Add JSON read support.

source/MaterialXFormat/JSONIo.cpp

@@ -18,14 +18,15 @@
 MATERIALX_NAMESPACE_BEGIN
 
 const string JSON_EXTENSION = "json";
+const string JSON_MIME_TYPE = "application/mtlx+json";
 using json = nlohmann::json;
 
 namespace
 {
-
+ // Writing utility
  void elementToJSON(ConstElementPtr elem, json& jsonObject, const JSONWriteOptions* writeOptions)
  {
- ElementPredicate elementPredicate = nullptr;
+ ElementPredicate elementPredicate;
  bool addDefinitionInformation = true;
  bool storeLayoutInformation = true;
  bool addNodeGraphChildren = true;
@@ -101,6 +102,139 @@ namespace
  // Add new element to parent
  jsonObject[elem->getName()] = jsonElem;
  }
+
+ // Reading utilities
+ void elementFromJSON(const json& node, ElementPtr elem, const JSONReadOptions* readOptions,
+ const string& indent)
+ {
+ if (node.is_object()) 
+ {
+ for (const auto& entry : node.items()) 
+ {
+ const std::string& key = entry.key();
+ const json& value = entry.value();
+
+ // Handle attributes
+ if (value.is_string())
+ {
+ string attrName = key;
+ if (attrName.at(0) == '@')
+ attrName.erase(0, 1);
+
+ const StringSet skipKeys = { "name", "category" };
+ if (!skipKeys.count(key))
+ {
+ //std::cout << indent << "Set Attribute: " << attrName << " to: " << value << std::endl;
+ elem->setAttribute(attrName, string(value));
+ }
+ }
+ else
+ {
+ string name = string(key);
+
+ // Check for duplicate elements.
+ ConstElementPtr previous = elem->getChild(name);
+ if (!previous)
+ {
+ // Create a new element of the proper category
+ string category = EMPTY_STRING;
+ for (const auto& e : value.items())
+ {
+ const std::string& k = e.key();
+ if (k == "@category")
+ {
+ category = string(e.value());
+ }
+ }
+
+ if (!category.empty())
+ {
+ //std::cout << indent << "Create Element <" << category << "> Name: " << name << std::endl;
+ ElementPtr child = elem->addChildOfCategory(category, name);
+ elementFromJSON(value, child, readOptions, indent + string(" "));
+ }
+ }
+ }
+ }
+ }
+ }
+
+ void documentFromJSON(DocumentPtr doc,
+ const json& jsonDoc,
+ const JSONReadOptions* readOptions = nullptr)
+ {
+ const string indent = " ";
+ //if (jsonDoc.is_object())
+ {
+ // Go through all top level items
+ for (const auto& entry: jsonDoc.items())
+ {
+ // Handle top level attrs here.
+
+ const string& key = entry.key();
+ const json& value = entry.value();
+ if (value.is_string())
+ {
+ string attrName = key;
+ if (attrName.at(0) == '@')
+ attrName.erase(0, 1);
+ //std::cout << indent << "Set Doc Attribute: " << attrName << " to: " << value << std::endl;
+ doc->setAttribute(attrName, string(value));
+ }
+ else
+ {
+ elementFromJSON(value, doc, readOptions, indent);
+ }
+ }
+ elementFromJSON(jsonDoc, doc, readOptions, indent);
+ if (!readOptions || readOptions->upgradeVersion)
+ {
+ doc->upgradeVersion();
+ }
+ }
+ }
+}
+
+//
+// Reading
+//
+void readFromJSONString(DocumentPtr doc, const string& buffer, const JSONReadOptions* readOptions)
+{
+ std::stringstream inputStream;
+ inputStream << buffer;
+
+ readFromJSONStream(doc, inputStream, readOptions);
+}
+
+void readFromJSONStream(DocumentPtr doc, std::istream& stream, const JSONReadOptions* readOptions)
+{
+ json jsonDoc; 
+ try
+ {
+ jsonDoc = json::parse(stream);
+ }
+ catch (const json::parse_error& e) {
+ std::cerr << "JSON parsing error: " << e.what() << std::endl;
+ }
+
+ documentFromJSON(doc, jsonDoc, readOptions);
+}
+
+void readFromJSONFile(DocumentPtr doc,
+ FilePath filename,
+ FileSearchPath searchPath,
+ const JSONReadOptions* readOptions)
+{
+ searchPath.append(getEnvironmentPath());
+ filename = searchPath.find(filename);
+
+ std::ifstream inputFile;
+ inputFile.open(filename.asString());
+ if (!inputFile.is_open()) {
+ throw std::runtime_error(string("Unable to open JSON file:") + filename.asString());
+ }
+
+ readFromJSONStream(doc, inputFile, readOptions);
 }
 
 //
@@ -110,6 +244,8 @@ namespace
 void writeToJSONStream(DocumentPtr doc, std::ostream& stream, const JSONWriteOptions* writeOptions)
 {
  json materialXRoot;
+ materialXRoot["mimtype"] = "application/mtlx+json";
+
  json documentRoot = json::object();
 
  for (const string& attrName : doc->getAttributeNames())

source/MaterialXFormat/JSONIo.h

@@ -18,11 +18,26 @@
 
 MATERIALX_NAMESPACE_BEGIN
 
-class XmlReadOptions;
+class JSONReadOptions;
 
 extern MX_FORMAT_API const string JSON_EXTENSION;
+extern MX_FORMAT_API const string JSON_MIME_TYPE;
 
