gecko-dev/netwerk/cache/nsDiskCacheBinding.cpp

372 lines
11 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/MemoryReporting.h"
#include "nsCache.h"
#include <limits.h>
#include "nscore.h"
#include "nsDiskCacheBinding.h"
#include "nsCacheService.h"
using namespace mozilla;
/******************************************************************************
* static hash table callback functions
*
*****************************************************************************/
struct HashTableEntry : PLDHashEntryHdr {
nsDiskCacheBinding * mBinding;
};
static PLDHashNumber
HashKey(const void *key)
{
return (PLDHashNumber) NS_PTR_TO_INT32(key);
}
static bool
MatchEntry(const PLDHashEntryHdr * header,
const void * key)
{
HashTableEntry * hashEntry = (HashTableEntry *) header;
return (hashEntry->mBinding->mRecord.HashNumber() == (PLDHashNumber) NS_PTR_TO_INT32(key));
}
static void
MoveEntry(PLDHashTable * /* table */,
const PLDHashEntryHdr * src,
PLDHashEntryHdr * dst)
{
((HashTableEntry *)dst)->mBinding = ((HashTableEntry *)src)->mBinding;
}
static void
ClearEntry(PLDHashTable * /* table */,
PLDHashEntryHdr * header)
{
((HashTableEntry *)header)->mBinding = nullptr;
}
/******************************************************************************
* Utility Functions
*****************************************************************************/
nsDiskCacheBinding *
GetCacheEntryBinding(nsCacheEntry * entry)
{
return (nsDiskCacheBinding *) entry->Data();
}
/******************************************************************************
* nsDiskCacheBinding
*****************************************************************************/
NS_IMPL_ISUPPORTS0(nsDiskCacheBinding)
nsDiskCacheBinding::nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record)
: mCacheEntry(entry)
, mStreamIO(nullptr)
, mDeactivateEvent(nullptr)
{
NS_ASSERTION(record->ValidRecord(), "bad record");
PR_INIT_CLIST(this);
mRecord = *record;
mDoomed = entry->IsDoomed();
mGeneration = record->Generation(); // 0 == uninitialized, or data & meta using block files
}
nsDiskCacheBinding::~nsDiskCacheBinding()
{
// Grab the cache lock since the binding is stored in nsCacheEntry::mData
// and it is released using nsCacheService::ReleaseObject_Locked() which
// releases the object outside the cache lock.
nsCacheServiceAutoLock lock;
NS_ASSERTION(PR_CLIST_IS_EMPTY(this), "binding deleted while still on list");
if (!PR_CLIST_IS_EMPTY(this))
PR_REMOVE_LINK(this); // XXX why are we still on a list?
// sever streamIO/binding link
if (mStreamIO) {
if (NS_FAILED(mStreamIO->ClearBinding()))
nsCacheService::DoomEntry(mCacheEntry);
NS_RELEASE(mStreamIO);
}
}
nsresult
nsDiskCacheBinding::EnsureStreamIO()
{
if (!mStreamIO) {
mStreamIO = new nsDiskCacheStreamIO(this);
if (!mStreamIO) return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(mStreamIO);
}
return NS_OK;
}
/******************************************************************************
* nsDiskCacheBindery
*
* Keeps track of bound disk cache entries to detect for collisions.
*
*****************************************************************************/
const PLDHashTableOps nsDiskCacheBindery::ops =
{
HashKey,
MatchEntry,
MoveEntry,
ClearEntry
};
nsDiskCacheBindery::nsDiskCacheBindery()
: table(&ops, sizeof(HashTableEntry), kInitialTableLength)
, initialized(false)
{
}
nsDiskCacheBindery::~nsDiskCacheBindery()
{
Reset();
}
void
nsDiskCacheBindery::Init()
{
table.ClearAndPrepareForLength(kInitialTableLength);
initialized = true;
}
void
nsDiskCacheBindery::Reset()
{
if (initialized) {
table.ClearAndPrepareForLength(kInitialTableLength);
initialized = false;
}
}
nsDiskCacheBinding *
nsDiskCacheBindery::CreateBinding(nsCacheEntry * entry,
nsDiskCacheRecord * record)
{
NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
nsCOMPtr<nsISupports> data = entry->Data();
if (data) {
NS_ERROR("cache entry already has bind data");
return nullptr;
}
nsDiskCacheBinding * binding = new nsDiskCacheBinding(entry, record);
if (!binding) return nullptr;
// give ownership of the binding to the entry
entry->SetData(binding);
// add binding to collision detection system
nsresult rv = AddBinding(binding);
if (NS_FAILED(rv)) {
entry->SetData(nullptr);
return nullptr;
}
return binding;
}
/**
* FindActiveEntry : to find active colliding entry so we can doom it
*/
nsDiskCacheBinding *
nsDiskCacheBindery::FindActiveBinding(uint32_t hashNumber)
{
NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
// find hash entry for key
