900 lines
27 KiB
Plaintext
900 lines
27 KiB
Plaintext
/*
|
|
* Copyright 2007 Haiku, Inc. All rights reserved.
|
|
* Distributed under the terms of the MIT License.
|
|
*
|
|
* Authors:
|
|
* Niels Sascha Reedijk, niels.reedijk@gmail.com
|
|
* Alex Wilson, yourpalal2@gmail.com
|
|
* John Scipione, jscipione@gmail.com
|
|
*
|
|
* Proofreader:
|
|
* David Weizades, ddewbofh@hotmail.com
|
|
* Thom Holwerda, slakje@quicknet.nl
|
|
*
|
|
* Corresponds to:
|
|
* headers/os/support/Archivable.h rev 37751
|
|
* src/kits/support/Archivable.cpp rev 44303
|
|
*/
|
|
|
|
|
|
/*!
|
|
\file Archivable.h
|
|
\ingroup support
|
|
\ingroup libbe
|
|
\brief Provides the BArchivable interface and declares the BArchiver and
|
|
BUnarchiver classes.
|
|
*/
|
|
|
|
|
|
/*!
|
|
\class BArchivable
|
|
\ingroup support
|
|
\ingroup libbe
|
|
\brief Interface for objects that can be archived into a BMessage.
|
|
|
|
BArchivable provides an interface for objects that can be put into message
|
|
archives and extracted into objects in another location. Using this you are
|
|
able to send objects between applications, or even between computers across
|
|
networks.
|
|
|
|
BArchivable differs from BFlattenable in that BFlattenable is designed to
|
|
store objects into flat streams of data, the main objective being storage to
|
|
disk. The objective of this interface, however, is to store objects that
|
|
will later be restored as new (but identical) objects. To illustrate this
|
|
point, BArchivable objects can be restored automatically to the correct
|
|
class, whereas BFlattenable objects have a data type which you need to map
|
|
to classes manually.
|
|
|
|
Archiving is done with the Archive() method. If your class supports it, the
|
|
caller can request it to store into a deep archive, meaning that all child
|
|
objects in it will be stored. Extracting the archive works with the
|
|
Instantiate() method, which is static. Since the interface is designed to
|
|
extract objects without the caller knowing what kind of object it actually
|
|
is, the global function #instantiate_object() instantiates a message without
|
|
you manually having to determine the class the message is from. This adds
|
|
considerable flexibility and allows BArchivable to be used in combination
|
|
with other add-ons.
|
|
|
|
To provide this interface in your classes you should publicly inherit this
|
|
class. You should implement Archive() and Instantiate(), and provide one
|
|
constructor that takes one BMessage argument.
|
|
|
|
If your class holds references to other BArchivable objects that you wish
|
|
to archive, then you should consider using the BArchiver and BUnarchiver
|
|
classes in your Archive() method and archive constructor, respectively.
|
|
You should also consider implementing the AllArchived() and AllUnarchived()
|
|
methods, which were designed to ease archiving and unarchiving in such
|
|
a situation.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchivable::BArchivable(BMessage* from)
|
|
\brief Constructor. Does important behind-the-scenes work in the
|
|
unarchiving process.
|
|
|
|
If you inherit this interface you should provide at least one constructor
|
|
that takes one BMessage argument. In that constructor, you should call
|
|
your parent class' archive constructor (even if your parent class is
|
|
BArchivable).
