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CFPropertyList Reference

Overview

CFPropertyList provides functions that convert property list objects to and from several serialized formats such as XML. The CFPropertyListRef type that denotes CFPropertyList objects is an abstract type for property list objects. Depending on the contents of the XML data used to create the property list, CFPropertyListRef can be any of the property list objects: CFData, CFString, CFArray, CFDictionary, CFDate, CFBoolean, and CFNumber. Note that if you use a property list to generate XML, the keys of any dictionaries in the property list must be CFString objects.

It is important to understand that CFPropertyList provides an abstraction for all the property list types—you can think of CFPropertyList in object-oriented terms as being the superclass of CFString, CFNumber, CFDictionary, and so on. When a Core Foundation function returns a CFPropertyListRef, it means that the value may be any of the property list types. For example, CFPreferencesCopyAppValue returns a CFPropertyListRef. This means that the value returned can be a CFString object, a CFNumber object, a CFDictionary object, and so on again. You can use CFGetTypeID to determine what type of object a property list value is.

You use one of the CFPropertyListCreate... functions to create a property list object given an existing property list object, raw XML data (as in a file), or a stream. You can also convert a property list object to XML using the CFPropertyListCreateXMLData function. You use the CFPropertyListWriteToStream function to write a property list to an output stream, and validate a property list object using the CFPropertyListIsValid function. CFPropertyList properly takes care of endian issues—a property list (whether represented by a stream, XML, or a CFData object) created on a PowerPC-based Macintosh is correctly interpreted on an Intel-based Macintosh, and vice versa.

For code examples illustrating how to read and write property list files, see Property List Programming Topics for Core Foundation and in particular Saving and Restoring Property Lists.

Functions by Task

Creating a Property List

• CFPropertyListCreateDeepCopy
• CFPropertyListCreateFromXMLData
• CFPropertyListCreateFromStream

Exporting a Property List

• CFPropertyListCreateXMLData
• CFPropertyListWriteToStream

Validating a Property List

• CFPropertyListIsValid

Functions

CFPropertyListCreateDeepCopy

Recursively creates a copy of a given property list.

CFPropertyListRef CFPropertyListCreateDeepCopy (
   CFAllocatorRef allocator,
   CFPropertyListRef propertyList,
   CFOptionFlags mutabilityOption
);

Parameters

allocator

The allocator to use to allocate memory for the new property list. Pass NULL or kCFAllocatorDefault to use the current default allocator.

propertyList

The property list to copy. This may be any of the standard property list objects, for example a CFArray or a CFDictionary object.

mutabilityOption

A constant that specifies the degree of mutability of the returned property list. See Property List Mutability Options for descriptions of possible values.

Return Value

A new property list that is a copy of propertyList. Ownership follows the Create Rule.

Discussion

Recursively creates a copy of the given property list so nested arrays and dictionaries are copied as well as the top-most container.

Availability

• Available in CarbonLib v1.1 and later.
• Available in Mac OS X v10.0 and later.

Related Sample Code

• MoreIsBetter
• MoreSCF
• QISA

Declared In

CFPropertyList.h

CFPropertyListCreateFromStream

Creates a property list using data from a stream.

CFPropertyListRef CFPropertyListCreateFromStream (
   CFAllocatorRef allocator,
   CFReadStreamRef stream,
   CFIndex streamLength,
   CFOptionFlags mutabilityOption,
   CFPropertyListFormat *format,
   CFStringRef *errorString
);

Parameters

allocator

The allocator to use to allocate memory for the new property list. Pass NULL or kCFAllocatorDefault to use the current default allocator.

stream

The stream whose data contains the content. The stream must be opened and configured—this function simply reads bytes from the stream. The stream may contain any supported property list type (see Property List Formats).

streamLength

The number of bytes to read. If 0, this function will read to the end of the stream.

mutabilityOption

A constant that specifies the degree of mutability for the returned property list. See Property List Mutability Options for descriptions of possible values.

format

A constant that specifies the format of the property list. See Property List Formats for possible values.

errorString

On return, NULL if the conversion is successful, otherwise a string that describes the nature of the error. Error messages are not localized, but may be in the future, so they are not suitable for comparison.

Pass NULL if you do not wish to receive an error string. Ownership follows the Create Rule.

Return Value

A new property list initialized with the data contained in stream. Ownership follows the Create Rule.

Discussion

This function simply reads bytes from stream starting at the current location to the end, which is expected to be the end of the property list, or up to the number of bytes specified by streamLength if it is not 0.

Availability

• Available in Mac OS X v10.2 and later.

Declared In

CFPropertyList.h

CFPropertyListCreateFromXMLData

Creates a property list using the specified XML or binary property list data.

CFPropertyListRef CFPropertyListCreateFromXMLData (
   CFAllocatorRef allocator,
   CFDataRef xmlData,
   CFOptionFlags mutabilityOption,
   CFStringRef *errorString
);

Parameters

allocator

The allocator to use to allocate memory for the new property list. Pass NULL or kCFAllocatorDefault to use the current default allocator.

data

The raw bytes to convert into a property list. The bytes may be the content of an XML file or of a binary property list (see Property List Formats).

mutabilityOption

A constant that specifies the degree of mutability for the returned property list. See Property List Mutability Options for descriptions of possible values.

errorString

On return, NULL if the conversion is successful, otherwise a string that describes the nature of the error. Error messages are not localized, but may be in the future, so they are not currently suitable for comparison.

