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Diffstat (limited to '')
| -rw-r--r-- | src/libs/xpcom18a4/python/src/PyGBase.cpp | 852 |
1 files changed, 852 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/python/src/PyGBase.cpp b/src/libs/xpcom18a4/python/src/PyGBase.cpp new file mode 100644 index 00000000..e73b2a6d --- /dev/null +++ b/src/libs/xpcom18a4/python/src/PyGBase.cpp @@ -0,0 +1,852 @@ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is the Python XPCOM language bindings. + * + * The Initial Developer of the Original Code is + * ActiveState Tool Corp. + * Portions created by the Initial Developer are Copyright (C) 2000 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Mark Hammond <mhammond@skippinet.com.au> (original author) + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +// PyGBase.cpp - implementation of the PyG_Base class +// +// This code is part of the XPCOM extensions for Python. +// +// Written May 2000 by Mark Hammond. +// +// Based heavily on the Python COM support, which is +// (c) Mark Hammond and Greg Stein. +// +// (c) 2000, ActiveState corp. + +#include "PyXPCOM_std.h" +#include <nsIModule.h> +#include <nsIComponentLoader.h> +#include <nsIInputStream.h> + +static PRInt32 cGateways = 0; +PRInt32 _PyXPCOM_GetGatewayCount(void) +{ + return cGateways; +} + +extern PyG_Base *MakePyG_nsIModule(PyObject *); +extern PyG_Base *MakePyG_nsIComponentLoader(PyObject *instance); +extern PyG_Base *MakePyG_nsIInputStream(PyObject *instance); + +static char *PyXPCOM_szDefaultGatewayAttributeName = (char*)"_com_instance_default_gateway_"; +PyG_Base *GetDefaultGateway(PyObject *instance); +void AddDefaultGateway(PyObject *instance, nsISupports *gateway); +PRBool CheckDefaultGateway(PyObject *real_inst, REFNSIID iid, nsISupports **ret_gateway); + +/*static*/ nsresult +PyG_Base::CreateNew(PyObject *pPyInstance, const nsIID &iid, void **ppResult) +{ + NS_PRECONDITION(ppResult && *ppResult==NULL, "NULL or uninitialized pointer"); + if (ppResult==nsnull) + return NS_ERROR_NULL_POINTER; + + PyG_Base *ret; + // Hack for few extra gateways we support. + if (iid.Equals(NS_GET_IID(nsIModule))) + ret = MakePyG_nsIModule(pPyInstance); + else if (iid.Equals(NS_GET_IID(nsIComponentLoader))) + ret = MakePyG_nsIComponentLoader(pPyInstance); + else if (iid.Equals(NS_GET_IID(nsIInputStream))) + ret = MakePyG_nsIInputStream(pPyInstance); + else + ret = new PyXPCOM_XPTStub(pPyInstance, iid); + if (ret==nsnull) + return NS_ERROR_OUT_OF_MEMORY; + ret->AddRef(); // The first reference for the caller. + *ppResult = ret->ThisAsIID(iid); + NS_ABORT_IF_FALSE(*ppResult != NULL, "ThisAsIID() gave NULL, but we know it supports it!"); + return *ppResult ? NS_OK : NS_ERROR_FAILURE; +} + +PyG_Base::PyG_Base(PyObject *instance, const nsIID &iid) +{ + // Note that "instance" is the _policy_ instance!! + PR_AtomicIncrement(&cGateways); + m_pBaseObject = GetDefaultGateway(instance); + // m_pWeakRef is an nsCOMPtr and needs no init. + + NS_ABORT_IF_FALSE(!(iid.Equals(NS_GET_IID(nsISupportsWeakReference)) || iid.Equals(NS_GET_IID(nsIWeakReference))),"Should not be creating gateways with weak-ref interfaces"); + m_iid = iid; + m_pPyObject = instance; + NS_PRECONDITION(instance, "NULL PyObject for PyXPCOM_XPTStub!"); + +#ifdef NS_BUILD_REFCNT_LOGGING + // If XPCOM reference count logging is enabled, then allow us to give the Python class. + PyObject *realInstance = PyObject_GetAttrString(instance, "_obj_"); + PyObject *r = PyObject_Repr(realInstance); + const char *szRepr; + if (r==NULL) { + PyXPCOM_LogError("Getting the __repr__ of the object failed"); + PyErr_Clear(); + szRepr = "(repr failed!)"; + } + else +#if PY_MAJOR_VERSION <= 2 + szRepr = PyString_AsString(r); +#else + szRepr = PyUnicode_AsUTF8(r); +#endif + if (szRepr==NULL) szRepr = ""; + int reprOffset = *szRepr=='<' ? 