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchivable::BArchivable()
|
|
\brief Constructor. Does nothing.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchivable::~BArchivable()
|
|
\brief Destructor. Does nothing.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn virtual status_t BArchivable::Archive(BMessage* into, bool deep) const
|
|
\brief Archive the object into a BMessage.
|
|
|
|
You should call this method from your derived implementation as it adds the
|
|
data needed to instantiate your object to the message.
|
|
|
|
\param into The message you store your object in.
|
|
\param deep If \c true, all children of this object should be archived as
|
|
well.
|
|
|
|
\retval B_OK The archive operation was successful.
|
|
\retval B_BAD_VALUE \c NULL \a archive message.
|
|
\retval B_ERROR The archive operation failed.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn static BArchivable* BArchivable::Instantiate(BMessage* archive)
|
|
\brief Static member to restore objects from messages.
|
|
|
|
You should always check that the \a archive argument actually corresponds to
|
|
your class. The automatic functions, such as #instantiate_object() and
|
|
BUnarchiver::InstantiateObject() will not choose the wrong class but manual
|
|
calls to this member might be faulty. You can verify that \c archive
|
|
stores an object of your class with the validate_instantiation() function.
|
|
|
|
\param archive The message with the data of the object to restore.
|
|
|
|
\return A pointer to a BArchivable object.
|
|
\retval You should return a pointer to the object you create with
|
|
\c archive, or \c NULL if the unarchival fails.
|
|
|
|
\warning The default implementation will always return \c NULL. Even though
|
|
it is possible to store plain BArchivable objects, it is impossible to
|
|
restore them.
|
|
|
|
\see instantiate_object(BMessage*)
|
|
\see BUnarchiver::InstantiateObject()
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn virtual status_t BArchivable::Perform(perform_code d, void* arg)
|
|
\brief Perform some action (Internal method defined for binary
|
|
compatibility purposes).
|
|
|
|
\internal This method is defined for binary compatibility purposes, it is
|
|
used to ensure that the correct AllUnarchived() and AllArchived()
|
|
methods are called for objects, as those methods are new to
|
|
Haiku.
|
|
|
|
\param d The perform code.
|
|
\param arg A pointer to store some data.
|
|
|
|
\returns A status code.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn virtual status_t BArchivable::AllUnarchived(const BMessage* archive)
|
|
\brief Method relating to the use of \c BUnarchiver.
|
|
|
|
This hook function is called triggered in the BUnarchiver::Finish() method.
|
|
In this method, you can rebuild references to objects that may be direct
|
|
children of your object, or may be children of other objects.
|
|
Implementations of this method should call the implementation of
|
|
their parent class, the same as for the Archive() method.
|
|
|
|
\warning To guarantee that your AllUnarchived() method will be called
|
|
during unarchival, you must create a BUnarchiver object in your
|
|
archive constructor.
|
|
|
|
\see BUnarchiver, BUnarchiver::Finish()
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*! \fn virtual status_t BArchivable::AllArchived(BMessage* into) const
|
|
\brief Method relating to the use of \c BArchiver.
|
|
|
|
This hook function is called once the first BArchiver that was created in
|
|
an archiving session is either destroyed, or has its Finish() method
|
|
called. Implementations of this method can be used, in conjunction with
|
|
BArchiver::IsArchived(), to reference objects in your archive that you
|
|
do not own, depending on whether or not those objects were archived by their
|
|
owners. Implementations of this method should call the implementation of
|
|
their parent class, the same as for the Archive() method.
|
|
|
|
\warning To guarantee that your AllArchived() method will be called
|
|
during archival, you must create a BArchiver object in your
|
|
Archive() implementation.
|
|
|
|
\warning You should archive any objects you own in your Archive()
|
|
method implementation, and \b NOT your AllArchived() method.
|
|
|
|
\see BArchiver BArchiver::Finish()
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
///// BArchiver /////
|
|
|
|
|
|
/*!
|
|
\class BArchiver
|
|
\ingroup support
|
|
\ingroup libbe
|
|
\brief A class that simplifies the archiving of complicated BArchivable
|
|
hierarchies.
|
|
|
|
The BArchiver class is a small class that is used for archiving of
|
|
complicated BArchivable hierarchies. Such a hierarchy may include
|
|
multiple BArchivable objects, each of which might be referenced by
|
|
many BArchivable objects. With the BArchiver class, you can be certain
|
|
that each BArchivable object is archived only once with very little work.
