com.sun.jna.Function Maven / Gradle / Ivy
/* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package com.sun.jna;
import java.lang.reflect.Method;
import java.util.Collections;
import java.util.Map;
/**
* An abstraction for a native function pointer. An instance of
* Function represents a pointer to some native function.
* {@link #invoke(Class,Object[],Map)} is the primary means to call
* the function.
*
* Function call behavior may be modified by passing one of the following call
* flags:
*
* - {@link Function#C_CONVENTION} Use C calling convention (default)
*
- {@link Function#ALT_CONVENTION} Use alternate calling convention (e.g. stdcall)
*
- {@link Function#THROW_LAST_ERROR} Throw a {@link LastErrorException} if
* the native function sets the system error to a non-zero value (errno or
* GetLastError). Setting this flag will cause the system error to be cleared
* prior to native function invocation.
*
*
* @author Sheng Liang, originator
* @author Todd Fast, suitability modifications
* @author Timothy Wall
* @see Pointer
*/
public class Function extends Pointer {
/** Any argument which implements this interface will have the
* {@link #read} method called immediately after function invocation.
*/
public interface PostCallRead {
/** Perform any necessary post-call synchronization. Normally this
* just means reading from native memory any changes made by
* the native function call.
*/
void read();
}
/** Maximum number of arguments supported by a JNA function call. */
public static final int MAX_NARGS = 256;
/** Standard C calling convention. */
public static final int C_CONVENTION = 0;
/** First alternate convention (currently used only for w32 stdcall). */
public static final int ALT_CONVENTION = 0x3F;
private static final int MASK_CC = 0x3F;
/** Whether to throw an exception if last error is non-zero after call. */
public static final int THROW_LAST_ERROR = 0x40;
static final Integer INTEGER_TRUE = new Integer(-1);
static final Integer INTEGER_FALSE = new Integer(0);
/**
* Obtain a Function representing a native
* function that follows the standard "C" calling convention.
*
* The allocated instance represents a pointer to the named native
* function from the named library, called with the standard "C" calling
* convention.
*
* @param libraryName
* Library in which to find the native function
* @param functionName
* Name of the native function to be linked with
* @throws UnsatisfiedLinkError if the library is not found or
* the given function name is not found within the library.
*/
public static Function getFunction(String libraryName, String functionName) {
return NativeLibrary.getInstance(libraryName).getFunction(functionName);
}
/**
* Obtain a Function representing a native
* function.
*
*
The allocated instance represents a pointer to the named native
* function from the named library.
*
* @param libraryName
* Library in which to find the function
* @param functionName
* Name of the native function to be linked with
* @param callFlags
* Function call flags
*
* @throws UnsatisfiedLinkError if the library is not found or
* the given function name is not found within the library.
*/
public static Function getFunction(String libraryName, String functionName, int callFlags) {
return NativeLibrary.getInstance(libraryName).getFunction(functionName, callFlags, null);
}
/**
* Obtain a Function representing a native
* function.
*
*
The allocated instance represents a pointer to the named native
* function from the named library.
*
* @param libraryName
* Library in which to find the function
* @param functionName
* Name of the native function to be linked with
* @param callFlags
* Function call flags
* @param encoding
* Encoding to use for conversion between Java and native
* strings.
*
* @throws UnsatisfiedLinkError if the library is not found or
* the given function name is not found within the library.
*/
public static Function getFunction(String libraryName, String functionName, int callFlags, String encoding) {
return NativeLibrary.getInstance(libraryName).getFunction(functionName, callFlags, encoding);
}
/**
* Obtain a Function representing a native
* function pointer. In general, this function should be used by dynamic
* languages; Java code should allow JNA to bind to a specific Callback
* interface instead by defining a return type or Structure field type.
*
*
The allocated instance represents a pointer to the native
* function pointer.
*
* @param p Native function pointer
*/
public static Function getFunction(Pointer p) {
return getFunction(p, 0);
}
/**
* Obtain a Function representing a native
* function pointer. In general, this function should be used by dynamic
* languages; Java code should allow JNA to bind to a specific Callback
* interface instead by defining a return type or Structure field type.
