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...object does. Also in regards to the buffer object, it is not possible to simply replace the buffer object with the bytes object and maintain backwards compatibility. The buffer object provides a mechanism to take the PyBufferProcs supplied pointer of another object and present it as its own. Since the behavior of the other object can not be guaranteed to follow the same set of strict rules that a bytes object does, it can't be used in places that a bytes object could. The array module supports...
...Object State Here is the internal state that the CPython runtime keeps for each Python object: PyObject.ob_refcnt: the object's refcount _PyGC_Head: (optional) the object's node in a list of "GC" objects _PyObject_HEAD_EXTRA: (optional) the object's node in the list of heap objects ob_refcnt is part of the memory allocated for every object. However, _PyObject_HEAD_EXTRA is allocated only if CPython was built with Py_TRACE_REFS defined. PyGC_Head is allocated only if the object's type has Py_T...
...objects, which don't exist. If the object being finalized is not part of the CI/CT: by definition, objects in the CI/CT don't have any references pointing to them from outside the CI/CT. Therefore, the finalizer cannot reach any zombie object (that is, even if the object being finalized was itself referenced from a zombie object). Now for the second issue. There are three potential cases: The finalizer clears an existing reference to a CI object. The CI object may be disposed of before the ...
...Object)', it returns a new vref object such that MyVref.object == MyObject. MyVref.object would then change to Nothing if MyObject is ever deallocated. For a concrete example, we may introduce some new C-style syntax: & -- unary operator, creates a vref on an object, same as vref.new(). * -- unary operator, dereference a vref, same as VrefObject.object. We can then define: 1. type(&MyObject) == vref.VrefType 2. *(&MyObject) == MyObject 3. (*(&MyObject)).attr == MyOb...
...objects: regular objects (like lists, ints, functions) and meta-objects. Types and classes are meta-objects. Meta-objects are also regular objects, but we're mostly interested in them because they are referenced by the __class__ attribute of regular objects (or by the __bases__ attribute of other meta-objects). The class introspection API consists of the following elements: the __class__ and __dict__ attributes on regular objects; the __bases__ and __dict__ attributes on meta-objects; preceden...
...object to be adapted protocol, the protocol requested of the object alternate, an optional object to return if the object could not be adapted A successful result of the adapt() function returns either the object passed obj, if the object is already compliant with the protocol, or a secondary object wrapper, which provides a view of the object compliant with the protocol. The definition of wrapper is deliberately vague, and a wrapper is allowed to be a full object with its own state if necessa...
...object changes or save objects. Applications should not have to explicitly query most objects. Typically, some "root" objects will be explicitly retrieved and other objects will be retrieved through normal Python object traversal. Application objects should not contain storage code, such as SQL statements or file operations, needed to provide their persistence. Application code may need to contain code to generate persistence-related events, but even these sho...
...object, as determined by hash() on that object not raising a TypeError, then the object is returned directly. If freeze() is passed a mutable object (i.e. hash() of that object raises a TypeError), then freeze() will call that object's __freeze__() method to get an immutable copy. If the object does not have a __freeze__() method, then a TypeError is raised. Sample implementations Here is a Python implementation of the freeze() built-in: def freeze(obj): try: hash(obj) re...
...object is an instance of functools.partial, construct a new Signature from its partial.func attribute, and account for already bound partial.args and partial.kwargs If the object is a class or metaclass: If the object's type has a __call__ method defined in its MRO, return a Signature for it If the object has a __new__ method defined in its MRO, return a Signature object for it If the object has a __init__ method defined in its MRO, return a Signature object for it Return signature(object.__ca...
...object is created, it already comes with a reference count of one. The API manual says of this situation that you "own" a reference. (You don't own the object -- it may be shared. E.g. small integers and short strings are cached and shared aggressively -- but that doesn't affect whether you own a reference to them.) Many routines that extract objects from other objects also give you the responsibility of owning a reference to the object, e.g. PyObject_GetAttr() and PyObject_GetItem()....