|
|
When used in conjuction with the BArchivable::AllArchived() and
|
|
BArchivable::AllUnarchived() methods, it is simple to rebuild your system of
|
|
references upon unarchival so that they are equivalent to those that were
|
|
present in your original hierarchy.
|
|
|
|
The objects you archive can be retrieved using a BUnarchiver object.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchiver::BArchiver(BMessage* archive)
|
|
\brief Constructs a BArchiver object that manages \c archive.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchiver::~BArchiver()
|
|
\brief Destroys a BArchiver object. If the BArchiver object has not had its
|
|
Finish() method called, this will be done now.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BArchiver::AddArchivable(const char* name,
|
|
BArchivable* archivable, bool deep = true)
|
|
\brief Adds a reference to \c archivable to the archive used to
|
|
construct this BArchiver. May call \c archivable's Archive() method.
|
|
|
|
\param name Where this reference will be stored in the archive.
|
|
\param archivable The BArchivable* object that to reference.
|
|
\param deep Passed to \c archivable->Archive() if \c archivable must
|
|
be archived.
|
|
|
|
Adds a reference to \c archivable to your archive. If \c archivable has
|
|
not yet been archived, then its Archive() method is called. BArchiver
|
|
can only track BArchivable objects that have been archived through this
|
|
method or the GetTokenForArchivable() methods.
|
|
|
|
\warning If you manually archive an object, and then pass it to
|
|
AddArchivable() or GetTokenForArchivable(), it will be archived
|
|
again, and when unarchived you will end up with two different
|
|
BArchivable objects.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BArchiver::GetTokenForArchivable(BArchivable* archivable,
|
|
bool deep, int32& _token);
|
|
\brief Get a token representing a BArchivable object for this archiving
|
|
session.
|
|
|
|
\param archivable The BArchivable object for which you wish to get a
|
|
token.
|
|
\param deep Controls how \c archivable will be archived, if it has not yet
|
|
been archived in this session.
|
|
\param[out] _token The token representing \c archivable is stored here.
|
|
|
|
Retrieves or creates a token to represent \c archivable in this archiving
|
|
session. If \c archivable has not yet been archived, it will be now. If
|
|
\c archivable gets archived, the \c deep parameter will be passed to its
|
|
Archive() method.
|
|
|
|
\warning If you manually archive an object, and then pass it to
|
|
GetTokenForArchivable(), it will be archived again, and when
|
|
unarchived you will end up with two different BArchivable objects.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BArchiver::GetTokenForArchivable(BArchivable* archivable,
|
|
int32 &_token)
|
|
\brief Equivalent to calling the expanded GetTokenForArchivable(
|
|
BArchivable*, bool, int32&), with the deep parameter equal to
|
|
\c true.
|
|
|
|
\see GetTokenForArchivable(BArchivable*, bool, int32&)
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn bool BArchiver::IsArchived(BArchivable* archivable);
|
|
\brief Returns whether \c archivable has already been archived in this
|
|
session.
|
|
|
|
\return Whether or not the object has already been archived.
|
|
\retval true \c archivable has been archived in this archiving session.
|
|
\retval false \c archivable has not been archived in this archiving session.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BArchiver::Finish(status_t err = B_OK);
|
|
\brief Report any archiving errors and possibly complete the archiving
|
|
session.
|
|
|
|
This method may finish an archiving session (triggering the call of all
|
|
archived objects' AllArchived() methods) if the following conditions
|
|
are true:
|
|
- No errors have been reported to this or any other BArchiver object
|
|
within this session.
|
|
- This is the last remaining BArchiver that has not had its Finish()
|
|
method invoked.
|
|
|
|
If you call this method with an error code not equal to B_OK, then this
|
|
archiving session has failed, archived objects will not have their
|
|
AllArchived() methods called, and any subsequent calls to this method
|
|
on any BArchiver objects in this session will return your error code.