*
*
The allocated instance represents a pointer to the native
* function pointer.
*
* @param p
* Native function pointer
* @param callFlags
* Function call flags
*/
public static Function getFunction(Pointer p, int callFlags) {
return new Function(p, callFlags, null);
}
// Keep a reference to the NativeLibrary so it does not get garbage
// collected until the function is
private NativeLibrary library;
private final String functionName;
final String encoding;
final int callFlags;
final Map options;
/** For internal JNA use. */
static final String OPTION_INVOKING_METHOD = "invoking-method";
/** For checking if methods declare varargs */
private static final VarArgsChecker IS_VARARGS = VarArgsChecker.create();
/**
* Create a new Function that is linked with a native
* function that follows the given calling convention.
*
*
The allocated instance represents a pointer to the named native
* function from the supplied library, called with the given calling
* convention.
*
* @param library
* {@link NativeLibrary} in which to find the function
* @param functionName
* Name of the native function to be linked with
* @param callFlags
* Function call flags
* @param encoding
* Encoding for conversion between Java and native strings.
* @throws UnsatisfiedLinkError if the given function name is
* not found within the library.
*/
Function(NativeLibrary library, String functionName, int callFlags, String encoding) {
checkCallingConvention(callFlags & MASK_CC);
if (functionName == null)
throw new NullPointerException("Function name must not be null");
this.library = library;
this.functionName = functionName;
this.callFlags = callFlags;
this.options = library.options;
this.encoding = encoding != null
? encoding : Native.getDefaultStringEncoding();
try {
this.peer = library.getSymbolAddress(functionName);
}
catch(UnsatisfiedLinkError e) {
throw new UnsatisfiedLinkError("Error looking up function '"
+ functionName + "': "
+ e.getMessage());
}
}
/**
* Create a new Function that is linked with a native
* function that follows the given calling convention.
*
*
The allocated instance represents a pointer to the given
* function address, called with the given calling
* convention.
*
* @param functionAddress
* Address of the native function
* @param callFlags
* Function call flags
* @param encoding
* Encoding for conversion between Java and native strings.
*/
Function(Pointer functionAddress, int callFlags, String encoding) {
checkCallingConvention(callFlags & MASK_CC);
if (functionAddress == null
|| functionAddress.peer == 0) {
throw new NullPointerException("Function address may not be null");
}
this.functionName = functionAddress.toString();
this.callFlags = callFlags;
this.peer = functionAddress.peer;
this.options = Collections.EMPTY_MAP;
this.encoding = encoding != null
? encoding : Native.getDefaultStringEncoding();
}
private void checkCallingConvention(int convention)
throws IllegalArgumentException {
// TODO: perform per-platform calling convention checks
if ((convention & MASK_CC) != convention) {
throw new IllegalArgumentException("Unrecognized calling convention: "
+ convention);
}
}
public String getName() {
return functionName;
}
public int getCallingConvention() {
return callFlags & MASK_CC;
}
/** Invoke the native function with the given arguments, returning the
* native result as an Object.
*/
public Object invoke(Class returnType, Object[] inArgs) {
return invoke(returnType, inArgs, this.options);
}
/** Invoke the native function with the given arguments, returning the
* native result as an Object.
*/
public Object invoke(Class returnType, Object[] inArgs, Map options) {
Method invokingMethod = (Method)options.get(OPTION_INVOKING_METHOD);
Class[] paramTypes = invokingMethod != null ? invokingMethod.getParameterTypes() : null;
return invoke(invokingMethod, paramTypes, returnType, inArgs, options);
}
/** Invoke the native function with the given arguments, returning the
* native result as an Object. This method can be called if invoking method and parameter
* types are already at hand. When calling {@link Function#invoke(Class, Object[], Map)},
* the method has to be in the options under key {@link Function#OPTION_INVOKING_METHOD}.