auto hashEntry = static_cast<HashTableEntry*>
(table.Search((void*)(uintptr_t)hashNumber));
if (!hashEntry) return nullptr;
// walk list looking for active entry
NS_ASSERTION(hashEntry->mBinding, "hash entry left with no binding");
nsDiskCacheBinding * binding = hashEntry->mBinding;
while (binding->mCacheEntry->IsDoomed()) {
binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
if (binding == hashEntry->mBinding) return nullptr;
}
return binding;
}
/**
* AddBinding
*
* Called from FindEntry() if we read an entry off of disk
* - it may already have a generation number
* - a generation number conflict is an error
*
* Called from BindEntry()
* - a generation number needs to be assigned
*/
nsresult
nsDiskCacheBindery::AddBinding(nsDiskCacheBinding * binding)
{
NS_ENSURE_ARG_POINTER(binding);
NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
// find hash entry for key
auto hashEntry = static_cast<HashTableEntry*>
(table.Add((void*)(uintptr_t)binding->mRecord.HashNumber(), fallible));
if (!hashEntry)
return NS_ERROR_OUT_OF_MEMORY;
if (hashEntry->mBinding == nullptr) {
hashEntry->mBinding = binding;
if (binding->mGeneration == 0)
binding->mGeneration = 1; // if generation uninitialized, set it to 1
return NS_OK;
}
// insert binding in generation order
nsDiskCacheBinding * p = hashEntry->mBinding;
bool calcGeneration = (binding->mGeneration == 0); // do we need to calculate generation?
if (calcGeneration) binding->mGeneration = 1; // initialize to 1 if uninitialized
while (1) {
if (binding->mGeneration < p->mGeneration) {
// here we are
PR_INSERT_BEFORE(binding, p);
if (hashEntry->mBinding == p)
hashEntry->mBinding = binding;
break;
}
if (binding->mGeneration == p->mGeneration) {
if (calcGeneration) ++binding->mGeneration; // try the next generation
else {
NS_ERROR("### disk cache: generations collide!");
return NS_ERROR_UNEXPECTED;
}
}
p = (nsDiskCacheBinding *)PR_NEXT_LINK(p);
if (p == hashEntry->mBinding) {
// end of line: insert here or die
p = (nsDiskCacheBinding *)PR_PREV_LINK(p); // back up and check generation
if (p->mGeneration == 255) {
NS_WARNING("### disk cache: generation capacity at full");
return NS_ERROR_UNEXPECTED;
}
PR_INSERT_BEFORE(binding, hashEntry->mBinding);
break;
}
}
return NS_OK;
}
/**
* RemoveBinding : remove binding from collision detection on deactivation
*/
void
nsDiskCacheBindery::RemoveBinding(nsDiskCacheBinding * binding)
{
NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
if (!initialized) return;
void* key = (void *)(uintptr_t)binding->mRecord.HashNumber();
auto hashEntry =
static_cast<HashTableEntry*>(table.Search((void*)(uintptr_t) key));
if (!hashEntry) {
NS_WARNING("### disk cache: binding not in hashtable!");
return;
}
if (binding == hashEntry->mBinding) {
if (PR_CLIST_IS_EMPTY(binding)) {
// remove this hash entry
table.Remove((void*)(uintptr_t) binding->mRecord.HashNumber());
return;
} else {
// promote next binding to head, and unlink this binding
hashEntry->mBinding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
}
}
PR_REMOVE_AND_INIT_LINK(binding);
}
/**
* ActiveBindings: return true if any bindings have open descriptors.
*/
bool
nsDiskCacheBindery::ActiveBindings()
{
NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
if (!initialized) return false;
for (auto iter = table.Iter(); !iter.Done(); iter.Next()) {
auto entry = static_cast<HashTableEntry*>(iter.Get());
nsDiskCacheBinding* binding = entry->mBinding;
nsDiskCacheBinding* head = binding;
do {
if (binding->IsActive()) {
return true;
}
binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
} while (binding != head);
}
return false;
}
/**
* SizeOfExcludingThis: return the amount of heap memory (bytes) being used by
* the bindery.
*/
size_t
nsDiskCacheBindery::SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf)
{
NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
if (!initialized) return 0;
size_t size = 0;
for (auto iter = table.Iter(); !iter.Done(); iter.Next()) {
auto entry = static_cast<HashTableEntry*>(iter.Get());
nsDiskCacheBinding* binding = entry->mBinding;
nsDiskCacheBinding* head = binding;
do {
size += aMallocSizeOf(binding);
if (binding->mStreamIO) {
size += binding->mStreamIO->SizeOfIncludingThis(aMallocSizeOf);
}
// No good way to get at mDeactivateEvent internals for proper
// size, so we use this as an estimate.
if (binding->mDeactivateEvent) {
size += aMallocSizeOf(binding->mDeactivateEvent);
}
binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
} while (binding != head);
}
return size;
}