|
|
|
|
\return The first error reported in this archiving session, or \c B_OK.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn const BMessage* BArchiver::ArchiveMessage() const
|
|
\brief Returns the BMessage* used to construct this BArchiver. This is
|
|
the archive that AddArchivable() modifies.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
///// BUnarchiver /////
|
|
|
|
|
|
/*!
|
|
\class BUnarchiver
|
|
\ingroup support
|
|
\ingroup libbe
|
|
\brief A class that simplifies the unarchiving of complicated BArchivable
|
|
hierarchies.
|
|
|
|
The BUnarchiver class is a small class used to recover BArchivable objects
|
|
that have been archived with the BArchiver class. It also provides ownership
|
|
semantics, so that memory leaks can be avoided during the unarchival
|
|
process. When retrieving an object (either via GetObject() or FindObject()),
|
|
you can specify a BUnarchiver::ownership_policy. If you specify
|
|
BUnarchiver::B_ASSUME_OWNERSHIP, you will become responsible for deleting
|
|
the retrieved item. If you specify BUnarchiver::B_DONT_ASSUME_OWNERSHIP,
|
|
you will not become responsible. You cannot take ownership of the same
|
|
object twice. After the unarchival process finishes, any unclaimed objects,
|
|
excluding the root object (the object being instantiated via
|
|
instantiate_object() or BUnarchiver::InstantiateObject()), will be deleted.
|
|
|
|
If you are updating a class that previously did not use the BArchiver and
|
|
BUnarchiver helper classes, and want to maintain backwards compatibility
|
|
with old archive, this can be done using the IsArchiveManaged() method.
|
|
|
|
\warning Calling methods on your BUnarchiver with a legacy archive (one
|
|
that was not managed by a BArchiver during archival) will result
|
|
in a call to debugger().
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\enum BUnarchiver::ownership_policy
|
|
\brief Options for the ownership policy of objects retrieved from
|
|
BUnarchiver
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\var ownership_policy BUnarchiver::B_ASSUME_OWNERSHIP
|
|
\brief Ownership of unarchived objects will be transferred to the caller.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\var ownership_policy BUnarchiver::B_DONT_ASSUME_OWNERSHIP
|
|
\brief The unarchived objects will be borrowed to the caller.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BUnarchiver::BUnarchiver(const BMessage* archive)
|
|
\brief Constructs a BUnarchiver object to manage \c archive.
|
|
|
|
\note To guarantee that your AllUnarchived() method will be called during
|
|
archival, you must create a BUnarchiver object in your archive
|
|
constructor. It is necessary to do this even if you won't use the
|
|
BUnarchiver object in your archive constructor.
|
|
|
|
\warning Do not construct a BUnarchiver object without first calling
|
|
BUnarchiver::PrepareArchive() on \c archive. It is only safe to
|
|
build a BUnarchiver without this call in your AllUnarchived()
|
|
implementation.
|
|
|
|
\see BUnarchiver::PrepareArchive()
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BUnarchiver::~BUnarchiver()
|
|
\brief Destroys a BUnarchiver object.
|
|
|
|
Calls this objects Finish() method, if it has not yet been called.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BUnarchiver::EnsureUnarchived(int32 token)
|
|
\brief Ensure the object represented by \a token is unarchived and
|
|
instantiated.
|
|
|
|
\param token the object \a token
|
|
|
|
\returns A status code.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BUnarchiver::EnsureUnarchived(const char* name,
|
|
int32 index = 0)
|
|
\brief Ensure the object archived under \a name at \a index is unarchived
|
|
and instantiated.
|
|
|
|
\param name The archive \a name.
|
|
\param index The archive \a index.
|
|
|
|
\returns A status code.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn bool BUnarchiver::IsInstantiated(int32 token)
|
|
\brief Checks whether the object represented by \c token has been
|
|
instantiated in this session.
|
|
|
|
\param token The object \a token.
