Difference between revisions of "DOM code generator"

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(copy in Andy's text from word doc)
 
(editing first pass, mostly formatting, plus some questions)
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COLLADA Code Generator
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'''Summary:'''  The '''COLLADA Code Generator''' is/does ''((ANDY: fill in summary))''.
  
==dom generated types==
+
==DOM generated types==
  
The DOM has it’s basic types defined in daeTypes.h . There are mappings from XML Schema basic types to DOM types in daeDomTypes.h
+
The DOM's basic types are defined in '''daeTypes.h'''. There are mappings from XML Schema basic types to DOM types in '''daeDomTypes.h'''.
  
 
Any other new types defined in the schema document generate new atomic types or add name bindings to existing atomic types in the DOM.
 
Any other new types defined in the schema document generate new atomic types or add name bindings to existing atomic types in the DOM.
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All types defined in the schema are either restrictions, extensions, unions, or lists of existing types.
 
All types defined in the schema are either restrictions, extensions, unions, or lists of existing types.
  
The dom generates types in domTypes.h
+
The DOM generates types in '''domTypes.h'''.
  
The format is “typedef base_type_name domNew_type_name” for most type declarations.
+
The format for most type declarations is:
 +
typedef ''base_type_name'' ''domNew_type_name''
  
“typedef daeTArray< base_type_name > domNew_type_name” is used for list types.
+
The format for list types is:
 +
typedef daeTArray< ''base_type_name'' > ''domNew_type_name''
  
Enum types take the form of “enum domNew_type_name”. Each enum value is then created as “NEW_TYPE_NAME_Enum”.
+
Enum types take the form of “enum dom''New_type_name''”. Each enum value is then created as “''NEW_TYPE_NAME''_Enum”.
  
Union types are only supported for unions of enums. A new enum is generated for that union type containing the symbols and values of all enums contained in the union.
+
Union types are supported only for unions of enums. A new enum is generated for that union type containing the symbols and values of all enums contained in the union.
  
These types are registered in the registerDomTypes function found in domTypes.cpp. For all types except enums code is generated that looks like  
+
These types are registered in the '''registerDomTypes''' function found in '''domTypes.cpp'''. For all types except enums code is generated that looks like  
type = daeAtomicType::get("base_type_name");
+
type = daeAtomicType::get("base_type_name");
 
if ( type == NULL ) { //register as a raw type
 
if ( type == NULL ) { //register as a raw type
 
type = new daeRawRefType;
 
type = new daeRawRefType;
Line 29: Line 31:
 
type->_nameBindings.append("new_type_name ");
 
type->_nameBindings.append("new_type_name ");
 
}
 
}
This code searches for a type for the base_type_name. If it finds one it adds new_type_name as a name binding for that type. If the base type does not exist then a new rawRefType is created.
+
This code searches for a type for the '''base_type_name'''. If it finds one, it adds '''new_type_name''' as a name binding for that type. If the base type does not exist then a new '''rawRefType''' is created.
  
Enums always get a new type generated. The two arrays _strings and _values get populated with the enum values.
+
Enums always get a new type generated. The two arrays '''_strings''' and '''_values''' are populated with the enum values.
  
In the schema, if an enumeration has an <xs:annotation> with an <xs:appinfo> value=value the enum created will have a value value.
+
In the schema, if an enumeration has an '''<xs:annotation>''' with an '''<xs:appinfo> value=''value''''', the enum created will have a '''value''' value.
  
==dom generated classes==
+
==DOM-generated classes==
 
===Interface===
 
===Interface===
  
Each <xs:element> <xs:group> and <xs:complexType> generates a new daeElement subclass name domElement_name.
+
Each '''<xs:element> <xs:group>''' and '''<xs:complexType>''' generates a new '''daeElement''' subclass name '''dom''Element_name'''''.
  
Each attribute and child element and a value (if it has one) gets its data storage and accessor and mutators. Array types and URIs get returned by reference. All other types are returned by value.
+
Each attribute and child element and a value (if it has one) gets its data storage and accessor and mutators. Array types and URIs are returned by reference. All other types are returned by value.
  
