Creating Cross-Platform Applications with Core Foundation and Open Source

$ rsync -vL "darwinsource.opendarwin.org::darwinsource/10.3.8/*.tar.gz" ./

"Class" is not used to refer to opaque types because, despite the conceptual similarity of class and 
opaque type, many might find the term confusing. However, the Core Foundation documentation frequently 
refers to specific, data-bearing instances of these types as "objects".

#include <CoreFoundation/CoreFoundation.h>

void propertyListExample( void );
void writePropertyListToFile( CFDataRef data );

const char * kFilename = "/schema.xml";

int main( int argc, const char * argv[] ) {
    // Create and save the plist.
    propertyListExample();

    return 0;
}

void propertyListExample( void ) {
    CFMutableDictionaryRef dict;
    CFNumberRef num;
    CFArrayRef array;
    CFDataRef data;
    #define NumKids 2
    CFStringRef kidsNames[] = { CFSTR( "John" ), CFSTR( "Kyra" ) };
    #define NumPets 0
    int yearOfBirth = 1965;
    #define NumBytesInPic 10
    const unsigned char pic[ NumBytesInPic ] = 
        { 0x3c, 0x42, 0x81, 0xa5, 0x81, 0xa5, 0x99, 0x81, 0x42, 0x3c };
    CFDataRef xmlPropertyListData;
    CFStringRef xmlAsString;

    // Create and populate a pretty standard mutable dictionary: CFString keys, CF type values.
    // To be written out as a "propertyList", the tree of CF types can contain only:
    //   CFDictionary, CFArray, CFString, CFData, CFNumber, and CFDate.
    // In addition, the keys of the dictionaries should be CFStrings.

    dict = CFDictionaryCreateMutable( NULL, 0, &kCFCopyStringDictionaryKeyCallBacks, 
        &kCFTypeDictionaryValueCallBacks );

    CFDictionarySetValue( dict, CFSTR( "Name" ), CFSTR( "John Doe" ) );

    CFDictionarySetValue( dict, CFSTR( "City of Birth" ), CFSTR( "Springfield" ) );

    num = CFNumberCreate( NULL, kCFNumberIntType, &yearOfBirth );
    CFDictionarySetValue( dict, CFSTR( "Year Of Birth" ), num );
    CFRelease( num );

    array = CFArrayCreate( NULL, ( const void ** )kidsNames, 2, &kCFTypeArrayCallBacks ); 
    CFDictionarySetValue( dict, CFSTR( "Kids Names" ), array );
    CFRelease( array );

    array = CFArrayCreate( NULL, NULL, 0, &kCFTypeArrayCallBacks );
    CFDictionarySetValue( dict, CFSTR( "Pets Names" ), array );
    CFRelease( array );

    data = CFDataCreate( NULL, pic, NumBytesInPic );
    CFDictionarySetValue( dict, CFSTR( "Picture" ), data );
    CFRelease( data );

    // We now have a dictionary which contains everything we want to know about
    // John Doe; let's show it first:

    CFShow( CFSTR( "John Doe info dictionary: " ) );
    CFShow( dict );

    // Now create a "property list", which is a flattened, XML version of the
    // dictionary:

    xmlPropertyListData = CFPropertyListCreateXMLData( NULL, dict );

   // The return value is a CFData containing the XML file; show the data

    CFShow( CFSTR( "Shown as XML property list (bytes): " ) );
    CFShow( xmlPropertyListData );

    // Given CFDatas are shown as ASCII versions of their hex contents, we can also
    // attempt to show the contents of the XML, assuming it was encoded in UTF8
    // (This is the case for XML property lists generated by CoreFoundation currently)

    xmlAsString = CFStringCreateFromExternalRepresentation( NULL, xmlPropertyListData, 
        kCFStringEncodingUTF8 );

    CFShow( CFSTR( "The XML property list contents: " ) );
    CFShow( xmlAsString );

    writePropertyListToFile( xmlPropertyListData );

    CFRelease( dict );
    CFRelease( xmlAsString );
    CFRelease( xmlPropertyListData );
}

void writePropertyListToFile( CFDataRef data ) {
    CFStringRef errorString;

    CFPropertyListRef propertyList = CFPropertyListCreateFromXMLData( NULL, data, 
        kCFPropertyListMutableContainersAndLeaves, &errorString );

    if ( errorString == NULL ) {
        CFStringRef urlString = CFStringCreateWithCString( NULL, kFilename, CFStringGetSystemEncoding() );

        CFURLRef fileURL = CFURLCreateWithFileSystemPath( NULL, urlString, kCFURLPOSIXPathStyle, FALSE );

        CFWriteStreamRef stream = CFWriteStreamCreateWithFile( NULL, fileURL );

        Boolean isOpen = CFWriteStreamOpen( stream );

        CFShow( CFSTR( "Property list (as written to file):" ) );
        CFShow( propertyList );

        CFIndex bytesWritten = CFPropertyListWriteToStream( propertyList, stream, 
            kCFPropertyListXMLFormat_v1_0, NULL );

        CFWriteStreamClose( stream );
    }
    else {
        CFShow( errorString );
        CFRelease( errorString );
    }

    CFRelease( propertyList );
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" 
    "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>City of Birth</key>
	<string>Springfield</string>
	<key>Kids Names</key>
	<array>
		<string>John</string>
		<string>Kyra</string>
	</array>
	<key>Name</key>
	<string>John Doe</string>
	<key>Pets Names</key>
	<array/>
	<key>Picture</key>
	<data>
	PEKBpYGlmYFCPA==
	</data>
	<key>Year Of Birth</key>
	<integer>1965</integer>
</dict>
</plist>

