pkgs/jnigen/lib/src/bindings/c_bindings.dart - native.git - Git at Google

 // Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 import '../config/config.dart';
 import '../elements/elements.dart';
 import 'c_generator.dart';

 class CBindingGenerator {
   static const classVarPrefix = '_c';
   static const methodVarPrefix = '_m';
   static const fieldVarPrefix = '_f';
   static final indent = ' ' * 4;
   static const jniResultType = 'JniResult';
   static const ifError =
       '(JniResult){.value = {.j = 0}, .exception = check_exception()}';

   // These should be avoided in parameter names.
   static const _cTypeKeywords = {
     'short',
     'char',
     'int',
     'long',
     'float',
     'double',
   };

   String _renameCParam(String paramName) =>
       _cTypeKeywords.contains(paramName) ? '${paramName}0' : paramName;

   CBindingGenerator(this.config);
   Config config;

   String generateBinding(ClassDecl c) => _class(c);

   String _class(ClassDecl c) {
     final s = StringBuffer();
     final classNameInC = c.uniqueName;
     // global variable in C that holds the reference to class
     final classVar = '${classVarPrefix}_$classNameInC';
     s.write('// ${c.binaryName}\n'
         'jclass $classVar = NULL;\n\n');

     for (var m in c.methods) {
       s.write(_method(c, m));
       s.writeln();
     }

     for (var f in c.fields) {
       final fieldBinding = _field(c, f);
       s.write(fieldBinding);
       // Fields are skipped if they're static final. In that case
       // do not write too much whitespace.
       if (fieldBinding.isNotEmpty) s.writeln();
     }
     return s.toString();
   }

   String getCType(String binaryName) {
     switch (binaryName) {
       case "void":
         return "void";
       case "byte":
         return "int8_t";
       case "char":
         return "uint16_t";
       case "double":
         return "double";
       case "float":
         return "float";
       case "int":
         return "int32_t";
       case "long":
         return "int64_t";
       case "short":
         return "int16_t";
       case "boolean":
         return "uint8_t";
       default:
         return "jobject";
     }
   }

   String _method(ClassDecl c, Method m) {
     final classNameInC = c.uniqueName;
     final isACtor = m.isCtor;
     final isStatic = m.isStatic;

     final s = StringBuffer();
     final cMethodName = m.accept(const CMethodName());
     final classRef = '${classVarPrefix}_$classNameInC';
     final methodID = '${methodVarPrefix}_$cMethodName';
     final cMethodParams = _formalArgs(m);
     final jniSignature = m.accept(const MethodSignature());
     final ifStaticMethodID = isStatic ? 'static_' : '';

     var javaReturnType = m.returnType.name;
     if (isACtor) {
       javaReturnType = c.binaryName;
     }
     final callType = _typeNameAtCallSite(m.returnType);
     final callArgs = _callArgs(m, classRef, methodID);

     var ifAssignResult = '';
     if (javaReturnType != 'void') {
       ifAssignResult = '${getCType(javaReturnType)} _result = ';
     }

     final ifStaticCall = isStatic ? 'Static' : '';
     final envMethod =
         isACtor ? 'NewObject' : 'Call$ifStaticCall${callType}Method';
     final returnResultIfAny = _result(m);
     s.write('''
 jmethodID $methodID = NULL;
 FFI_PLUGIN_EXPORT
 $jniResultType $cMethodName($cMethodParams) {
     $_loadEnvCall
     ${_loadClassCall(classRef, c.internalName)}
     load_${ifStaticMethodID}method($classRef,
       &$methodID, "${m.name}", "$jniSignature");
     if ($methodID == NULL) return $ifError;
     $ifAssignResult(*jniEnv)->$envMethod($callArgs);
     $returnResultIfAny
 }\n''');
     return s.toString();
   }

   String _field(ClassDecl c, Field f) {
     final cClassName = c.uniqueName;
     final isStatic = f.isStatic;

     final fieldName = f.finalName;
     final fieldNameInC = f.accept(const CFieldName());
     final fieldVar = "${fieldVarPrefix}_$fieldNameInC";