If an element has an xs:choice content model group and more than a single child element it will have a _contents, _contentsOrder, and _CMData arrays to store the data needed to represent the ordering of children in the content model.
+
If an element has an '''xs:choice''' content model group and more than a single child element, it will have '''_contents''', '''_contentsOrder''', and '''_CMData''' arrays to store the data needed to represent the ordering of children in the content model.
  
An xs:complexType generates two classes. The first is the class description/interface. The second is a daeElement subclass that inherits from both daeElement and the new class interface.
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An '''xs:complexType''' generates two classes:
 +
* The class description/interface.
 +
* A '''daeElement''' subclass that inherits from both '''daeElement''' and the new class interface.
  
Any class defined in XMLSchema global scope (not defined as a child of another element) generates a new daeElement subclass. This new element, if the type attribute is a complex type, also inherits from the complex type interface and daeElement.
+
Any class defined in XMLSchema global scope (not defined as a child of another element) generates a new '''daeElement''' subclass. This new element, if the type attribute is a complex type, also inherits from the complex type interface and '''daeElement'''.
  
An element that is part of a substitution group inherits from the element it is substitutable for. Then the DOM uses polymorphism and stores a pointer to the base class which could be an object of any of the substitutable classes.
+
An element that is part of a substitution group inherits from the element it is substitutable for. Then the DOM uses polymorphism and stores a pointer to the base class, which could be an object of any of the substitutable classes.
  
The code generator does allow for schema type inheritance by either extension or restriction. In either case the new class inherits from the base class. Restriction is handled with the DOM meta information since C++ can only do inheritance by extension. The current (COLLADA 1.4.1) schema does not take advantage of this feature.
+
The code generator allows for schema type inheritance by either extension or restriction. In either case the new class inherits from the base class. Restriction is handled with the DOM meta information since C++ can do inheritance only by extension. The current (COLLADA 1.4.1) schema does not take advantage of this feature.
  
 
The code generator allows for scoped type definitions. This would happen when a simple type is created anonymously in the schema document instead of creating a global simple type and referencing it. The current (COLLADA 1.4.1) schema does not take advantage of this feature.
 
The code generator allows for scoped type definitions. This would happen when a simple type is created anonymously in the schema document instead of creating a global simple type and referencing it. The current (COLLADA 1.4.1) schema does not take advantage of this feature.
  
When generating mutators for string data attributes or values, the generator creates code *(daeStringRef*)&attrAttribute_name = atAttribute_name that lets the DOM create memory to store it’s string data.
+
When generating mutators for string data attributes or values, the generator creates code:
 +
*(daeStringRef*)&attrAttribute_name = atAttribute_name  
 +
which lets the DOM create memory to store its string data.
  
The xmlns attribute is specially created only for elements that have an <xs:annotation> <xs:appinfo> that contains “enable-xmlns”
+
The '''xmlns''' attribute is specially created only for elements that have an '''<xs:annotation> <xs:appinfo>''' that contains '''enable-xmlns'''.
  
 
===Meta generation===
 
===Meta generation===
  
Each element that gets generated has a function registerElement. RegisterElement is the function that gets called to create the meta information that describes the new element.
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Each element that is generated has a function ''registerElement''. This is the function that is called to create the meta information that describes the new element.
  
Every element’s _Meta descriptor has a name and a pointer to the element’s creation function create(daeInt bytes).
+
Every element’s '''_Meta''' descriptor has a name and a pointer to the element’s creation function '''create(daeInt bytes)'''.
  
If the new element is created from an <xs:group> then the meta will be tagged as transparent. Transparent means that the IOplugin will not create an XML tag or any attributes for this element when it gets saved out. Essentially, the transparent flag means that the element exists in the COLLADA DOM content but doesn’t really exist in the XML content.
+
If the new element is created from an '''<xs:group>''' then the meta is tagged as ''transparent''. Transparent means that the IOplugin will not create an XML tag or any attributes for this element when it is saved. Essentially, the transparent flag means that the element exists in the COLLADA DOM content but doesn’t really exist in the XML content.
  