1 : 0; + static const char *reprPrefix = "component:"; + if (strncmp(reprPrefix, szRepr+reprOffset, strlen(reprPrefix)) == 0) + reprOffset += strlen(reprPrefix); + strncpy(refcntLogRepr, szRepr + reprOffset, sizeof(refcntLogRepr)-1); + refcntLogRepr[sizeof(refcntLogRepr)-1] = '\0'; + // See if we should get rid of the " at 0x12345" portion. + char *lastPos = strstr(refcntLogRepr, " at "); + if (lastPos) *lastPos = '\0'; + Py_XDECREF(realInstance); + Py_XDECREF(r); +#endif // NS_BUILD_REFCNT_LOGGING + +#ifdef DEBUG_LIFETIMES + { + char *iid_repr; + nsCOMPtr<nsIInterfaceInfoManager> iim = XPTI_GetInterfaceInfoManager(); + if (iim!=nsnull) + iim->GetNameForIID(&iid, &iid_repr); + PyObject *real_instance = PyObject_GetAttrString(instance, "_obj_"); + PyObject *real_repr = PyObject_Repr(real_instance); + + PYXPCOM_LOG_DEBUG("PyG_Base created at %p\n instance_repr=%s\n IID=%s\n", this, PyString_AsString(real_repr), iid_repr); + nsMemory::Free(iid_repr); + Py_XDECREF(real_instance); + Py_XDECREF(real_repr); + } +#endif // DEBUG_LIFETIMES + Py_XINCREF(instance); // instance should never be NULL - but whats an X between friends! + + PyXPCOM_DLLAddRef(); + +#ifdef DEBUG_FULL + LogF("PyGatewayBase: created %s", m_pPyObject ? PyXPCOM_ObTypeName(m_pPyObject) : "<NULL>"); +#endif +} + +PyG_Base::~PyG_Base() +{ + PR_AtomicDecrement(&cGateways); +#ifdef DEBUG_LIFETIMES + PYXPCOM_LOG_DEBUG("PyG_Base: deleted %p", this); +#endif + if ( m_pPyObject ) { + CEnterLeavePython celp; + Py_DECREF(m_pPyObject); + } + if (m_pBaseObject) + m_pBaseObject->Release(); + if (m_pWeakRef) { + // Need to ensure some other thread isnt doing a QueryReferent on + // our weak reference at the same time + CEnterLeaveXPCOMFramework _celf; + PyXPCOM_GatewayWeakReference *p = (PyXPCOM_GatewayWeakReference *)(nsISupports *)m_pWeakRef; + p->m_pBase = nsnull; + m_pWeakRef = nsnull; + } + PyXPCOM_DLLRelease(); +} + +// Get the correct interface pointer for this object given the IID. +void *PyG_Base::ThisAsIID( const nsIID &iid ) +{ + if (this==NULL) return NULL; + if (iid.Equals(NS_GET_IID(nsISupports))) + return (nsISupports *)(nsIInternalPython *)this; + if (iid.Equals(NS_GET_IID(nsISupportsWeakReference))) + return (nsISupportsWeakReference *)this; + if (iid.Equals(NS_GET_IID(nsIInternalPython))) + return (nsISupports *)(nsIInternalPython *)this; + return NULL; +} + +// Call back into Python, passing a Python instance, and get back +// an interface object that wraps the instance. +/*static*/ PRBool +PyG_Base::AutoWrapPythonInstance(PyObject *ob, const nsIID &iid, nsISupports **ppret) +{ + NS_PRECONDITION(ppret!