*/
Object invoke(Method invokingMethod, Class[] paramTypes, Class returnType, Object[] inArgs, Map options) {
// Clone the argument array to obtain a scratch space for modified
// types/values
Object[] args = { };
if (inArgs != null) {
if (inArgs.length > MAX_NARGS) {
throw new UnsupportedOperationException("Maximum argument count is " + MAX_NARGS);
}
args = new Object[inArgs.length];
System.arraycopy(inArgs, 0, args, 0, args.length);
}
TypeMapper mapper =
(TypeMapper)options.get(Library.OPTION_TYPE_MAPPER);
boolean allowObjects = Boolean.TRUE.equals(options.get(Library.OPTION_ALLOW_OBJECTS));
boolean isVarArgs = args.length > 0 && invokingMethod != null ? isVarArgs(invokingMethod) : false;
for (int i=0; i < args.length; i++) {
Class paramType = invokingMethod != null
? (isVarArgs && i >= paramTypes.length-1
? paramTypes[paramTypes.length-1].getComponentType()
: paramTypes[i])
: null;
args[i] = convertArgument(args, i, invokingMethod,
mapper, allowObjects, paramType);
}
Class nativeReturnType = returnType;
FromNativeConverter resultConverter = null;
if (NativeMapped.class.isAssignableFrom(returnType)) {
NativeMappedConverter tc = NativeMappedConverter.getInstance(returnType);
resultConverter = tc;
nativeReturnType = tc.nativeType();
}
else if (mapper != null) {
resultConverter = mapper.getFromNativeConverter(returnType);
if (resultConverter != null) {
nativeReturnType = resultConverter.nativeType();
}
}
Object result = invoke(args, nativeReturnType, allowObjects);
// Convert the result to a custom value/type if appropriate
if (resultConverter != null) {
FromNativeContext context;
if (invokingMethod != null) {
context = new MethodResultContext(returnType, this, inArgs, invokingMethod);
} else {
context = new FunctionResultContext(returnType, this, inArgs);
}
result = resultConverter.fromNative(result, context);
}
// Sync all memory which might have been modified by the native call
if (inArgs != null) {
for (int i=0; i < inArgs.length; i++) {
Object inArg = inArgs[i];
if (inArg == null)
continue;
if (inArg instanceof Structure) {
if (!(inArg instanceof Structure.ByValue)) {
((Structure)inArg).autoRead();
}
}
else if (args[i] instanceof PostCallRead) {
((PostCallRead)args[i]).read();
if (args[i] instanceof PointerArray) {
PointerArray array = (PointerArray)args[i];
if (Structure.ByReference[].class.isAssignableFrom(inArg.getClass())) {
Class type = inArg.getClass().getComponentType();
Structure[] ss = (Structure[])inArg;
for (int si=0;si < ss.length;si++) {
Pointer p = array.getPointer(Pointer.SIZE * si);
ss[si] = Structure.updateStructureByReference(type, ss[si], p);
}
}
}
}
else if (Structure[].class.isAssignableFrom(inArg.getClass())) {
Structure.autoRead((Structure[])inArg);
}
}
}
return result;
}
/** @see NativeLibrary#NativeLibrary(String,String,long,Map) implementation */
Object invoke(Object[] args, Class returnType, boolean allowObjects) {
Object result = null;
if (returnType == null || returnType==void.class || returnType==Void.class) {
Native.invokeVoid(peer, callFlags, args);
result = null;
}
else if (returnType==boolean.class || returnType==Boolean.class) {
result = valueOf(Native.invokeInt(peer, callFlags, args) != 0);
}
else if (returnType==byte.class || returnType==Byte.class) {
result = new Byte((byte)Native.invokeInt(peer, callFlags, args));
}
else if (returnType==short.class || returnType==Short.class) {
result = new Short((short)Native.invokeInt(peer, callFlags, args));
}
else if (returnType==char.class || returnType==Character.class) {
result = new Character((char)Native.invokeInt(peer, callFlags, args));
}
else if (returnType==int.class || returnType==Integer.class) {
result = new Integer(Native.invokeInt(peer, callFlags, args));
}
else if (returnType==long.class || returnType==Long.class) {
result = new Long(Native.invokeLong(peer, callFlags, args));
}
else if (returnType==float.class || returnType==Float.class) {
result = new Float(Native.invokeFloat(peer, callFlags, args));