If the new element is abstract the abstract flag is set for the meta. Abstract element’s cannot be placed in the DOM.
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If the new element is abstract, the '''abstract''' flag is set for the meta. Abstract elements cannot be placed in the DOM.
  
If the element is not declared in the schema’s global scope then the isInnerClass flag is set to true. This flag is used by the metaAny content model group. Any globally declared elements can be created as part of the “any” content model but not scoped inner classes. Any other children of an “any” group become the weakly typed domAny elements.
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If the element is not declared in the schema’s global scope then the '''isInnerClass''' flag is set to true. This flag is used by the '''metaAny''' content model group. Any globally declared elements can be created as part of the “any” content model but not ''((ANDY: as part of?))'' scoped inner classes. Any other children of an “any” group become the weakly typed '''domAny''' elements.
  
Each attribute has a new metaAttribute or metaArrayAttribute created to describe it. This metaAttribute is given a name, a type, and the pointer offset into the class where the data can be found.
+
Each attribute has a new '''metaAttribute''' or '''metaArrayAttribute''' created to describe it. This '''metaAttribute''' is given a name, a type, and the pointer offset into the class where the data can be found.
  
 
The value is treated the same as a normal attribute.
 
The value is treated the same as a normal attribute.
  
If the attribute is marked required or given a default value that is also set on the metaAttribute.
+
If the attribute is marked required or given a default value, that is also set on the '''metaAttribute'''.
  
The metaCMPolicy object tree is generated to match the content model specified in the schema. Only the xs:any content model group is not supported.
+
The '''metaCMPolicy''' object tree is generated to match the content model specified in the schema. Only the '''xs:any''' content model group is not supported.
  
Any content model that contains a choice and more than one child element or an element that is the base for a substitution group will have a _contents and _contentsOrder metaAttributes added.
+
Any content model that contains a choice and more than one child element or an element that is the base for a substitution group will have '''_contents''' and '''_contentsOrder''' '''metaAttribute'''s added. ''((ANDY: Not sure where parens go around ands/ors at beginning of this sentence.))''
  
If the element’s content model contains an xs:choice group then the meta will have a _CMData metaAttribute created.
+
If the element’s content model contains an '''xs:choice''' group then the meta will have a '''_CMData''' '''metaAttribute''' created.
  
==code generator program flow & systems==
+
==Code generator program flow and systems==
  
The codegenerator is run by starting gen.php with a php interpreter. The gen.php requires at least one argument which is the schema to use for code generation.
+
The code generator is run by starting '''gen.php''' with a php interpreter. The '''gen.php''' requires at least one argument, which is the schema to use for code generation.
  
The generator, by default, creates the full integration classes. Pass an argument (after the schema) min to generate the minimal integration classes.
+
The generator, by default, creates the full integration classes. Pass an argument (after the schema) '''min''' to generate the minimal integration classes.
  
The generator, by default, puts the SCEA SNIP copyright as the header of all of the files. Pass an argument cprt for the generator to use the SCEA Shared Source License copyright as the header. This is the way the generated classes should be created.
+
The generator, by default, puts the SCEA SNIP copyright as the header of all of the files. Pass an argument '''cprt''' for the generator to use the SCEA Shared Source License copyright as the header. This is the way the generated classes should be created.
  
The generator starts by parsing the schema document and creating it’s own DOM like structure to store the info from the schema.
+
The generator starts by parsing the schema document and creating its own DOM-like structure to store the info from the schema.
  
For each schema element that might be encountered there needs to be a source file xsElementName.php . This class is used to store the data related to that element. The source file needs to be included (require_once in PHP) in the object-model.php file.
+
For each schema element that might be encountered, there needs to be a source file '''xs''ElementName''.php'''. This class is used to store the data related to that element. The source file needs to be included ('''require_once''' in PHP) in the '''object-model.php''' file.
  
Each of the object model classes has a constructor that registers what element’s and attributes (along with their min and maxOccurs) are valid for that element.
+
Each of the object model classes has a constructor that registers what elements and attributes (along with their '''min''' and '''maxOccurs''') are valid for that element.
  