=NULL, "null pointer when wrapping a Python instance!"); + NS_PRECONDITION(ob && PyObject_HasAttrString(ob, "__class__"), + "AutoWrapPythonInstance is expecting an non-NULL instance!"); + PRBool ok = PR_FALSE; + // XXX - todo - this static object leaks! (but Python on Windows leaks 2000+ objects as it is ;-) + static PyObject *func = NULL; // fetch this once and remember! + PyObject *obIID = NULL; + PyObject *wrap_ret = NULL; + PyObject *args = NULL; + if (func==NULL) { // not thread-safe, but nothing bad can happen, except an extra reference leak + PyObject *mod = PyImport_ImportModule("xpcom.server"); + if (mod) + func = PyObject_GetAttrString(mod, "WrapObject"); + Py_XDECREF(mod); + if (func==NULL) goto done; + } + // See if the instance has previously been wrapped. + if (CheckDefaultGateway(ob, iid, ppret)) { + ok = PR_TRUE; // life is good! + } else { + PyErr_Clear(); + + obIID = Py_nsIID::PyObjectFromIID(iid); + if (obIID==NULL) goto done; + args = Py_BuildValue("OOzi", ob, obIID, NULL, 0); + if (args==NULL) goto done; + wrap_ret = PyEval_CallObject(func, args); + if (wrap_ret==NULL) goto done; + ok = Py_nsISupports::InterfaceFromPyObject(wrap_ret, iid, ppret, PR_FALSE, PR_FALSE); +#ifdef DEBUG + if (ok) + // Check we _now_ have a default gateway + { + nsISupports *temp = NULL; + NS_ABORT_IF_FALSE(CheckDefaultGateway(ob, iid, &temp), "Auto-wrapped object didnt get a default gateway!"); + if (temp) temp->Release(); + } +#endif + } +done: +// Py_XDECREF(func); -- func is static for performance reasons. + Py_XDECREF(obIID); + Py_XDECREF(wrap_ret); + Py_XDECREF(args); + return ok; +} + +// Call back into Python, passing a raw nsIInterface object, getting back +// the object to actually use as the gateway parameter for this interface. +// For example, it is expected that the policy will wrap the interface +// object in one of the xpcom.client.Interface objects, allowing +// natural usage of the interface from Python clients. +// Note that piid will usually be NULL - this is because the runtime +// reflection interfaces dont provide this information to me. +// In this case, the Python code may choose to lookup the complete +// interface info to obtain the IID. +// It is expected (but should not be assumed) that the method info +// or the IID will be NULL. +// Worst case, the code should provide a wrapper for the nsiSupports interface, +// so at least the user can simply QI the object. +PyObject * +PyG_Base::MakeInterfaceParam(nsISupports *pis, + const nsIID *piid, + int methodIndex /* = -1 */, + const XPTParamDescriptor *d /* = NULL */, + int paramIndex /* = -1 */) +{ + if (pis==NULL) { + Py_INCREF(Py_None); + return Py_None; + } + // This condition is true today, but not necessarily so. + // But if it ever triggers, the poor Python code has no real hope + // of returning something useful, so we should at least do our + // best to provide the useful data. + NS_WARN_IF_FALSE( ((piid != NULL) ^ (d != NULL)) == 1, "No information on the interface available - Python's gunna have a hard time doing much with it!"); + PyObject *obIID = NULL; + PyObject *obISupports = NULL; + PyObject *obParamDesc = NULL; + PyObject *result = NULL; + + // get the basic interface first, as if we fail, we can try and use this. + // If we don't know the IID, we must explicitly query for nsISupports. + nsCOMPtr<nsISupports> piswrap; + nsIID iid_check; + if (piid) { + iid_check = *piid; + piswrap = pis; + } else { + /* HACK ALERT! Dropping the python interpreter lock here while + doing QueryInterface because it may involve IPC to a python + object in the same interpreter and deadlock. Not at all + sure if this is a good idea or not for the internal PyXPCOM + state, but it might fix the deadloock... Hoping for the best. */ + Py_BEGIN_ALLOW_THREADS; + iid_check = NS_GET_IID(nsISupports); + pis->QueryInterface(iid_check, getter_AddRefs(piswrap)); + Py_END_ALLOW_THREADS; + } + + obISupports = Py_nsISupports::PyObjectFromInterface(piswrap, iid_check, PR_FALSE); + if (!obISupports) + goto done; + if (piid==NULL) { + obIID = Py_None; + Py_INCREF(Py_None); + } else + obIID = Py_nsIID::PyObjectFromIID(*piid); + if (obIID==NULL) + goto done; + obParamDesc = PyObject_FromXPTParamDescriptor(d); + if (obParamDesc==NULL) + goto done; + + result = PyObject_CallMethod(m_pPyObject, + (char*)"_MakeInterfaceParam_", + (char*)"OOiOi", + obISupports, + obIID, + methodIndex, + obParamDesc, + paramIndex); +done: + if (PyErr_Occurred()) { + NS_WARN_IF_FALSE(result==NULL, "Have an error, but also a result!"); + PyXPCOM_LogError("Wrapping an interface object for the gateway failed\n"); + } + Py_XDECREF(obIID); + Py_XDECREF(obParamDesc); + if (result==NULL) { // we had an error. + PyErr_Clear(); // but are not reporting it back to Python itself! + // return our obISupports. If NULL, we are really hosed and nothing we can do. + return obISupports; + } + // Dont need to return this - we have a better result. + Py_XDECREF(obISupports); + return result; +} + +NS_IMETHODIMP +PyG_Base::QueryInterface(REFNSIID iid, void** ppv) +{ +#ifdef PYXPCOM_DEBUG_FULL + { + char *sziid = iid.ToString(); + LogF("PyGatewayBase::QueryInterface: %s", sziid); + Allocator::Free(sziid); + } +#endif + NS_PRECONDITION(ppv, "NULL pointer"); + if (ppv==nsnull) + return NS_ERROR_NULL_POINTER; + *ppv = nsnull; + // If one of our native interfaces (but NOT nsISupports if we have a base) + // return this. + // It is important is that nsISupports come from the base object + // to ensure that we live by XPCOM identity rules (other interfaces need + // not abide by this rule - only nsISupports.) + if ( (m_pBaseObject==NULL || !iid.Equals(NS_GET_IID(nsISupports))) + && (*ppv=ThisAsIID(iid)) != NULL ) { + AddRef(); + return NS_OK; + } + // If we have a "base object", then we need to delegate _every_ remaining + // QI to it. + if (m_pBaseObject != NULL) + return m_pBaseObject->QueryInterface(iid, ppv); + + // Call the Python policy to see if it (says it) supports the interface + PRBool supports = PR_FALSE; + { // temp scope for Python lock + CEnterLeavePython celp; + + PyObject * ob = Py_nsIID::PyObjectFromIID(iid); + // must say this is an 'internal' call, else we recurse QI into + // oblivion. + PyObject * this_interface_ob = Py_nsISupports::PyObjectFromInterface( + (nsXPTCStubBase *)this, + iid, PR_FALSE, PR_TRUE); + if ( !ob || !this_interface_ob) { + Py_XDECREF(ob); + Py_XDECREF(this_interface_ob); + return NS_ERROR_OUT_OF_MEMORY; + } + + PyObject *result = PyObject_CallMethod(m_pPyObject, (char*)"_QueryInterface_", + (char*)"OO", + this_interface_ob, ob); + Py_DECREF(ob); + Py_DECREF(this_interface_ob); + + if ( result ) { + if (Py_nsISupports::InterfaceFromPyObject(result, iid, (nsISupports **)ppv, PR_TRUE)) { + // If OK, but NULL, _QI_ returned None, which simply means + // "no such interface" + supports = (*ppv!=NULL); + // result has been QI'd and AddRef'd all ready for return. + } else { + // Dump this message and any Python exception before + // reporting the fact that QI failed - this error + // may provide clues! + PyXPCOM_LogError("The _QueryInterface_ method returned an object of type '%s', but an interface was expected\n", PyXPCOM_ObTypeName(result)); + // supports remains false + } + Py_DECREF(result); + } else { + NS_ABORT_IF_FALSE(PyErr_Occurred(), "Got NULL result, but no Python error flagged!"); + NS_WARN_IF_FALSE(!supports, "Have failure with success flag set!"); + PyXPCOM_LogError("The _QueryInterface_ processing failed.