     // If the field is final and default is assigned, then no need to wrap
     // this field. It should then be a constant in dart code.
     if (isStatic && f.isFinal && f.defaultValue != null) {
       return "";
     }

     final s = StringBuffer();

     s.write('jfieldID $fieldVar = NULL;\n');

     final classVar = '${classVarPrefix}_$cClassName';
     void writeAccessor({bool isSetter = false}) {
       const cReturnType = jniResultType;
       final cMethodPrefix = isSetter ? 'set' : 'get';
       final formalArgs = <String>[
         if (!isStatic) 'jobject self_',
         if (isSetter) '${getCType(f.type.name)} value',
       ].join(', ');
       final ifStaticField = isStatic ? 'static_' : '';
       final ifStaticCall = isStatic ? 'Static' : '';
       final callType = _typeNameAtCallSite(f.type);
       final objectArgument = isStatic ? classVar : 'self_';

       String accessorStatements;
       if (isSetter) {
         accessorStatements =
             '$indent(*jniEnv)->Set$ifStaticCall${callType}Field(jniEnv, '
             '$objectArgument, $fieldVar, value);\n'
             '${indent}return $ifError;';
       } else {
         final getterExpr =
             '(*jniEnv)->Get$ifStaticCall${callType}Field(jniEnv, '
             '$objectArgument, $fieldVar)';
         final cResultType = getCType(f.type.name);
         final unionField = getJValueField(f.type);
         final String returnExpr;
         if (f.type.kind != Kind.primitive) {
           returnExpr = 'to_global_ref_result(_result)';
         } else {
           returnExpr = '(JniResult){.value = '
               '{.$unionField = _result}, .exception = check_exception()}';
         }
         accessorStatements = '$indent$cResultType _result = $getterExpr;\n'
             '${indent}return $returnExpr;';
       }

       s.write('''
 FFI_PLUGIN_EXPORT
 $cReturnType ${cMethodPrefix}_$fieldNameInC($formalArgs) {
     $_loadEnvCall
     ${_loadClassCall(classVar, c.internalName)}
     load_${ifStaticField}field($classVar, &$fieldVar, "$fieldName",
       "${f.type.accept(const Descriptor())}");
 $accessorStatements
 }\n\n''');
     }

     writeAccessor(isSetter: false);
     if (f.isFinal) {
       return s.toString();
     }
     writeAccessor(isSetter: true);
     return s.toString();
   }

   final String _loadEnvCall = '${indent}load_env();';

   String _loadClassCall(String classVar, String internalName) {
     return '${indent}load_class_global_ref(&$classVar, "$internalName");\n'
         '${indent}if ($classVar == NULL) return $ifError;';
   }

   String _formalArgs(Method m) {
     final args = <String>[];
     if (!m.isCtor && !m.isStatic) {
       // The underscore-suffixed name prevents accidental collision with
       // parameter named self, if any.
       args.add('jobject self_');
     }

     for (var param in m.params) {
       final paramName = _renameCParam(param.name);
       args.add('${getCType(param.type.name)} $paramName');
     }

     return args.join(", ");
   }

   String getJValueField(TypeUsage type) {
     const primitives = {
       'boolean': 'z',
       'byte': 'b',
       'short': 's',
       'char': 'c',
       'int': 'i',
       'long': 'j',
       'float': 'f',
       'double': 'd',
       'void': 'j', // in case of void return, just write 0 to largest field.
     };
     if (type.kind == Kind.primitive) {
       return primitives[type.name]!;
     }
     return 'l';
   }

   // Returns arguments at call site, concatenated by `,`.
   String _callArgs(Method m, String classVar, String methodVar) {
     final args = ['jniEnv'];
     if (!m.isCtor && !m.isStatic) {
       args.add('self_');
     } else {
       args.add(classVar);
     }
     args.add(methodVar);
     for (var param in m.params) {
       final paramName = _renameCParam(param.name);
       args.add(paramName);
     }
     return args.join(', ');
   }