The SchemaParser class uses the default PHP SAX XML parser to parse the schema document and create the custom DOM used for code generation.
+
The '''SchemaParser''' class uses the default PHP SAX XML parser to parse the schema document and create the custom DOM used for code generation.
  
The generator then gets all elements that are xs:simpleType and calls generate on them. Generate creates a TypeMeta object that contains the data needed to generate the COLLADA simple types.
+
The generator then gets all elements that are '''xs:simpleType''' and calls generate on them. Generate creates a '''TypeMeta''' object that contains the data needed to generate the COLLADA simple types.
  
Then the generator does the same for xs:complexType,  xs:group, and xs:element.
+
Then the generator does the same for '''xs:complexType,  xs:group, and xs:element'''.
  
The template-engine source file contains the logic on how to apply a template. Templates take the form of two source files. One usually suffixed with –file contains the logic on creating a new c++ source or header file and then applying another template to actually write the code.
+
The '''template-engine''' source file contains the logic on how to apply a template. Templates take the form of two source files:
 
+
* One, usually suffixed with '''–file''', contains the logic on creating a new c++ source or header file and then applying another template to actually write the code.
The most significant templates are tpl-types-header.php for generated type definitions, tpl-types-cpp.php for type registration, tpl-class-def.php for generated class interfaces, and tpl-cpp-methods for the generation of the meta for each class.
+
*''((ANDY: Is this the second of the 2 source files? Wasn't entirely clear) The most significant templates are one of:
 +
** '''tpl-types-header.php''' for generated type definitions
 +
**'''tpl-types-cpp.php''' for type registration
 +
**'''tpl-class-def.php''' for generated class interfaces
 +
**'''tpl-cpp-methods''' for the generation of the meta for each class.
  
 
[[Category:DOM project|code generator]]
 
[[Category:DOM project|code generator]]

Revision as of 21:27, 23 March 2007

Summary: The COLLADA Code Generator is/does ((ANDY: fill in summary)).

DOM generated types

The DOM's basic types are defined in daeTypes.h. There are mappings from XML Schema basic types to DOM types in daeDomTypes.h.

Any other new types defined in the schema document generate new atomic types or add name bindings to existing atomic types in the DOM.

All types defined in the schema are either restrictions, extensions, unions, or lists of existing types.

The DOM generates types in domTypes.h.

The format for most type declarations is:

typedef base_type_name domNew_type_name 

The format for list types is:

typedef daeTArray< base_type_name > domNew_type_name

Enum types take the form of “enum domNew_type_name”. Each enum value is then created as “NEW_TYPE_NAME_Enum”.

Union types are supported only for unions of enums. A new enum is generated for that union type containing the symbols and values of all enums contained in the union.

These types are registered in the registerDomTypes function found in domTypes.cpp. For all types except enums code is generated that looks like

type = daeAtomicType::get("base_type_name");

if ( type == NULL ) { //register as a raw type type = new daeRawRefType; type->_nameBindings.append("new_type_name"); daeAtomicType::append( type ); } else { //add binding to existing type type->_nameBindings.append("new_type_name "); } This code searches for a type for the base_type_name. If it finds one, it adds new_type_name as a name binding for that type. If the base type does not exist then a new rawRefType is created.

Enums always get a new type generated. The two arrays _strings and _values are populated with the enum values.

In the schema, if an enumeration has an <xs:annotation> with an <xs:appinfo> value=value, the enum created will have a value value.

DOM-generated classes

Interface

Each <xs:element> <xs:group> and <xs:complexType> generates a new daeElement subclass name domElement_name.

Each attribute and child element and a value (if it has one) gets its data storage and accessor and mutators. Array types and URIs are returned by reference. All other types are returned by value.

If an element has an xs:choice content model group and more than a single child element, it will have _contents, _contentsOrder, and _CMData arrays to store the data needed to represent the ordering of children in the content model.

An xs:complexType generates two classes:

  • The class description/interface.
  • A daeElement subclass that inherits from both daeElement and the new class interface.

Any class defined in XMLSchema global scope (not defined as a child of another element) generates a new daeElement subclass. This new element, if the type attribute is a complex type, also inherits from the complex type interface and daeElement.