}
else if (returnType==double.class || returnType==Double.class) {
result = new Double(Native.invokeDouble(peer, callFlags, args));
}
else if (returnType==String.class) {
result = invokeString(callFlags, args, false);
}
else if (returnType==WString.class) {
String s = invokeString(callFlags, args, true);
if (s != null) {
result = new WString(s);
}
}
else if (Pointer.class.isAssignableFrom(returnType)) {
return invokePointer(callFlags, args);
}
else if (Structure.class.isAssignableFrom(returnType)) {
if (Structure.ByValue.class.isAssignableFrom(returnType)) {
Structure s =
Native.invokeStructure(peer, callFlags, args,
Structure.newInstance(returnType));
s.autoRead();
result = s;
}
else {
result = invokePointer(callFlags, args);
if (result != null) {
Structure s = Structure.newInstance(returnType, (Pointer)result);
s.conditionalAutoRead();
result = s;
}
}
}
else if (Callback.class.isAssignableFrom(returnType)) {
result = invokePointer(callFlags, args);
if (result != null) {
result = CallbackReference.getCallback(returnType, (Pointer)result);
}
}
else if (returnType==String[].class) {
Pointer p = invokePointer(callFlags, args);
if (p != null) {
result = p.getStringArray(0, encoding);
}
}
else if (returnType==WString[].class) {
Pointer p = invokePointer(callFlags, args);
if (p != null) {
String[] arr = p.getWideStringArray(0);
WString[] warr = new WString[arr.length];
for (int i=0;i < arr.length;i++) {
warr[i] = new WString(arr[i]);
}
result = warr;
}
}
else if (returnType==Pointer[].class) {
Pointer p = invokePointer(callFlags, args);
if (p != null) {
result = p.getPointerArray(0);
}
}
else if (allowObjects) {
result = Native.invokeObject(peer, callFlags, args);
if (result != null
&& !returnType.isAssignableFrom(result.getClass())) {
throw new ClassCastException("Return type " + returnType
+ " does not match result "
+ result.getClass());
}
}
else {
throw new IllegalArgumentException("Unsupported return type "
+ returnType
+ " in function " + getName());
}
return result;
}
private Pointer invokePointer(int callFlags, Object[] args) {
long ptr = Native.invokePointer(peer, callFlags, args);
return ptr == 0 ? null : new Pointer(ptr);
}
private Object convertArgument(Object[] args, int index,
Method invokingMethod, TypeMapper mapper,
boolean allowObjects, Class expectedType) {
Object arg = args[index];
if (arg != null) {
Class type = arg.getClass();
ToNativeConverter converter = null;
if (NativeMapped.class.isAssignableFrom(type)) {
converter = NativeMappedConverter.getInstance(type);
}
else if (mapper != null) {
converter = mapper.getToNativeConverter(type);
}
if (converter != null) {
ToNativeContext context;
if (invokingMethod != null) {
context = new MethodParameterContext(this, args, index, invokingMethod) ;
}
else {
context = new FunctionParameterContext(this, args, index);
}
arg = converter.toNative(arg, context);
}
}
if (arg == null || isPrimitiveArray(arg.getClass())) {
return arg;
}
Class argClass = arg.getClass();
// Convert Structures to native pointers
if (arg instanceof Structure) {
Structure struct = (Structure)arg;
struct.autoWrite();
if (struct instanceof Structure.ByValue) {
// Double-check against the method signature, if available
Class ptype = struct.getClass();
if (invokingMethod != null) {
Class[] ptypes = invokingMethod.getParameterTypes();
if (IS_VARARGS.isVarArgs(invokingMethod)) {
if (index < ptypes.length-1) {
ptype = ptypes[index];
}
else {
Class etype = ptypes[ptypes.length-1].getComponentType();
if (etype != Object.class) {
ptype = etype;
}
}
}
else {
ptype = ptypes[index];
}
}
if (Structure.ByValue.class.isAssignableFrom(ptype)) {
return struct;
}
}
return struct.getPointer();
}
// Convert Callback to Pointer
else if (arg instanceof Callback) {
return CallbackReference.getFunctionPointer((Callback)arg);
}
// String arguments are converted to native pointers here rather
// than in native code so that the values will be valid until
// this method returns.