   String _result(Method m) {
     final cReturnType = getCType(m.returnType.name);
     String valuePart;
     String unionField;
     if (cReturnType == 'jobject' || m.isCtor) {
       return '${indent}return to_global_ref_result(_result);';
     } else if (cReturnType == 'void') {
       // in case of void return, just write 0 in result part of JniResult
       unionField = 'j';
       valuePart = '0';
     } else {
       unionField = getJValueField(m.returnType);
       valuePart = '_result';
     }
     const exceptionPart = 'check_exception()';
     return '${indent}return (JniResult){.value = {.$unionField = $valuePart}, '
         '.exception = $exceptionPart};';
   }

   /// Returns capitalized java type name to be used as in call${type}Method
   /// or get${type}Field etc..
   String _typeNameAtCallSite(TypeUsage type) {
     if (type.kind == Kind.primitive) {
       return type.name.substring(0, 1).toUpperCase() + type.name.substring(1);
     }
     return "Object";
   }
 }

 class CPreludes {
   static const autoGeneratedNotice = '// Autogenerated by jnigen. '
       'DO NOT EDIT!\n\n';
   static const includes = '#include <stdint.h>\n'
       '#include "jni.h"\n'
       '#include "dartjni.h"\n'
       '\n';
   static const defines = 'thread_local JNIEnv *jniEnv;\n'
       'JniContext *jni;\n\n'
       'JniContext *(*context_getter)(void);\n'
       'JNIEnv *(*env_getter)(void);\n'
       '\n';
   static const initializers = 'void setJniGetters(JniContext *(*cg)(void),\n'
       '        JNIEnv *(*eg)(void)) {\n'
       '    context_getter = cg;\n'
       '    env_getter = eg;\n'
       '}\n'
       '\n';
   static const prelude =
       autoGeneratedNotice + includes + defines + initializers;
 }
	// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	import '../config/config.dart';
	import '../elements/elements.dart';
	import 'c_generator.dart';

	class CBindingGenerator {
	static const classVarPrefix = '_c';
	static const methodVarPrefix = '_m';
	static const fieldVarPrefix = '_f';
	static final indent = ' ' * 4;
	static const jniResultType = 'JniResult';
	static const ifError =
	'(JniResult){.value = {.j = 0}, .exception = check_exception()}';

	// These should be avoided in parameter names.
	static const _cTypeKeywords = {
	'short',
	'char',
	'int',
	'long',
	'float',
	'double',
	};

	String _renameCParam(String paramName) =>
	_cTypeKeywords.contains(paramName) ? '${paramName}0' : paramName;

	CBindingGenerator(this.config);
	Config config;

	String generateBinding(ClassDecl c) => _class(c);

	String _class(ClassDecl c) {
	final s = StringBuffer();
	final classNameInC = c.uniqueName;
	// global variable in C that holds the reference to class
	final classVar = '${classVarPrefix}_$classNameInC';
	s.write('// ${c.binaryName}\n'
	'jclass $classVar = NULL;\n\n');

	for (var m in c.methods) {
	s.write(_method(c, m));
	s.writeln();
	}

	for (var f in c.fields) {
	final fieldBinding = _field(c, f);
	s.write(fieldBinding);
	// Fields are skipped if they're static final. In that case
	// do not write too much whitespace.
	if (fieldBinding.isNotEmpty) s.writeln();
	}
	return s.toString();
	}

	String getCType(String binaryName) {
	switch (binaryName) {
	case "void":
	return "void";
	case "byte":
	return "int8_t";
	case "char":
	return "uint16_t";
	case "double":
	return "double";
	case "float":
	return "float";
	case "int":
	return "int32_t";
	case "long":
	return "int64_t";
	case "short":
	return "int16_t";
	case "boolean":
	return "uint8_t";
	default:
	return "jobject";
	}
	}