An element that is part of a substitution group inherits from the element it is substitutable for. Then the DOM uses polymorphism and stores a pointer to the base class, which could be an object of any of the substitutable classes.

The code generator allows for schema type inheritance by either extension or restriction. In either case the new class inherits from the base class. Restriction is handled with the DOM meta information since C++ can do inheritance only by extension. The current (COLLADA 1.4.1) schema does not take advantage of this feature.

The code generator allows for scoped type definitions. This would happen when a simple type is created anonymously in the schema document instead of creating a global simple type and referencing it. The current (COLLADA 1.4.1) schema does not take advantage of this feature.

When generating mutators for string data attributes or values, the generator creates code:

*(daeStringRef*)&attrAttribute_name = atAttribute_name 

which lets the DOM create memory to store its string data.

The xmlns attribute is specially created only for elements that have an <xs:annotation> <xs:appinfo> that contains enable-xmlns.

Meta generation

Each element that is generated has a function registerElement. This is the function that is called to create the meta information that describes the new element.

Every element’s _Meta descriptor has a name and a pointer to the element’s creation function create(daeInt bytes).

If the new element is created from an <xs:group> then the meta is tagged as transparent. Transparent means that the IOplugin will not create an XML tag or any attributes for this element when it is saved. Essentially, the transparent flag means that the element exists in the COLLADA DOM content but doesn’t really exist in the XML content.

If the new element is abstract, the abstract flag is set for the meta. Abstract elements cannot be placed in the DOM.

If the element is not declared in the schema’s global scope then the isInnerClass flag is set to true. This flag is used by the metaAny content model group. Any globally declared elements can be created as part of the “any” content model but not ((ANDY: as part of?)) scoped inner classes. Any other children of an “any” group become the weakly typed domAny elements.

Each attribute has a new metaAttribute or metaArrayAttribute created to describe it. This metaAttribute is given a name, a type, and the pointer offset into the class where the data can be found.

The value is treated the same as a normal attribute.

If the attribute is marked required or given a default value, that is also set on the metaAttribute.

The metaCMPolicy object tree is generated to match the content model specified in the schema. Only the xs:any content model group is not supported.

Any content model that contains a choice and more than one child element or an element that is the base for a substitution group will have _contents and _contentsOrder metaAttributes added. ((ANDY: Not sure where parens go around ands/ors at beginning of this sentence.))

If the element’s content model contains an xs:choice group then the meta will have a _CMData metaAttribute created.

Code generator program flow and systems

The code generator is run by starting gen.php with a php interpreter. The gen.php requires at least one argument, which is the schema to use for code generation.

The generator, by default, creates the full integration classes. Pass an argument (after the schema) min to generate the minimal integration classes.

The generator, by default, puts the SCEA SNIP copyright as the header of all of the files. Pass an argument cprt for the generator to use the SCEA Shared Source License copyright as the header. This is the way the generated classes should be created.

The generator starts by parsing the schema document and creating its own DOM-like structure to store the info from the schema.

For each schema element that might be encountered, there needs to be a source file xsElementName.php. This class is used to store the data related to that element. The source file needs to be included (require_once in PHP) in the object-model.php file.

Each of the object model classes has a constructor that registers what elements and attributes (along with their min and maxOccurs) are valid for that element.

The SchemaParser class uses the default PHP SAX XML parser to parse the schema document and create the custom DOM used for code generation.

The generator then gets all elements that are xs:simpleType and calls generate on them. Generate creates a TypeMeta object that contains the data needed to generate the COLLADA simple types.

Then the generator does the same for xs:complexType, xs:group, and xs:element.

The template-engine source file contains the logic on how to apply a template. Templates take the form of two source files:

  • One, usually suffixed with –file, contains the logic on creating a new c++ source or header file and then applying another template to actually write the code.
  • ((ANDY: Is this the second of the 2 source files? Wasn't entirely clear) The most significant templates are one of:
    • tpl-types-header.php for generated type definitions
    • tpl-types-cpp.php for type registration
    • tpl-class-def.php for generated class interfaces
    • tpl-cpp-methods for the generation of the meta for each class.