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xpcom/glue/nsCategoryCache.cpp@97036ab72558 (annotated)

xpcom/glue/nsCategoryCache.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Tue, 06 Jan 2015 21:39:09 +0100

branch

TOR_BUG_9701

changeset 8

97036ab72558

permissions

-rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	/* vim:set st=2 sts=2 ts=2 et cin: */
michael@0	2	/* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	3	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	4	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	5
michael@0	6	#include "nsIObserverService.h"
michael@0	7	#include "mozilla/Services.h"
michael@0	8	#include "nsISupportsPrimitives.h"
michael@0	9	#include "nsIStringEnumerator.h"
michael@0	10
michael@0	11	#include "nsXPCOMCID.h"
michael@0	12
michael@0	13	#include "nsCategoryCache.h"
michael@0	14
michael@0	15	nsCategoryObserver::nsCategoryObserver(const char* aCategory)
michael@0	16	: mCategory(aCategory)
michael@0	17	, mObserversRemoved(false)
michael@0	18	{
michael@0	19	// First, enumerate the currently existing entries
michael@0	20	nsCOMPtr<nsICategoryManager> catMan =
michael@0	21	do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
michael@0	22	if (!catMan)
michael@0	23	return;
michael@0	24
michael@0	25	nsCOMPtr<nsISimpleEnumerator> enumerator;
michael@0	26	nsresult rv = catMan->EnumerateCategory(aCategory,
michael@0	27	getter_AddRefs(enumerator));
michael@0	28	if (NS_FAILED(rv))
michael@0	29	return;
michael@0	30
michael@0	31	nsCOMPtr<nsIUTF8StringEnumerator> strings = do_QueryInterface(enumerator);
michael@0	32	MOZ_ASSERT(strings);
michael@0	33
michael@0	34	bool more;
michael@0	35	while (NS_SUCCEEDED(strings->HasMore(&more)) && more) {
michael@0	36	nsAutoCString entryName;
michael@0	37	strings->GetNext(entryName);
michael@0	38
michael@0	39	nsCString entryValue;
michael@0	40	rv = catMan->GetCategoryEntry(aCategory,
michael@0	41	entryName.get(),
michael@0	42	getter_Copies(entryValue));
michael@0	43	if (NS_SUCCEEDED(rv)) {
michael@0	44	nsCOMPtr<nsISupports> service = do_GetService(entryValue.get());
michael@0	45	if (service) {
michael@0	46	mHash.Put(entryName, service);
michael@0	47	}
michael@0	48	}
michael@0	49	}
michael@0	50
michael@0	51	// Now, listen for changes
michael@0	52	nsCOMPtr<nsIObserverService> serv =
michael@0	53	mozilla::services::GetObserverService();
michael@0	54	if (serv) {
michael@0	55	serv->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
michael@0	56	serv->AddObserver(this, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID, false);
michael@0	57	serv->AddObserver(this, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID, false);
michael@0	58	serv->AddObserver(this, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID, false);
michael@0	59	}
michael@0	60	}
michael@0	61
michael@0	62	nsCategoryObserver::~nsCategoryObserver() {
michael@0	63	}
michael@0	64
michael@0	65	NS_IMPL_ISUPPORTS(nsCategoryObserver, nsIObserver)
michael@0	66
michael@0	67	void
michael@0	68	nsCategoryObserver::ListenerDied() {
michael@0	69	RemoveObservers();
michael@0	70	}
michael@0	71
michael@0	72	void
michael@0	73	nsCategoryObserver::RemoveObservers() {
michael@0	74	if (mObserversRemoved)
michael@0	75	return;
michael@0	76
michael@0	77	mObserversRemoved = true;
michael@0	78	nsCOMPtr<nsIObserverService> obsSvc =
michael@0	79	mozilla::services::GetObserverService();
michael@0	80	if (obsSvc) {
michael@0	81	obsSvc->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
michael@0	82	obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID);
michael@0	83	obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID);
michael@0	84	obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID);
michael@0	85	}
michael@0	86	}
michael@0	87
michael@0	88	NS_IMETHODIMP
michael@0	89	nsCategoryObserver::Observe(nsISupports* aSubject, const char* aTopic,
michael@0	90	const char16_t* aData) {
michael@0	91	if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
michael@0	92	mHash.Clear();
michael@0	93	RemoveObservers();
michael@0	94
michael@0	95	return NS_OK;
michael@0	96	}
michael@0	97
michael@0	98	if (!aData ||
michael@0	99	!nsDependentString(aData).Equals(NS_ConvertASCIItoUTF16(mCategory)))
michael@0	100	return NS_OK;
michael@0	101
michael@0	102	nsAutoCString str;
michael@0	103	nsCOMPtr<nsISupportsCString> strWrapper(do_QueryInterface(aSubject));
michael@0	104	if (strWrapper)
michael@0	105	strWrapper->GetData(str);
michael@0	106
michael@0	107	if (strcmp(aTopic, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID) == 0) {
michael@0	108	// We may get an add notification even when we already have an entry. This
michael@0	109	// is due to the notification happening asynchronously, so if the entry gets
michael@0	110	// added and an nsCategoryObserver gets instantiated before events get
michael@0	111	// processed, we'd get the notification for an existing entry.
michael@0	112	// Do nothing in that case.
michael@0	113	if (mHash.GetWeak(str))
michael@0	114	return NS_OK;
michael@0	115
michael@0	116	nsCOMPtr<nsICategoryManager> catMan =
michael@0	117	do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
michael@0	118	if (!catMan)
michael@0	119	return NS_OK;
michael@0	120
michael@0	121	nsCString entryValue;
michael@0	122	catMan->GetCategoryEntry(mCategory.get(),
michael@0	123	str.get(),
michael@0	124	getter_Copies(entryValue));
michael@0	125
michael@0	126	nsCOMPtr<nsISupports> service = do_GetService(entryValue.get());
michael@0	127
michael@0	128	if (service) {
michael@0	129	mHash.Put(str, service);
michael@0	130	}
michael@0	131	} else if (strcmp(aTopic, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID) == 0) {
michael@0	132	mHash.Remove(str);
michael@0	133	} else if (strcmp(aTopic, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID) == 0) {
michael@0	134	mHash.Clear();
michael@0	135	}
michael@0	136	return NS_OK;
michael@0	137	}