	String _method(ClassDecl c, Method m) {
	final classNameInC = c.uniqueName;
	final isACtor = m.isCtor;
	final isStatic = m.isStatic;

	final s = StringBuffer();
	final cMethodName = m.accept(const CMethodName());
	final classRef = '${classVarPrefix}_$classNameInC';
	final methodID = '${methodVarPrefix}_$cMethodName';
	final cMethodParams = _formalArgs(m);
	final jniSignature = m.accept(const MethodSignature());
	final ifStaticMethodID = isStatic ? 'static_' : '';

	var javaReturnType = m.returnType.name;
	if (isACtor) {
	javaReturnType = c.binaryName;
	}
	final callType = _typeNameAtCallSite(m.returnType);
	final callArgs = _callArgs(m, classRef, methodID);

	var ifAssignResult = '';
	if (javaReturnType != 'void') {
	ifAssignResult = '${getCType(javaReturnType)} _result = ';
	}

	final ifStaticCall = isStatic ? 'Static' : '';
	final envMethod =
	isACtor ? 'NewObject' : 'Call$ifStaticCall${callType}Method';
	final returnResultIfAny = _result(m);
	s.write('''
	jmethodID $methodID = NULL;
	FFI_PLUGIN_EXPORT
	$jniResultType $cMethodName($cMethodParams) {
	$_loadEnvCall
	${_loadClassCall(classRef, c.internalName)}
	load_${ifStaticMethodID}method($classRef,
	&$methodID, "${m.name}", "$jniSignature");
	if ($methodID == NULL) return $ifError;
	$ifAssignResult(*jniEnv)->$envMethod($callArgs);
	$returnResultIfAny
	}\n''');
	return s.toString();
	}

	String _field(ClassDecl c, Field f) {
	final cClassName = c.uniqueName;
	final isStatic = f.isStatic;

	final fieldName = f.finalName;
	final fieldNameInC = f.accept(const CFieldName());
	final fieldVar = "${fieldVarPrefix}_$fieldNameInC";

	// If the field is final and default is assigned, then no need to wrap
	// this field. It should then be a constant in dart code.
	if (isStatic && f.isFinal && f.defaultValue != null) {
	return "";
	}

	final s = StringBuffer();

	s.write('jfieldID $fieldVar = NULL;\n');

	final classVar = '${classVarPrefix}_$cClassName';
	void writeAccessor({bool isSetter = false}) {
	const cReturnType = jniResultType;
	final cMethodPrefix = isSetter ? 'set' : 'get';
	final formalArgs = <String>[
	if (!isStatic) 'jobject self_',
	if (isSetter) '${getCType(f.type.name)} value',
	].join(', ');
	final ifStaticField = isStatic ? 'static_' : '';
	final ifStaticCall = isStatic ? 'Static' : '';
	final callType = _typeNameAtCallSite(f.type);
	final objectArgument = isStatic ? classVar : 'self_';

	String accessorStatements;
	if (isSetter) {
	accessorStatements =
	'$indent(*jniEnv)->Set$ifStaticCall${callType}Field(jniEnv, '
	'$objectArgument, $fieldVar, value);\n'
	'${indent}return $ifError;';
	} else {
	final getterExpr =
	'(*jniEnv)->Get$ifStaticCall${callType}Field(jniEnv, '
	'$objectArgument, $fieldVar)';
	final cResultType = getCType(f.type.name);
	final unionField = getJValueField(f.type);
	final String returnExpr;
	if (f.type.kind != Kind.primitive) {
	returnExpr = 'to_global_ref_result(_result)';
	} else {
	returnExpr = '(JniResult){.value = '
	'{.$unionField = _result}, .exception = check_exception()}';
	}
	accessorStatements = '$indent$cResultType _result = $getterExpr;\n'
	'${indent}return $returnExpr;';
	}