// Convert String to native pointer (const)
else if (arg instanceof String) {
return new NativeString((String)arg, false).getPointer();
}
// Convert WString to native pointer (const)
else if (arg instanceof WString) {
return new NativeString(arg.toString(), true).getPointer();
}
// Default conversion of boolean to int; if you want something
// different, use a ToNativeConverter
else if (arg instanceof Boolean) {
return Boolean.TRUE.equals(arg) ? INTEGER_TRUE : INTEGER_FALSE;
}
else if (String[].class == argClass) {
return new StringArray((String[])arg, encoding);
}
else if (WString[].class == argClass) {
return new StringArray((WString[])arg);
}
else if (Pointer[].class == argClass) {
return new PointerArray((Pointer[])arg);
}
else if (NativeMapped[].class.isAssignableFrom(argClass)) {
return new NativeMappedArray((NativeMapped[])arg);
}
else if (Structure[].class.isAssignableFrom(argClass)) {
// If the signature is Structure[], disallow
// Structure.ByReference[] and Structure.ByReference elements
Structure[] ss = (Structure[])arg;
Class type = argClass.getComponentType();
boolean byRef = Structure.ByReference.class.isAssignableFrom(type);
if (expectedType != null) {
if (!Structure.ByReference[].class.isAssignableFrom(expectedType)) {
if (byRef) {
throw new IllegalArgumentException("Function " + getName()
+ " declared Structure[] at parameter "
+ index + " but array of "
+ type + " was passed");
}
for (int i=0;i < ss.length;i++) {
if (ss[i] instanceof Structure.ByReference) {
throw new IllegalArgumentException("Function " + getName()
+ " declared Structure[] at parameter "
+ index + " but element " + i
+ " is of Structure.ByReference type");
}
}
}
}
if (byRef) {
Structure.autoWrite(ss);
Pointer[] pointers = new Pointer[ss.length + 1];
for (int i=0;i < ss.length;i++) {
pointers[i] = ss[i] != null ? ss[i].getPointer() : null;
}
return new PointerArray(pointers);
}
else if (ss.length == 0) {
throw new IllegalArgumentException("Structure array must have non-zero length");
}
else if (ss[0] == null) {
Structure.newInstance(type).toArray(ss);
return ss[0].getPointer();
}
else {
Structure.autoWrite(ss);
return ss[0].getPointer();
}
}
else if (argClass.isArray()){
throw new IllegalArgumentException("Unsupported array argument type: "
+ argClass.getComponentType());
}
else if (allowObjects) {
return arg;
}
else if (!Native.isSupportedNativeType(arg.getClass())) {
throw new IllegalArgumentException("Unsupported argument type "
+ arg.getClass().getName()
+ " at parameter " + index
+ " of function " + getName());
}
return arg;
}
private boolean isPrimitiveArray(Class argClass) {
return argClass.isArray()
&& argClass.getComponentType().isPrimitive();
}
/**
* Call the native function being represented by this object
*
* @param args
* Arguments to pass to the native function
*/
public void invoke(Object[] args) {
invoke(Void.class, args);
}
/**
* Call the native function being represented by this object
*
* @param callFlags calling convention to be used
* @param args
* Arguments to pass to the native function
* @param wide whether the native string uses wchar_t;
* if false, char is assumed
* @return The value returned by the target native function, as a String
*/
private String invokeString(int callFlags, Object[] args, boolean wide) {
Pointer ptr = invokePointer(callFlags, args);
String s = null;
if (ptr != null) {
if (wide) {
s = ptr.getWideString(0);
}
else {
s = ptr.getString(0, encoding);
}
}
return s;
}
/** Provide a human-readable representation of this object. */
public String toString() {
if (library != null) {
return "native function " + functionName + "(" + library.getName()
+ ")@0x" + Long.toHexString(peer);
}
return "native function@0x" + Long.toHexString(peer);
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invokeObject(Object.class, args)}.