|
|
|
|
\returns \c true if instantiated, \c false otherwise
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn bool BUnarchiver::IsInstantiated(const char* name, int32 index = 0)
|
|
\brief Checks whether the object archived under \a name at \a index has been
|
|
instantiated in this session.
|
|
|
|
\param name The archive \a name.
|
|
\param index The arcive \a token.
|
|
|
|
\returns \c true if instantiated, \c false otherwise.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::GetObject(int32 token,
|
|
ownership_policy owning, T*& object)
|
|
\brief Recover an object by token that was archived by a BArchiver object.
|
|
If the object has not yet been instantiated, and this request is not coming
|
|
from an AllUnarchived() implementation, the object will be instantiated now.
|
|
|
|
If the retrieved object is not of the type T, then this method will fail.
|
|
If this method fails, you will not receive ownership of the object, no
|
|
matter what you specified in \c owning.
|
|
|
|
\tparam T The type of \a object you wish to find.
|
|
|
|
\param token The \a token you got for this object from
|
|
BArchiver::GetTokenForArchivable() during archival.
|
|
\param owning Whether or not you wish to take ownership of the
|
|
retrieved object.
|
|
\param object Return parameter for the retrieved object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The object retrieved was of type T.
|
|
\retval B_BAD_TYPE The object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::GetObject(int32 token,
|
|
T*& object)
|
|
\brief Recover and take ownership of an object represented by \a token.
|
|
|
|
Equivalent to calling GetObject(token, \c B_ASSUME_OWNERSHIP, object)
|
|
|
|
\tparam T The type of \a object you wish to find.
|
|
|
|
\param token The \a token you got for this object from
|
|
BArchiver::GetTokenForArchivable() during archival.
|
|
\param object The return parameter for the retrieved object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The object retrieved was of type T.
|
|
\retval B_BAD_TYPE The object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::FindObject(const char* name,
|
|
int32 index, ownership_policy owning, T*& object)
|
|
\brief Recover an object that had previously been archived using
|
|
the BArchiver::AddArchivable() method.
|
|
|
|
If the object has not yet been instantiated, and this request is not
|
|
coming from an AllUnarchived() implementation, the object will be
|
|
instantiated now.
|
|
|
|
If the retrieved object is not of the type T, then this method will fail.
|
|
If this method fails, you will not receive ownership of the object, no
|
|
matter what you specified in \c owning.
|
|
|
|
\tparam T The type of object you wish to find.
|
|
|
|
\param name The name that was passed to BArchiver::AddArchivable() when
|
|
adding this object.
|
|
\param index The index of the object you wish to recover (\c 0-based,
|
|
like BMessage::FindData().
|
|
\param owning Dictates whether or not you wish to take ownership of the
|
|
retrieved object.
|
|
\param object Return parameter for the retrieved object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The object retrieved was of type T.
|
|
\retval B_BAD_TYPE The object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::FindObject(const char* name,
|
|
int32 index, T*& object)
|
|
\brief Recover and take ownership of an object that had previously been
|
|
archived using the BArchiver::AddArchivable() method.
|
|
|
|
\tparam T The type of object you wish to find.
|
|
|
|
\param name The name that was passed to BArchiver::AddArchivable() when
|
|
adding this object.
|
|
\param index The index of the object you wish to recover (\c 0-based,
|
|
like #BMessage::FindData().
|
|
\param object Return parameter for the retrieved object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The object retrieved was of type T.
|
|
\retval B_BAD_TYPE The object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::FindObject(const char* name,
|
|
ownership_policy owning, T*& object)
|
|
\brief Recover an object at index \c 0 that had previously been
|
|
archived using the BArchiver::AddArchivable() method.
|
|
|
|
Equivalent to calling FindObject(name, \c 0, owning, object).
|
|
|
|
\tparam T The type of \a object you wish to find.
|
|
|
|
\param name The name that was passed to BArchiver::AddArchivable() when
|
|
adding this object.
|
|
\param owning Dictates whether or not you wish to take ownership of the
|
|
retrieved object.