#include <CoreFoundation/CoreFoundation.h>

void readPropertyListFromFile( void );

const char * kFilename = "/schema.xml";

int main ( int argc, const char * argv[] ) {
    // Read the plist.
    readPropertyListFromFile();	

    return 0;
}

void readPropertyListFromFile( void ) {
    CFDataRef data = NULL;

    FILE *file = fopen( kFilename, "r" );

    if ( file != NULL ) {
        int result = fseek( file, 0, SEEK_END );
        result = ftell( file );
        rewind( file );

        char * buffer = ( char * )calloc( 1, result );

        if ( buffer != NULL ) {
            if ( fread( buffer, result, 1, file ) > 0 ) {			
                data = CFDataCreate( NULL, buffer, result );
            }

            free( buffer );
        } 

        fclose( file );
    }

    if ( data != NULL ) {
        CFPropertyListRef propertyList = CFPropertyListCreateFromXMLData( NULL, data,
            kCFPropertyListImmutable, NULL );

        CFShow( CFSTR( "Property list (as read from file):" ) );
        CFShow( propertyList );
    }

    CFRelease( data );
}

gcc -framework CoreFoundation -o reader main.c

$ ./reader
Property list (as read from file):
<CFDictionary 0x5009a0 [0xa01900e0]>{type = mutable, count = 6, capacity = 17, pairs = (
        1 : <CFString 0x500ad0 [0xa01900e0]>{contents = "Name"} = 
            <CFString 0x500ae0 [0xa01900e0]>{contents = "John Doe"}
        4 : <CFString 0x500b00 [0xa01900e0]>{contents = "Pets Names"} = 
            <CFArray 0x500b20 [0xa01900e0]>{type = immutable, count = 0, values = ()}
        5 : <CFString 0x500960 [0xa01900e0]>{contents = "City of Birth"} = 
            <CFString 0x500980 [0xa01900e0]>{contents = "Springfield"}
        13 : <CFString 0x500bc0 [0xa01900e0]>{contents = "Year Of Birth"} = 
             <CFNumber 0x500be0 [0xa01900e0]>{value = +1965, type = kCFNumberSInt64Type}
        16 : <CFString 0x500a90 [0xa01900e0]>{contents = "Kids Names"} = 
             <CFArray 0x500680 [0xa01900e0]>{type = mutable-small, count = 2, values = (
        0 : <CFString 0x500770 [0xa01900e0]>{contents = "John"}
        1 : <CFString 0x500640 [0xa01900e0]>{contents = "Kyra"} )}
        19 : <CFString 0x500b30 [0xa01900e0]>{contents = "Picture"} = 
             <CFData 0x500b90 [0xa01900e0]>{length = 10, capacity = 10, bytes = 0x3c4281a581a59981423c}
    )}
$ 

$ cp -R CF-299 CF-299.orig
$ patch -p0 < CF-299.linux.diff
patching file CF-299.orig/AppServices.subproj/CFUserNotification.c
Hunk #1 succeeded at 80 (offset 2 lines).
...
$

$ make install

$ make DSTROOT=/usr/lib install
...
Done!
$

$ make clean
Deleting build products...
$

#include "CFInternal.h"
#include <CoreFoundation/CFBase.h>

$ mkdir CoreFoundation
$ cd CoreFoundation
$ find ../*.subproj -name \*.h -exec ln -s {} ';'

$ make clean
Deleting build products...
$ make install
...
Done!
$

$ make > my.log  2>&1

debug:
	$(SILENT) $(ECHO) $(PLATFORM)

gcc -o reader -I/tmp/CoreFoundation.dst/usr/local/include/CoreFoundation main.c
 -L/tmp/CoreFoundation.dst/usr/local/include/CoreFoundation
 -lCoreFoundation -lpthread -lm

$ ./reader
Property list (as read from file):
<cfdictionary 0xa050958 [0x459160]>{type = mutable, count = 6, capacity = 17, pairs = (
    1 : <cfstring 0xa051330 [0x459160]>{contents = "Name"} = 
        <cfstring 0xa051348 [0x459160]>{contents = "John Doe"}
    4 : <cfstring 0xa051360 [0x459160]>{contents = "Pets Names"} = 
        <cfarray 0xa051378 [0x459160]>{type = immutable, count = 0, values = ()}
    5 : <cfstring 0xa050918 [0x459160]>{contents = "City of Birth"} = 
        <cfstring 0xa050938 [0x459160]>{contents = "Springfield"}
    13 : <cfstring 0xa051418 [0x459160]>{contents = "Year Of Birth"} = 
        <cfnumber 0xa051438 [0x459160]>{value = +1965, type = kCFNumberSInt64Type}
    16 : <cfstring 0xa050988 [0x459160]>{contents = "Kids Names"} = 
        <cfarray 0xa0509a0 [0x459160]>{type = mutable-small, count = 2, values = (
        0 : <cfstring 0xa0509b8 [0x459160]>{contents = "John"}
        1 : <cfstring 0xa051318 [0x459160]>{contents = "Kyra"}
)}
    19 : <cfstring 0xa051388 [0x459160]>{contents = "Picture"} = 
        <cfdata 0xa0513e8 [0x459160]>{length = 10, capacity = 10, bytes = 0x3c4281a581a59981423c}
)}
$

What You Need to Get Started

What is Cygwin?

CF-Lite Overview

Data types

A Property List Example

Reading the Property List on Darwin

Reading the Property List on non-Darwin systems

A Patch for Linux

Building and Deploying CF-Lite

Building and Deploying on Darwin

Building and Deploying on Linux

Building and deploying on Cygwin

Testing CF-Lite

Testing on Linux

Testing on Cygwin

Ideas for Future Exploration

Providing Feedback to Apple

For More Information

Source Code

Tools

Documentation