Pass NULL if you do not wish to receive an error string. Ownership follows the Create Rule.

Return Value

A new property list if the conversion is successful, otherwise NULL. Ownership follows the Create Rule.

Availability

• Available in CarbonLib v1.0 and later.
• Available in Mac OS X v10.0 and later.

Related Sample Code

• BSDLLCTest
• HID Utilities Source
• MoreIsBetter
• QISA
• StickiesExample

Declared In

CFPropertyList.h

CFPropertyListCreateXMLData

Creates an XML representation of the specified property list.

CFDataRef CFPropertyListCreateXMLData (
   CFAllocatorRef allocator,
   CFPropertyListRef propertyList
);

Parameters

allocator

The allocator to use to allocate memory for the new data object. Pass NULL or kCFAllocatorDefault to use the current default allocator.

propertyList

The property list to convert. This may be any of the standard property list objects, for example a CFArray or a CFDictionary object.

Return Value

A CFData object containing the XML data. Ownership follows the Create Rule.

Availability

• Available in CarbonLib v1.0 and later.
• Available in Mac OS X v10.0 and later.

Related Sample Code

• BSDLLCTest
• CFPrefTopScores
• MoreIsBetter
• QISA
• StickiesExample

Declared In

CFPropertyList.h

CFPropertyListIsValid

Determines if a property list is valid.

Boolean CFPropertyListIsValid (
   CFPropertyListRef plist,
   CFPropertyListFormat format
);

Parameters

plist

The property list to validate.

format

A constant that specifies the allowable format of plist. See Property List Formats for possible values.

Return Value

true if the object graph rooted at plist is a valid property list graph—that is, the property list contains no cycles, only contains property list objects, and all dictionary keys are strings; otherwise false.

Discussion

The debugging library version of this function prints out some useful messages.

Availability

• Available in Mac OS X v10.2 and later.

Declared In

CFPropertyList.h

CFPropertyListWriteToStream

Writes the bytes of a property list serialization out to a stream.

CFIndex CFPropertyListWriteToStream (
   CFPropertyListRef propertyList,
   CFWriteStreamRef stream,
   CFPropertyListFormat format,
   CFStringRef *errorString
);

Parameters

propertyList

The property list to write out.

stream

The stream to write to. The stream must be opened and configured—this function simply writes bytes to the stream.

format

A constant that specifies the format used to write propertyList. See Property List Formats for possible values.

errorString

On return, NULL if the conversion is successful, otherwise a string that describes the nature of the errors. Error messages are not localized, but may be in the future, so they are not currently suitable for comparison.

Pass NULL if you do not wish to receive an error string. Ownership follows the Create Rule.

Return Value

The number of bytes written, or 0 if an error occurred. If 0 is returned, errorString will contain an error message.

Discussion

This function leaves the stream open after reading the content. When reading a property list, this function expects the reading stream to end wherever the writing ended, so that the end of the property list data can be identified.

Availability

• Available in Mac OS X v10.2 and later.

Declared In

CFPropertyList.h

Data Types

CFPropertyListRef

A reference to a CFPropertyList object.

typedef CFTypeRef CFPropertyListRef;

Discussion

This is an abstract type for property list objects. The return value of the CFPropertyListCreateFromXMLData function depends on the contents of the given XML data. CFPropertyListRef can be a reference to any of the property list objects: CFData, CFString, CFArray, CFDictionary, CFDate, CFBoolean, and CFNumber.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBase.h

Constants

Property List Formats

Specifies the format of a property list.

enum CFPropertyListFormat {
   kCFPropertyListOpenStepFormat = 1,
   kCFPropertyListXMLFormat_v1_0 = 100,
   kCFPropertyListBinaryFormat_v1_0 = 200
};
typedef enum CFPropertyListFormat CFPropertyListFormat;

Constants

kCFPropertyListOpenStepFormat

OpenStep format (use of this format is discouraged).

Available in Mac OS X v10.2 and later.

Declared in CFPropertyList.h.

kCFPropertyListXMLFormat_v1_0

XML format version 1.0.

Available in Mac OS X v10.2 and later.

Declared in CFPropertyList.h.

kCFPropertyListBinaryFormat_v1_0

Binary format version 1.0.

Available in Mac OS X v10.2 and later.

Declared in CFPropertyList.h.

Property List Mutability Options

Option flags that determine the degree of mutability of newly created property lists.

enum CFPropertyListMutabilityOptions {
   kCFPropertyListImmutable = 0,
   kCFPropertyListMutableContainers = 1,
   kCFPropertyListMutableContainersAndLeaves = 2
};
typedef enum CFPropertyListMutabilityOptions CFPropertyListMutabilityOptions;

Constants

kCFPropertyListImmutable

Specifies that the property list should be immutable.

Available in Mac OS X v10.0 and later.

Declared in CFPropertyList.h.

kCFPropertyListMutableContainers

Specifies that the property list should have mutable containers but immutable leaves.

Available in Mac OS X v10.0 and later.

Declared in CFPropertyList.h.

kCFPropertyListMutableContainersAndLeaves

Specifies that the property list should have mutable containers and mutable leaves.

Available in Mac OS X v10.0 and later.

Declared in CFPropertyList.h.

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