Adsk Contrib - Add Support for SMPTE ST 2036-1 compliant CLF files (#2265)

* Adding reading and writing support for SMPTE ST 2036-1 compliant CLF files.

- Added "Id" element support per the spec.

- Extended the CTFVersion class to handle non-numeric formats per the spec (which uses xmlns as the version)

- CLF xml parser now strips the namespaces from the elements by default. This makes it possible to parse files with simple name spaces but complex name-spaced clf files may still fail. There is an internal switch to turn on/off the name space stripping. This way elements which need to retain the name spaces (such as the Info element) can still get the un-stripped names.

- Extended the Input and Output Descriptor collection to hold multiple entries (similar to Description field)

- CLF writer now writes the SMPTE xmlns version as well as the CompCLFVersion attribute. The resulting files can be read both by the Academy CLF parsers and SMPTE CLF parsers.

- Generated cache hash IDs are now in the 8-4-4-4-12 UUID format to help complying with SMPTE id requirements

- ociomakeclf tool now takes "--generateid" switch to for inserting newly added "Id element" into the target clf file.

TODO:

- Description and Descriptor elements need to collect the language attribute.

- non-default namespace attributes (e.g. xmlns:foo) needs to be collected as root level attributes.

- Those two TODO items need some re-factoring in the data collection code.

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>

* - Per the code review, exposing the newly added constant METADATA_ID_ELEMENT in python too.

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>

* - re-worked some part of the CLF parser and the CTFReaderTransform class to be able to collect richer metadata.
- Now collecting the language attribute of the Description, input and output descriptor elements.
- Also collecting the non-default xmlns attributes at the root level.
- Updated the tests accordingly.
- Replaced clf/pre-smpte_only/matrix_example.clf with clf/matrix_example_utf8.clf in some for some Reference tests.
- Added format information to the ociomakeclf tool's help text.

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>

* - nmake the compilers happy.

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>

* - make the compilers happy pt2

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>

* - make the compilers happy pt3
(we need to make Windows compiler settings as picky as other platforms)

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>

---------

Signed-off-by: cuneyt.ozdas <cuneyt.ozdas@autodesk.com>
Co-authored-by: Doug Walker <doug.walker@autodesk.com>

Author: cozdas

include/OpenColorIO/OpenColorTypes.h

@@ -977,6 +977,13 @@ extern OCIOEXPORT const char * METADATA_NAME;
  */
 extern OCIOEXPORT const char * METADATA_ID;
 
+/**
+ * An ID when stored as an XML element rather than as an attribute. This is the
+ * preferred mechanism in the SMPTE ST 2036-1 version of the CLF format. If
+ * present, it is only available from the top-level FormatMetadata.
+ */
+ extern OCIOEXPORT const char * METADATA_ID_ELEMENT;
+
 /*!rst::
 Caches
 ******

src/OpenColorIO/HashUtils.cpp

@@ -2,6 +2,7 @@
 // Copyright Contributors to the OpenColorIO Project.
 
 #include <sstream>
+#include <iomanip>
 
 #include <OpenColorIO/OpenColorIO.h>
 
@@ -25,4 +26,27 @@ std::string CacheIDHash(const char * array, std::size_t size)
     return oss.str();
 }
 
+std::string CacheIDHashUUID(const char * array, std::size_t size)
+{
+    XXH128_hash_t hash = XXH3_128bits(array, size);
+
+    // Make sure that we have full, zero-padded 32 chars.
+    std::stringstream oss;
+    oss << std::hex << std::setfill('0');
+    oss << std::setw(16) << hash.high64;
+    oss << std::setw(16) << hash.low64;
+
+    // Format into 8-4-4-4-12 form.
+    std::string hex = oss.str();    
+    std::string uuid =
+        hex.substr(0, 8)  + "-" +
+        hex.substr(8, 4)  + "-" +
+        hex.substr(12, 4) + "-" +
+        hex.substr(16, 4) + "-" +
+        hex.substr(20, 12);
+    
+    return uuid;
+}
+
+
 } // namespace OCIO_NAMESPACE

src/OpenColorIO/HashUtils.h

@@ -14,6 +14,10 @@ namespace OCIO_NAMESPACE
 
 std::string CacheIDHash(const char * array, std::size_t size);
 
+// Generates 128 bit UUID in the form of 8-4-4-4-12 using the hash of the passed
+// string.
+std::string CacheIDHashUUID(const char * array, std::size_t size);
+
 } // namespace OCIO_NAMESPACE
 
 #endif

src/OpenColorIO/Processor.cpp

@@ -330,15 +330,9 @@ const char * Processor::Impl::getCacheID() const
 
     if(!m_cacheID.empty()) return m_cacheID.c_str();
 
-    if(m_ops.empty())
-    {
-        m_cacheID = "<NOOP>";
-    }
-    else
-    {
-        const std::string fullstr = m_ops.getCacheID();
-        m_cacheID = CacheIDHash(fullstr.c_str(), fullstr.size());
-    }
+    // Note: empty ops vector will also create a UUID.
+    const std::string fullstr = m_ops.getCacheID();
+    m_cacheID = CacheIDHashUUID(fullstr.c_str(), fullstr.size());
 
     return m_cacheID.c_str();
 }