\n"); + // supports remains false. + // We have reported the error, and are returning to COM, + // so we should clear it. + PyErr_Clear(); + } + } // end of temp scope for Python lock - lock released here! + if ( !supports ) + return NS_ERROR_NO_INTERFACE; + return NS_OK; +} + +nsrefcnt +PyG_Base::AddRef(void) +{ + nsrefcnt cnt = (nsrefcnt) PR_AtomicIncrement((PRInt32*)&mRefCnt); +#ifdef NS_BUILD_REFCNT_LOGGING + // If we have no pBaseObject, then we need to ignore them + if (m_pBaseObject == NULL) + NS_LOG_ADDREF(this, cnt, refcntLogRepr, sizeof(*this)); +#endif + return cnt; +} + +nsrefcnt +PyG_Base::Release(void) +{ + nsrefcnt cnt = (nsrefcnt) PR_AtomicDecrement((PRInt32*)&mRefCnt); +#ifdef NS_BUILD_REFCNT_LOGGING + if (m_pBaseObject == NULL) + NS_LOG_RELEASE(this, cnt, refcntLogRepr); +#endif + if ( cnt == 0 ) + delete this; + return cnt; +} + +NS_IMETHODIMP +PyG_Base::GetWeakReference(nsIWeakReference **ret) +{ + // always delegate back to the "base" gateway for the object, as this tear-off + // interface may not live as long as the base. So we recurse back to the base. + if (m_pBaseObject) { + NS_PRECONDITION(m_pWeakRef == nsnull, "Not a base object, but do have a weak-ref!"); + return m_pBaseObject->GetWeakReference(ret); + } + NS_PRECONDITION(ret, "null pointer"); + if (ret==nsnull) return NS_ERROR_INVALID_POINTER; + if (!m_pWeakRef) { + // First query for a weak reference - create it. + // XXX - this looks like it needs thread safety!? + m_pWeakRef = new PyXPCOM_GatewayWeakReference(this); + NS_ABORT_IF_FALSE(m_pWeakRef, "Shouldn't be able to fail creating a weak reference!"); + if (!m_pWeakRef) + return NS_ERROR_UNEXPECTED; + } + *ret = m_pWeakRef; + (*ret)->AddRef(); + return NS_OK; +} + +nsresult PyG_Base::HandleNativeGatewayError(const char *szMethodName) +{ + nsresult rc = NS_OK; + if (PyErr_Occurred()) { + // The error handling - fairly involved, but worth it as + // good error reporting is critical for users to know WTF + // is going on - especially with TypeErrors etc in their + // return values (ie, after the Python code has successfully + // exited, but we encountered errors unpacking their + // result values for the COM caller - there is literally no + // way to catch these exceptions from Python code, as their + // is no Python function directly on the call-stack) + + // First line of attack in an error is to call-back on the policy. + // If the callback of the error handler succeeds and returns an + // integer (for the nsresult), we take no further action. + + // If this callback fails, we log _2_ exceptions - the error + // handler error, and the original error. + + PRBool bProcessMainError = PR_TRUE; // set to false if our exception handler does its thing! + PyObject *exc_typ, *exc_val, *exc_tb; + PyErr_Fetch(&exc_typ, &exc_val, &exc_tb); + + PyObject *err_result = PyObject_CallMethod(m_pPyObject, + (char*)"_GatewayException_", + (char*)"z(OOO)", + szMethodName, + exc_typ ? exc_typ : Py_None, // should never be NULL, but defensive programming... + exc_val ? exc_val : Py_None, // may well be NULL. + exc_tb ? exc_tb : Py_None); // may well be NULL. + if (err_result == NULL) { + PyXPCOM_LogError("The exception handler _CallMethodException_ failed!