|
|
\param object Return parameter for the retrieved object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The object retrieved was of type T.
|
|
\retval B_BAD_TYPE The object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::FindObject(const char* name,
|
|
T*& object)
|
|
\brief Recover and take ownership of an object at index \c 0 that had
|
|
previously been archived using the BArchiver::AddArchivable() method.
|
|
|
|
Equivalent to calling FindObject(name, \c 0,
|
|
BUnarchiver::B_ASSUME_OWNERSHIP, object).
|
|
|
|
\tparam T The type of \a object you wish to find.
|
|
|
|
\param name The name that was passed to BArchiver::AddArchivable() when
|
|
adding this object.
|
|
\param object Return parameter for the retrieved \a object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The \a object retrieved was of type T.
|
|
\retval B_BAD_TYPE The \a object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn status_t BUnarchiver::Finish(status_t err = B_OK);
|
|
\brief Report any unarchiving errors and possibly complete the archiving
|
|
session.
|
|
|
|
This method may finish an unarchiving session (triggering the call of all
|
|
instantiated objects' AllUnarchived() methods) if the following conditions
|
|
are true:
|
|
|
|
- No errors have been reported to this or any other BUnarchiver
|
|
object within this session.
|
|
- This is the last remaining BUnarchiver that has not had its
|
|
Finish() method invoked.
|
|
|
|
If you call this method with an error code not equal to B_OK, then this
|
|
unarchiving session has failed, instantiated objects will not have their
|
|
AllUnarchived() methods called, and any subsequent calls to this method
|
|
on any BUnarchiver objects in this session will return your error code.
|
|
Furthermore, any objects that have been instantiated, but have not had
|
|
their ownership assumed by another object will now be deleted (excluding
|
|
the root object).
|
|
|
|
\return The first error reported in this unarchiving session, or \c B_OK.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn const BMessage* BUnarchiver::ArchiveMessage() const
|
|
\brief Returns the BMessage* used to construct this BUnarchiver.
|
|
|
|
This is the archive that FindObject() uses.
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn static bool BUnarchiver::IsArchiveManaged(const BMessage* archive)
|
|
\brief Checks whether \a archive was managed by a BArchiver object.
|
|
|
|
This method can be used to maintain archive backwards-compatibility for a
|
|
class that has been updated to use the BArchiver class. If there is a
|
|
possibility that you are may dealing with a legacy archive, you can use
|
|
this method to find out before calling any methods on your BUnarchiver
|
|
object.
|
|
|
|
Here is an example of how you might use this method. Note that you
|
|
must still call PrepareArchive(archive) either way.
|
|
|
|
\code
|
|
MyArchivableClas::MyArchivableClass(BMessage* archive)
|
|
:
|
|
BArchivable(BUnarchiver::PrepareArchive(archive))
|
|
{
|
|
BUnarchiver unarchiver(archive);
|
|
|
|
if (BUnarchiver::IsArchiveManaged(archive)) {
|
|
// ... calls to FindObject() or GetObject() here ...
|
|
} else {
|
|
// ... calls to BMessage::FindMessage() here ...
|
|
}
|
|
}
|
|
\endcode
|
|
|
|
\returns Whether \a archive was managed by a BArchiver object.
|
|
\retval true if \a archive was managed by a BArchiver object.
|
|
\retval false otherwise.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn static BMessage* BUnarchiver::PrepareArchive(BMessage* &archive)
|
|
\brief Prepares \c archive for use by a BUnarchiver.
|
|
|
|
This method must be called if you plan to use a BUnarchiver on an archive.
|
|
It must be called once for each class an object inherits from that
|
|
will use a BUnarchiver.
|
|
|
|
\warning This method \b must be called \b before a call to the
|
|
archive constructor of your parent class.
|
|
|
|
Notice the use of this method in the example provided below.
|
|
\code
|
|
MyArchivableClas::MyArchivableClas(BMessage* archive)
|
|
:
|
|
BArchivable(BUnarchiver::PrepareArchive(archive))
|
|
{
|
|
// ...