*/
public Object invokeObject(Object[] args) {
return invoke(Object.class, args);
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(Pointer.class, args)}.
*/
public Pointer invokePointer(Object[] args) {
return (Pointer)invoke(Pointer.class, args);
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(String.class, args)}
* or {@link #invoke(Class,Object[]) invoke(WString.class, args)}
* @param args Arguments passed to native function
* @param wide Whether the return value is of type wchar_t*;
* if false, the return value is of type char*.
*/
public String invokeString(Object[] args, boolean wide) {
Object o = invoke(wide ? WString.class : String.class, args);
return o != null ? o.toString() : null;
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(Integer.class, args)}.
*/
public int invokeInt(Object[] args) {
return ((Integer)invoke(Integer.class, args)).intValue();
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(Long.class, args)}.
*/
public long invokeLong(Object[] args) {
return ((Long)invoke(Long.class, args)).longValue();
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(Float.class, args)}.
*/
public float invokeFloat(Object[] args) {
return ((Float)invoke(Float.class, args)).floatValue();
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(Double.class, args)}.
*/
public double invokeDouble(Object[] args) {
return ((Double)invoke(Double.class, args)).doubleValue();
}
/** Convenience method for
* {@link #invoke(Class,Object[]) invoke(Void.class, args)}.
*/
public void invokeVoid(Object[] args) {
invoke(Void.class, args);
}
/** Two function pointers are equal if they share the same peer address
* and calling convention.
*/
public boolean equals(Object o) {
if (o == this) return true;
if (o == null) return false;
if (o.getClass() == getClass()) {
Function other = (Function)o;
return other.callFlags == this.callFlags
&& other.options.equals(this.options)
&& other.peer == this.peer;
}
return false;
}
/** Provide a unique hash code for {@link Function}s which are
equivalent.
*/
public int hashCode() {
return callFlags + options.hashCode() + super.hashCode();
}
/** Concatenate varargs with normal args to obtain a simple argument
* array.
*/
static Object[] concatenateVarArgs(Object[] inArgs) {
// If the final argument is an array of something other than
// primitives, Structure, or String, treat it as varargs and
// concatenate the previous arguments with the varargs elements.
if (inArgs != null && inArgs.length > 0) {
Object lastArg = inArgs[inArgs.length-1];
Class argType = lastArg != null ? lastArg.getClass() : null;
if (argType != null && argType.isArray()) {
Object[] varArgs = (Object[])lastArg;
Object[] fullArgs = new Object[inArgs.length+varArgs.length];
System.arraycopy(inArgs, 0, fullArgs, 0, inArgs.length-1);
System.arraycopy(varArgs, 0, fullArgs, inArgs.length-1, varArgs.length);
// For convenience, always append a NULL argument to the end
// of varargs, whether the called API requires it or not. If
// it is not needed, it will be ignored, but if it *is*
// required, it avoids forcing the Java client to always
// explicitly add it.
fullArgs[fullArgs.length-1] = null;
inArgs = fullArgs;
}
}
return inArgs;
}
/** Varargs are only supported on 1.5+. */
static boolean isVarArgs(Method m) {
return IS_VARARGS.isVarArgs(m);
}
private static class NativeMappedArray extends Memory implements PostCallRead {
private final NativeMapped[] original;
public NativeMappedArray(NativeMapped[] arg) {
super(Native.getNativeSize(arg.getClass(), arg));
this.original = arg;
setValue(0, original, original.getClass());
}
public void read() {
getValue(0, original.getClass(), original);
}
}
private static class PointerArray extends Memory implements PostCallRead {
private final Pointer[] original;
public PointerArray(Pointer[] arg) {
super(Pointer.SIZE * (arg.length+1));
this.original = arg;
for (int i=0;i < arg.length;i++) {
setPointer(i*Pointer.SIZE, arg[i]);
}
setPointer(Pointer.SIZE*arg.length, null);
}
public void read() {
read(0, original, 0, original.length);
}
}
/** Implementation of Boolean.valueOf for older VMs. */
static Boolean valueOf(boolean b) {
return b ? Boolean.TRUE : Boolean.FALSE;
}
}