaryRed     = 0;
+const int kSt2086PrimaryGreen   = 1;
+const int kSt2086PrimaryBlue    = 2;
+const int kSt2086PrimaryWhite   = 3;
+const int kGContainerVersion    = 1;
+
+const string kConDir            = Name(kContainerPrefix, kDirectory);
+const string kContainerItem     = Name(kContainerPrefix, kItem);
+const string kItemLength        = Name(kItemPrefix, kLength);
+const string kItemMime          = Name(kItemPrefix, kMime);
+const string kItemSemantic      = Name(kItemPrefix, kSemantic);
 
 bool getMetadataFromXMP(uint8_t* xmp_data, size_t xmp_size, jpegr_metadata* metadata) {
     string nameSpace = "http://ns.adobe.com/xap/1.0/\0";
@@ -150,4 +190,96 @@
     return true;
 }
 
+string generateXmp(int secondary_image_length, jpegr_metadata& metadata) {
+  const vector<string> kConDirSeq({kConDir, string("rdf:Seq")});
+  const vector<string> kLiItem({string("rdf:li"), kContainerItem});
+
+  std::stringstream ss;
+  photos_editing_formats::image_io::XmlWriter writer(ss);
+  writer.StartWritingElement("x:xmpmeta");
+  writer.WriteXmlns("x", "adobe:ns:meta/");
+  writer.WriteAttributeNameAndValue("x:xmptk", "Adobe XMP Core 5.1.2");
+  writer.StartWritingElement("rdf:RDF");
+  writer.WriteXmlns("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
+  writer.StartWritingElement("rdf:Description");
+  writer.WriteXmlns(kContainerPrefix, kContainerUri);
+  writer.WriteXmlns(kRecoveryMap, kRecoveryMapUri);
+  writer.WriteElementAndContent(Name(kContainerPrefix, kVersion), kGContainerVersion);
+  writer.StartWritingElements(kConDirSeq);
+  size_t item_depth = writer.StartWritingElements(kLiItem);
+  writer.WriteAttributeNameAndValue(kItemSemantic, kPrimary);
+  writer.WriteAttributeNameAndValue(kItemMime, kImageJpeg);
+  writer.WriteAttributeNameAndValue(Name(kRecoveryMap, kVersion), metadata.version);
+  writer.WriteAttributeNameAndValue(
+      Name(kRecoveryMap, "RangeScalingFactor"), metadata.rangeScalingFactor);
+  writer.WriteAttributeNameAndValue(
+      Name(kRecoveryMap, "TransferFunction"), metadata.transferFunction);
+  if (metadata.transferFunction == JPEGR_TF_PQ) {
+    writer.StartWritingElement(Name(kRecoveryMap, kHdr10Metadata));
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, "HDR10MaxFALL"), metadata.hdr10Metadata.maxFALL);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, "HDR10MaxCLL"), metadata.hdr10Metadata.maxCLL);
+    writer.StartWritingElement(Name(kRecoveryMap, kSt2086Metadata));
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, "ST2086MaxLuminance"),
+        metadata.hdr10Metadata.st2086Metadata.maxLuminance);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, "ST2086MinLuminance"),
+        metadata.hdr10Metadata.st2086Metadata.minLuminance);
+
+    // red
+    writer.StartWritingElement(Name(kRecoveryMap, kSt2086Coordinate));
+    writer.WriteAttributeNameAndValue(Name(kRecoveryMap, kSt2086Primary), kSt2086PrimaryRed);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateX),
+        metadata.hdr10Metadata.st2086Metadata.redPrimary.x);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateY),
+        metadata.hdr10Metadata.st2086Metadata.redPrimary.y);
+    writer.FinishWritingElement();
+
+    // green
+    writer.StartWritingElement(Name(kRecoveryMap, kSt2086Coordinate));
+    writer.WriteAttributeNameAndValue(Name(kRecoveryMap, kSt2086Primary), kSt2086PrimaryGreen);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateX),
+        metadata.hdr10Metadata.st2086Metadata.greenPrimary.x);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateY),
+        metadata.hdr10Metadata.st2086Metadata.greenPrimary.y);
+    writer.FinishWritingElement();
+
+    // blue
+    writer.StartWritingElement(Name(kRecoveryMap, kSt2086Coordinate));
+    writer.WriteAttributeNameAndValue(Name(kRecoveryMap, kSt2086Primary), kSt2086PrimaryBlue);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateX),
+        metadata.hdr10Metadata.st2086Metadata.bluePrimary.x);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateY),
+        metadata.hdr10Metadata.st2086Metadata.bluePrimary.y);
+    writer.FinishWritingElement();
+
+    // white
+    writer.StartWritingElement(Name(kRecoveryMap, kSt2086Coordinate));
+    writer.WriteAttributeNameAndValue(Name(kRecoveryMap, kSt2086Primary), kSt2086PrimaryWhite);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateX),
+        metadata.hdr10Metadata.st2086Metadata.whitePoint.x);
+    writer.WriteAttributeNameAndValue(
+        Name(kRecoveryMap, kSt2086CoordinateY),
+        metadata.hdr10Metadata.st2086Metadata.whitePoint.y);
+    writer.FinishWritingElement();
+  }
+  writer.FinishWritingElementsToDepth(item_depth);
+  writer.StartWritingElements(kLiItem);
+  writer.WriteAttributeNameAndValue(kItemSemantic, kRecoveryMap);
+  writer.WriteAttributeNameAndValue(kItemMime, kImageJpeg);
+  writer.WriteAttributeNameAndValue(kItemLength, secondary_image_length);
+  writer.FinishWriting();
+
+  return ss.str();
+}
+
 } // namespace android::recoverymap
\ No newline at end of file