+/// @class JSONReadOptions
+/// A set of options for controlling the behavior of JSON read functions.
+class MX_FORMAT_API JSONReadOptions
+{
+public:
+ JSONReadOptions() {};
+ ~JSONReadOptions() { }
+
+ /// If true, then documents from earlier versions of MaterialX will be upgraded
+ /// to the current version. Defaults to true.
+ bool upgradeVersion = true;
+};
 
+/// @class JSONWriteOptions
+/// A set of options for controlling the behavior of JSON write functions.
 class MX_FORMAT_API JSONWriteOptions
 {
 public:
@@ -46,14 +61,74 @@ class MX_FORMAT_API JSONWriteOptions
  unsigned int indent = 4;
 };
 
-/// @name Write Functions
+/// @name Read Functions
 /// @{
 
+/// Read a Document as JSON from the given character buffer.
+/// @param doc The Document into which data is read.
+/// @param buffer The string buffer from which data is read.
+/// @param readOptions An optional pointer to an JSONReadOptions object.
+/// If provided, then the given options will affect the behavior of the
+/// read function. Defaults to a null pointer.
+/// @throws ExceptionParseError if the document cannot be parsed.
+MX_FORMAT_API void readFromJSONString(DocumentPtr doc, const string& buffer, const JSONReadOptions* readOptions = nullptr);
+
+/// Read a Document as JSON from the given input stream.
+/// @param doc The Document into which data is read.
+/// @param stream The input stream from which data is read.
+/// @param readOptions An optional pointer to an JSONReadOptions object.
+/// If provided, then the given options will affect the behavior of the
+/// read function. Defaults to a null pointer.
+/// @throws ExceptionParseError if the document cannot be parsed.
+MX_FORMAT_API void readFromJSONStream(DocumentPtr doc, std::istream& stream, const JSONReadOptions* readOptions = nullptr);
+
+/// Read a Document as JSON from the given filename.
+/// @param doc The Document into which data is read.
+/// @param filename The filename from which data is read. This argument can
+/// be supplied either as a FilePath or a standard string.
+/// @param readOptions An optional pointer to an JSONReadOptions object.
+/// If provided, then the given options will affect the behavior of the read
+/// function. Defaults to a null pointer.
+/// @throws ExceptionParseError if the document cannot be parsed.
+/// @throws ExceptionFileMissing if the file cannot be opened.
+MX_FORMAT_API void readFromJSONFile(DocumentPtr doc,
+ FilePath filename,
+ FileSearchPath searchPath = FileSearchPath(),
+ const JSONReadOptions* readOptions = nullptr);
+
+/// @}
+/// @name Write Functions
+
+/// Write a Document as JSON to the given filename.
+/// @param doc The Document to be written.
+/// @param filename The filename to which data is written. This argument can
+/// be supplied either as a FilePath or a standard string.
+/// @param writeOptions An optional pointer to an JSONWriteOptions object.
+/// If provided, then the given options will affect the behavior of the
+/// write function. Defaults to a null pointer.
 MX_FORMAT_API void writeToJSONFile(DocumentPtr doc, const FilePath& filename, const JSONWriteOptions* writeOptions = nullptr);
+
+/// Write a Document as JSON to a new string, returned by value.
+/// @param doc The Document to be written.
+/// @param writeOptions An optional pointer to an JSONWriteOptions object.
+/// If provided, then the given options will affect the behavior of the
+/// write function. Defaults to a null pointer.
+/// @return The output string, returned by value
 MX_FORMAT_API string writeToJSONString(DocumentPtr doc, const JSONWriteOptions* writeOptions = nullptr);
 
+/// Write a Document as JSON to the given output stream.
+/// @param doc The Document to be written.
+/// @param stream The output stream to which data is written
+/// @param writeOptions An optional pointer to an JSONWriteOptions object.
+/// If provided, then the given options will affect the behavior of the
+/// write function. Defaults to a null pointer.
+MX_FORMAT_API void writeToJSONStream(DocumentPtr doc, std::ostream& stream, const JSONWriteOptions* writeOptions);
+
 /// @}
 
+/// @}
+
+
 MATERIALX_NAMESPACE_END
 
 #endif

source/MaterialXGraphEditor/Graph.cpp

@@ -158,6 +158,7 @@ mx::DocumentPtr Graph::loadDocument(mx::FilePath filename)
  try
  {
  readFromXmlFile(doc, resolvedFilename, searchPath, options);
+ readFromJSONFile(doc, resolvedFilename);
  }
  catch (mx::Exception& e)
  {
@@ -176,7 +177,14 @@ mx::DocumentPtr Graph::loadDocument(mx::FilePath filename)
  {
  if (!filename.isEmpty())
  {
- mx::readFromXmlFile(doc, filename, _searchPath, &readOptions);
+ if (filename.getExtension() == "json")
+ {
+ mx::readFromJSONFile(doc, filename, _searchPath);
+ }
+ else
+ {
+ mx::readFromXmlFile(doc, filename, _searchPath, &readOptions);
+ }
  doc->importLibrary(_stdLib);
  std::string message;
  if (!doc->validate(&message))