\n"); + } else if (err_result == Py_None) { + // The exception handler has chosen not to do anything with + // this error, so we still need to print it! + ; + } else if (PyInt_Check(err_result)) { + // The exception handler has given us the nresult. + rc = PyInt_AsLong(err_result); + bProcessMainError = PR_FALSE; + } else { + // The exception handler succeeded, but returned other than + // int or None. + PyXPCOM_LogError("The _CallMethodException_ handler returned object of type '%s' - None or an integer expected\n", PyXPCOM_ObTypeName(err_result)); + } + Py_XDECREF(err_result); + PyErr_Restore(exc_typ, exc_val, exc_tb); + if (bProcessMainError) { + PyXPCOM_LogError("The function '%s' failed\n", szMethodName); + rc = PyXPCOM_SetCOMErrorFromPyException(); + } + PyErr_Clear(); + } + return rc; +} + +static nsresult do_dispatch( + PyObject *pPyObject, + PyObject **ppResult, + const char *szMethodName, + const char *szFormat, + va_list va + ) +{ + NS_PRECONDITION(ppResult, "Must provide a result buffer"); + *ppResult = nsnull; + // Build the Invoke arguments... + PyObject *args = NULL; + PyObject *method = NULL; + PyObject *real_ob = NULL; + nsresult ret = NS_ERROR_FAILURE; + if ( szFormat ) + args = Py_VaBuildValue((char *)szFormat, va); + else + args = PyTuple_New(0); + if ( !args ) + goto done; + + // make sure a tuple. + if ( !PyTuple_Check(args) ) { + PyObject *a = PyTuple_New(1); + if ( a == NULL ) + { + Py_DECREF(args); + goto done; + } + PyTuple_SET_ITEM(a, 0, args); + args = a; + } + // Bit to a hack here to maintain the use of a policy. + // We actually get the policies underlying object + // to make the call on. + real_ob = PyObject_GetAttrString(pPyObject, "_obj_"); + if (real_ob == NULL) { + PyErr_Format(PyExc_AttributeError, "The policy object does not have an '_obj_' attribute."); + goto done; + } + method = PyObject_GetAttrString(real_ob, (char *)szMethodName); + if ( !method ) { + PyErr_Clear(); + ret = NS_PYXPCOM_NO_SUCH_METHOD; + goto done; + } + // Make the call + *ppResult = PyEval_CallObject(method, args); + ret = *ppResult ? NS_OK : NS_ERROR_FAILURE; +done: + Py_XDECREF(method); + Py_XDECREF(real_ob); + Py_XDECREF(args); + return ret; +} + + +nsresult PyG_Base::InvokeNativeViaPolicyInternal( + const char *szMethodName, + PyObject **ppResult, + const char *szFormat, + va_list va + ) +{ + if ( m_pPyObject == NULL || szMethodName == NULL ) + return NS_ERROR_NULL_POINTER; + + PyObject *temp = nsnull; + if (ppResult == nsnull) + ppResult = &temp; + nsresult nr = do_dispatch(m_pPyObject, ppResult, szMethodName, szFormat, va); + + // If temp is NULL, they provided a buffer, and we dont touch it. + // If not NULL, *ppResult = temp, and _we_ do own it. + Py_XDECREF(temp); + return nr; +} + +nsresult PyG_Base::InvokeNativeViaPolicy( + const char *szMethodName, + PyObject **ppResult /* = NULL */, + const char *szFormat /* = NULL */, + ... + ) +{ + va_list va; + va_start(va, szFormat); + nsresult nr = InvokeNativeViaPolicyInternal(szMethodName, ppResult, szFormat, va); + va_end(va); + + if (nr == NS_PYXPCOM_NO_SUCH_METHOD) { + // Only problem was missing method. + PyErr_Format(PyExc_AttributeError, "The object does not have a '%s' function.", szMethodName); + } + return nr == NS_OK ? NS_OK : HandleNativeGatewayError(szMethodName); +} + +nsresult PyG_Base::InvokeNativeGetViaPolicy( + const char *szPropertyName, + PyObject **ppResult /* = NULL */ + ) +{ + PyObject *ob_ret = NULL; + nsresult ret = NS_OK; + PyObject *real_ob = NULL; + if ( m_pPyObject == NULL || szPropertyName == NULL ) + return NS_ERROR_NULL_POINTER; + // First see if we have a method of that name. + char buf[256]; + strcpy(buf, "get_"); + strncat(buf, szPropertyName, sizeof(buf)*sizeof(buf[0])-strlen(buf)-1); + buf[sizeof(buf)/sizeof(buf[0])-1] = '\0'; + ret = InvokeNativeViaPolicyInternal(buf, ppResult, nsnull, nsnull); + if (ret == NS_PYXPCOM_NO_SUCH_METHOD) { + // No method of that name - just try a property. + // Bit to a hack here to maintain the use of a policy. + // We actually get the policies underlying object + // to make the call on. + real_ob = PyObject_GetAttrString(m_pPyObject, "_obj_"); + if (real_ob == NULL) { + PyErr_Format(PyExc_AttributeError, "The policy object does not have an '_obj_' attribute."); + ret = HandleNativeGatewayError(szPropertyName); + goto done; + } + ob_ret = PyObject_GetAttrString(real_ob, (char *)szPropertyName); + if (ob_ret==NULL) { + PyErr_Format(PyExc_AttributeError, + "The object does not have a 'get_%s' function, or a '%s attribute.", + szPropertyName, szPropertyName); + } else { + ret = NS_OK; + if (ppResult) + *ppResult = ob_ret; + else + Py_XDECREF(ob_ret); + } + } + if (ret != NS_OK) + ret = HandleNativeGatewayError(szPropertyName); + +done: + Py_XDECREF(real_ob); + return ret; +} + +nsresult PyG_Base::InvokeNativeSetViaPolicy( + const char *szPropertyName, + ... + ) +{ + if ( m_pPyObject == NULL || szPropertyName == NULL ) + return NS_ERROR_NULL_POINTER; + nsresult ret = NS_OK; + PyObject *real_ob = NULL; + char buf[256]; + strcpy(buf, "set_"); + strncat(buf, szPropertyName, sizeof(buf)*sizeof(buf[0])-strlen(buf)-1); + buf[sizeof(buf)/sizeof(buf[0])-1] = '\0'; + va_list va; + va_start(va, szPropertyName); + ret = InvokeNativeViaPolicyInternal(buf, NULL, "O", va); + va_end(va); + if (ret == NS_PYXPCOM_NO_SUCH_METHOD) { + // No method of that name - just try a property. + // Bit to a hack here to maintain the use of a policy. + // We actually get the policies underlying object + // to make the call on. + real_ob = PyObject_GetAttrString(m_pPyObject, "_obj_"); + if (real_ob == NULL) { + PyErr_Format(PyExc_AttributeError, "The policy object does not have an '_obj_' attribute."); + ret = HandleNativeGatewayError(szPropertyName); + goto done; + } + va_list va2; + va_start(va2, szPropertyName); + PyObject *arg = va_arg( va2, PyObject *); + va_end(va2); + if (PyObject_SetAttrString(real_ob, (char *)szPropertyName, arg) == 0) + ret = NS_OK; + else { + PyErr_Format(PyExc_AttributeError, + "The object does not have a 'set_%s' function, or a '%s attribute.", + szPropertyName, szPropertyName); + } + } + if (ret != NS_OK) + ret = HandleNativeGatewayError(szPropertyName); +done: + Py_XDECREF(real_ob); + return ret; +} + +// Get at the underlying Python object. +PyObject *PyG_Base::UnwrapPythonObject(void) +{ + Py_INCREF(m_pPyObject); + return m_pPyObject; +} +/****************************************************** + + Some special support to help with object identity. + + In the simplest case, assume a Python XPCOM object is + supporting a function "nsIWhatever GetWhatever()", + so implements it as: + return self + it is almost certain they intend returning + the same COM OBJECT to the caller! Thus, if a user of this COM + object does: + + p1 = foo.GetWhatever(); + p2 = foo.GetWhatever(); + + We almost certainly expect p1==p2==foo. + + We previously _did_ have special support for the "self" + example above, but this implements a generic scheme that + works for _all_ objects. + + Whenever we are asked to "AutoWrap" a Python object, the + first thing we do is see if it has been auto-wrapped before. + + If not, we create a new wrapper, then make a COM weak reference + to that wrapper, and store it