	s.write('''
	FFI_PLUGIN_EXPORT
	$cReturnType ${cMethodPrefix}_$fieldNameInC($formalArgs) {
	$_loadEnvCall
	${_loadClassCall(classVar, c.internalName)}
	load_${ifStaticField}field($classVar, &$fieldVar, "$fieldName",
	"${f.type.accept(const Descriptor())}");
	$accessorStatements
	}\n\n''');
	}

	writeAccessor(isSetter: false);
	if (f.isFinal) {
	return s.toString();
	}
	writeAccessor(isSetter: true);
	return s.toString();
	}

	final String _loadEnvCall = '${indent}load_env();';

	String _loadClassCall(String classVar, String internalName) {
	return '${indent}load_class_global_ref(&$classVar, "$internalName");\n'
	'${indent}if ($classVar == NULL) return $ifError;';
	}

	String _formalArgs(Method m) {
	final args = <String>[];
	if (!m.isCtor && !m.isStatic) {
	// The underscore-suffixed name prevents accidental collision with
	// parameter named self, if any.
	args.add('jobject self_');
	}

	for (var param in m.params) {
	final paramName = _renameCParam(param.name);
	args.add('${getCType(param.type.name)} $paramName');
	}

	return args.join(", ");
	}

	String getJValueField(TypeUsage type) {
	const primitives = {
	'boolean': 'z',
	'byte': 'b',
	'short': 's',
	'char': 'c',
	'int': 'i',
	'long': 'j',
	'float': 'f',
	'double': 'd',
	'void': 'j', // in case of void return, just write 0 to largest field.
	};
	if (type.kind == Kind.primitive) {
	return primitives[type.name]!;
	}
	return 'l';
	}

	// Returns arguments at call site, concatenated by `,`.
	String _callArgs(Method m, String classVar, String methodVar) {
	final args = ['jniEnv'];
	if (!m.isCtor && !m.isStatic) {
	args.add('self_');
	} else {
	args.add(classVar);
	}
	args.add(methodVar);
	for (var param in m.params) {
	final paramName = _renameCParam(param.name);
	args.add(paramName);
	}
	return args.join(', ');
	}

	String _result(Method m) {
	final cReturnType = getCType(m.returnType.name);
	String valuePart;
	String unionField;
	if (cReturnType == 'jobject' \|\| m.isCtor) {
	return '${indent}return to_global_ref_result(_result);';
	} else if (cReturnType == 'void') {
	// in case of void return, just write 0 in result part of JniResult
	unionField = 'j';
	valuePart = '0';
	} else {
	unionField = getJValueField(m.returnType);
	valuePart = '_result';
	}
	const exceptionPart = 'check_exception()';
	return '${indent}return (JniResult){.value = {.$unionField = $valuePart}, '
	'.exception = $exceptionPart};';
	}

	/// Returns capitalized java type name to be used as in call${type}Method
	/// or get${type}Field etc..
	String _typeNameAtCallSite(TypeUsage type) {
	if (type.kind == Kind.primitive) {
	return type.name.substring(0, 1).toUpperCase() + type.name.substring(1);
	}
	return "Object";
	}
	}

	class CPreludes {
	static const autoGeneratedNotice = '// Autogenerated by jnigen. '
	'DO NOT EDIT!\n\n';
	static const includes = '#include <stdint.h>\n'
	'#include "jni.h"\n'
	'#include "dartjni.h"\n'
	'\n';
	static const defines = 'thread_local JNIEnv *jniEnv;\n'
	'JniContext *jni;\n\n'
	'JniContext (context_getter)(void);\n'
	'JNIEnv (env_getter)(void);\n'
	'\n';
	static const initializers = 'void setJniGetters(JniContext (cg)(void),\n'
	' JNIEnv (eg)(void)) {\n'
	' context_getter = cg;\n'
	' env_getter = eg;\n'
	'}\n'
	'\n';
	static const prelude =
	autoGeneratedNotice + includes + defines + initializers;
	}