...object. PyObject *PyObject_GetMemoryView(PyObject *obj) Return a memory-view object from an object that defines the buffer interface. A memory-view object is an extended buffer object that could replace the buffer object (but doesn't have to as that could be kept as a simple 1-d memory-view object). Its C-structure is typedef struct { PyObject_HEAD PyObject *base; Py_buffer view; } PyMemoryViewObject; This is functionally similar to the current buffer object except a reference t...
...objects and data mining. ZSQLCatalog solves several major problems often encountered in Enterprise applications: locks, slow reports, and inconsistent transactions. Most Enterprise applications use tables in a relational database to store data. In ERP5 data is stored instead in Zope's object database. Zope eliminates the need for storage adapters or attribute mappings by providing transparent persistence of Python objects. Zope also speeds up object access: Reading the Zope object database is 10...
...object is created, and this attribute must contain the selected size. Therefore, None is not a legal value for this attribute. Hashing objects require the following methods: copy() Return a separate copy of this hashing object. An update to this copy won't affect the original object. digest() Return the hash value of this hashing object as a string containing 8-bit data. The object is not altered in any way by this function; you can continue updating the object after calling this functi...
...object is deleted -- if the assert fails, someone DECREF'ed their reference to the object without releasing it. (The rule should be that you must own a reference to the object while you've acquired the object.) For strings that might be impractical because the string object would have to grow 4 bytes to hold the counter; but the new bytes object (PEP 296) could easily implement the counter, and the array object too -- that way there will be plenty of opportunity to test proper use of the protoc...
...objects will be used for holding character data. The bytes object will fulfil the role of a byte container. Eventually the unicode type will be renamed to str and the old str type will be removed. Specification A bytes object stores a mutable sequence of integers that are in the range 0 to 255. Unlike string objects, indexing a bytes object returns an integer. Assigning or comparing an object that is not an integer to an element causes a TypeError exception. Assigning an element to a value...
...Object attributes and methods) For databases that do not have cursors and for simple applications that do not require the complexity of a cursor, a Connection Object should respond to each of the attributes and methods of the Cursor Object. Databases that have cursor can implement this by using an implicit, internal cursor. Cursor Objects These objects represent a database cursor, which is used to manage the context of a fetch operation. Cursor Objects should respond to the following methods...
...object is returned; a reference to an existing object is fine too. The return value should always be a new reference, owned by the caller. Once the tp_new slot has returned an object, further initialization is attempted by calling the tp_init() slot of the resulting object's type, if not NULL. This has the following signature: int tp_init(PyObject *self, PyObject *args, PyObject *kwds) It corresponds more closely to the __init__() method of classic classes, and in fac...
...object's starting state, as if obj.update(string) was called. After creating a hashing object, arbitrary bytes can be fed into the object using its update() method, and the hash value can be obtained at any time by calling the object's digest() method. Although the parameter is called 'string', hashing objects operate on 8-bit data only. Both 'key' and 'string' must be a bytes-like object (bytes, bytearray...). A hashing object may support one-dimensional, contiguous buffers as argument, too. Te...
...object. If the object is str or bytes, then allow it to pass through with an incremented refcount. If the object defines __fspath__(), then return the result of that method. All other types raise a TypeError. */ PyObject * PyOS_FSPath(PyObject *path) { _Py_IDENTIFIER(__fspath__); PyObject *func = NULL; PyObject *path_repr = NULL; if (PyUnicode_Check(path) || PyBytes_Check(path)) { Py_INCREF(path); return path; } func = _PyObject_LookupSpecia...
...object can behave like an integer. It is not possible to use the nb_int (and __int__ special method) for this purpose because that method is used to coerce objects to integers. It would be inappropriate to allow every object that can be coerced to an integer to be used as an integer everywhere Python expects a true integer. For example, if __int__ were used to convert an object to an integer in slicing, then float objects would be allowed in slicing and x[3.2:5.8] would not raise an error as i...