directly back into the instance + we are auto-wrapping! The use of a weak-reference prevents + cycles. + + The existance of this attribute in an instance indicates if it + has been previously auto-wrapped. + + If it _has_ previously been auto-wrapped, we de-reference the + weak reference, and use that gateway. + +*********************************************************************/ + +PyG_Base *GetDefaultGateway(PyObject *policy) +{ + // NOTE: Instance is the policy, not the real instance + PyObject *instance = PyObject_GetAttrString(policy, "_obj_"); + if (instance == nsnull) + return nsnull; + PyObject *ob_existing_weak = PyObject_GetAttrString(instance, PyXPCOM_szDefaultGatewayAttributeName); + Py_DECREF(instance); + if (ob_existing_weak != NULL) { + PRBool ok = PR_TRUE; + nsCOMPtr<nsIWeakReference> pWeakRef; + ok = NS_SUCCEEDED(Py_nsISupports::InterfaceFromPyObject(ob_existing_weak, + NS_GET_IID(nsIWeakReference), + getter_AddRefs(pWeakRef), + PR_FALSE)); + Py_DECREF(ob_existing_weak); + nsISupports *pip; + if (ok) { + nsresult nr = pWeakRef->QueryReferent( NS_GET_IID(nsIInternalPython), (void **)&pip); + if (NS_FAILED(nr)) + return nsnull; + return (PyG_Base *)(nsIInternalPython *)pip; + } + } else + PyErr_Clear(); + return nsnull; +} + +PRBool CheckDefaultGateway(PyObject *real_inst, REFNSIID iid, nsISupports **ret_gateway) +{ + NS_ABORT_IF_FALSE(real_inst, "Did not have an _obj_ attribute"); + if (real_inst==NULL) { + PyErr_Clear(); + return PR_FALSE; + } + PyObject *ob_existing_weak = PyObject_GetAttrString(real_inst, PyXPCOM_szDefaultGatewayAttributeName); + if (ob_existing_weak != NULL) { + // We have an existing default, but as it is a weak reference, it + // may no longer be valid. Check it. + PRBool ok = PR_TRUE; + nsCOMPtr<nsIWeakReference> pWeakRef; + ok = NS_SUCCEEDED(Py_nsISupports::InterfaceFromPyObject(ob_existing_weak, + NS_GET_IID(nsIWeakReference), + getter_AddRefs(pWeakRef), + PR_FALSE)); + Py_DECREF(ob_existing_weak); + if (ok) { + Py_BEGIN_ALLOW_THREADS; + ok = NS_SUCCEEDED(pWeakRef->QueryReferent( iid, (void **)(ret_gateway))); + Py_END_ALLOW_THREADS; + } + if (!ok) { + // We have the attribute, but not valid - wipe it + // before restoring it. + if (0 != PyObject_DelAttrString(real_inst, PyXPCOM_szDefaultGatewayAttributeName)) + PyErr_Clear(); + } + return ok; + } + PyErr_Clear(); + return PR_FALSE; +} + +void AddDefaultGateway(PyObject *instance, nsISupports *gateway) +{ + // NOTE: Instance is the _policy_! + PyObject *real_inst = PyObject_GetAttrString(instance, "_obj_"); + NS_ABORT_IF_FALSE(real_inst, "Could not get the '_obj_' element"); + if (!real_inst) return; + if (!PyObject_HasAttrString(real_inst, PyXPCOM_szDefaultGatewayAttributeName)) { + nsCOMPtr<nsISupportsWeakReference> swr( do_QueryInterface((nsISupportsWeakReference *)(gateway)) ); + NS_ABORT_IF_FALSE(swr, "Our gateway failed with a weak reference query"); + // Create the new default gateway - get a weak reference for our gateway. + if (swr) { + nsCOMPtr<nsIWeakReference> pWeakReference; + swr->GetWeakReference( getter_AddRefs(pWeakReference) ); + if (pWeakReference) { + PyObject *ob_new_weak = Py_nsISupports::PyObjectFromInterface(pWeakReference, + NS_GET_IID(nsIWeakReference), + PR_FALSE ); /* bMakeNicePyObject */ + // pWeakReference reference consumed. + if (ob_new_weak) { + PyObject_SetAttrString(real_inst, PyXPCOM_szDefaultGatewayAttributeName, ob_new_weak); + Py_DECREF(ob_new_weak); + } + } + } + } + Py_DECREF(real_inst); +} |