|
|
}
|
|
\endcode
|
|
|
|
\param archive The archive you wish to have prepared.
|
|
|
|
\return The same #BMessage as is passed in.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn void BUnarchiver::AssumeOwnership(BArchivable* archivable)
|
|
\brief Become the owner of \a archivable.
|
|
|
|
After calling this method you are responsible for deleting the
|
|
\a archivable.
|
|
|
|
\param archivable The \a archivable object.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn void BUnarchiver::RelinquishOwnership(BArchivable* archivable)
|
|
\brief Relinquish ownership of \a archivable. If \a archivable remains
|
|
unclaimed at the end of the unarchiving session, it will be deleted
|
|
(unless it is the root object).
|
|
|
|
\param archivable The \a archivable object.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn template<class T> status_t BUnarchiver::InstantiateObject(
|
|
BMessage* from, T*& object)
|
|
\brief Attempt to instantiate an object of type T from BMessage*
|
|
\a from.
|
|
|
|
If the instantiated object is not of type T, then it will be deleted,
|
|
and this method will return \c B_BAD_TYPE. This method is similar to
|
|
the instantiate_object() function, but provides error reporting and
|
|
protection from memory leaks.
|
|
|
|
\param from The #BMessage to instantiate from.
|
|
\param object Return parameter for the retrieved object of type T.
|
|
|
|
\returns A status code.
|
|
\retval B_OK The object retrieved was of type T.
|
|
\retval B_BAD_TYPE The object retrieved was not of type T.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
///// Global methods /////
|
|
|
|
|
|
/*!
|
|
\addtogroup support_globals
|
|
*/
|
|
|
|
|
|
//! @{
|
|
|
|
|
|
/*!
|
|
\typedef typedef BArchivable* (*instantiation_func)(BMessage*)
|
|
\brief Internal definition of a function that can instantiate objects that
|
|
have been created with the BArchivable API.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchivable* instantiate_object(BMessage *from, image_id *id)
|
|
\brief Instantiate an archived object with the object being defined in a
|
|
different application or library.
|
|
|
|
This function is similar to instantiate_object(BMessage *from), except that
|
|
it takes the \a id argument referring to an image where the object might be
|
|
stored.
|
|
|
|
\note Images are names for executable files. Image id's refer to these
|
|
executable files that have been loaded by your application. Have a
|
|
look at the kernel API for further information.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn BArchivable* instantiate_object(BMessage *from)
|
|
\brief Instantiate an archived object.
|
|
|
|
This global function will determine the base class, based on the \a from
|
|
argument, and it will call the Instantiate() function of that object to
|
|
restore it.
|
|
|
|
\param from The archived object.
|
|
|
|
\return The object returns a pointer to the instantiated object, or \c NULL
|
|
if the instantiation failed. The global \c errno variable will
|
|
contain the reason why it failed.
|
|
|
|
\see instantiate_object(BMessage *from, image_id *id)
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn bool validate_instantiation(BMessage* from, const char* className)
|
|
\brief Internal function that checks if the \a className is the same as the
|
|
one stored in the \a from message.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn instantiation_func find_instantiation_func(const char* className,
|
|
const char* signature)
|
|
\brief Internal function that searches for the instantiation func with a
|
|
specific signature. Use instantiate_object() instead.
|
|
|
|
\since Haiku R1
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn instantiation_func find_instantiation_func(const char* className)
|
|
\brief Internal function that searches for the instantiation func of a
|
|
specific class. Use instantiate_object() instead.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
/*!
|
|
\fn instantiation_func find_instantiation_func(BMessage* archive)
|
|
\brief Internal function that searches for the instantiation func that
|
|
works on the specified \a archive. Use instantiate_object() instead.
|
|
|
|
\since BeOS R3
|
|
*/
|
|
|
|
|
|
//! @}
|
|
|