esp-idf/components/nvs_flash/src/nvs_pagemanager.cpp

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// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "nvs_pagemanager.hpp"
namespace nvs
{
esp_err_t PageManager::load(uint32_t baseSector, uint32_t sectorCount)
{
mBaseSector = baseSector;
mPageCount = sectorCount;
mPageList.clear();
mFreePageList.clear();
mPages.reset(new Page[sectorCount]);
for (uint32_t i = 0; i < sectorCount; ++i) {
auto err = mPages[i].load(baseSector + i);
if (err != ESP_OK) {
return err;
}
uint32_t seqNumber;
if (mPages[i].getSeqNumber(seqNumber) != ESP_OK) {
mFreePageList.push_back(&mPages[i]);
} else {
auto pos = std::find_if(std::begin(mPageList), std::end(mPageList), [=](const Page& page) -> bool {
uint32_t otherSeqNumber;
return page.getSeqNumber(otherSeqNumber) == ESP_OK && otherSeqNumber > seqNumber;
});
if (pos == mPageList.end()) {
mPageList.push_back(&mPages[i]);
} else {
mPageList.insert(pos, &mPages[i]);
}
}
}
if (mPageList.empty()) {
mSeqNumber = 0;
return activatePage();
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} else {
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uint32_t lastSeqNo;
ESP_ERROR_CHECK( mPageList.back().getSeqNumber(lastSeqNo) );
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mSeqNumber = lastSeqNo + 1;
}
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// if power went out after a new item for the given key was written,
// but before the old one was erased, we end up with a duplicate item
Page& lastPage = back();
size_t lastItemIndex = SIZE_MAX;
Item item;
size_t itemIndex = 0;
while (lastPage.findItem(Page::NS_ANY, ItemType::ANY, nullptr, itemIndex, item) == ESP_OK) {
itemIndex += item.span;
lastItemIndex = itemIndex;
}
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if (lastItemIndex != SIZE_MAX) {
auto last = PageManager::TPageListIterator(&lastPage);
for (auto it = begin(); it != last; ++it) {
if (it->eraseItem(item.nsIndex, item.datatype, item.key) == ESP_OK) {
break;
}
}
}
// check if power went out while page was being freed
for (auto it = begin(); it!= end(); ++it) {
if (it->state() == Page::PageState::FREEING) {
Page* newPage = &mPageList.back();
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if (newPage->state() != Page::PageState::ACTIVE) {
auto err = activatePage();
if (err != ESP_OK) {
return err;
}
newPage = &mPageList.back();
}
while (true) {
auto err = it->moveItem(*newPage);
if (err == ESP_ERR_NVS_NOT_FOUND) {
break;
} else if (err != ESP_OK) {
return err;
}
}
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auto err = it->erase();
if (err != ESP_OK) {
return err;
}
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Page* p = static_cast<Page*>(it);
mPageList.erase(it);
mFreePageList.push_back(p);
break;
}
}
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return ESP_OK;
}
esp_err_t PageManager::requestNewPage()
{
if (mFreePageList.empty()) {
return ESP_ERR_NVS_INVALID_STATE;
}
// do we have at least two free pages? in that case no erasing is required
if (mFreePageList.size() >= 2) {
return activatePage();
}
// find the page with the higest number of erased items
TPageListIterator maxErasedItemsPageIt;
size_t maxErasedItems = 0;
for (auto it = begin(); it != end(); ++it) {
auto erased = it->getErasedEntryCount();
if (erased > maxErasedItems) {
maxErasedItemsPageIt = it;
maxErasedItems = erased;
}
}
if (maxErasedItems == 0) {
return ESP_ERR_NVS_NOT_ENOUGH_SPACE;
}
esp_err_t err = activatePage();
if (err != ESP_OK) {
return err;
}
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Page* newPage = &mPageList.back();
Page* erasedPage = maxErasedItemsPageIt;
#ifndef NDEBUG
size_t usedEntries = erasedPage->getUsedEntryCount();
#endif
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err = erasedPage->markFreeing();
if (err != ESP_OK) {
return err;
}
while (true) {
err = erasedPage->moveItem(*newPage);
if (err == ESP_ERR_NVS_NOT_FOUND) {
break;
} else if (err != ESP_OK) {
return err;
}
}
err = erasedPage->erase();
if (err != ESP_OK) {
return err;
}
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#ifndef NDEBUG
assert(usedEntries == newPage->getUsedEntryCount());
#endif
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mPageList.erase(maxErasedItemsPageIt);
mFreePageList.push_back(erasedPage);
return ESP_OK;
}
esp_err_t PageManager::activatePage()
{
if (mFreePageList.empty()) {
return ESP_ERR_NVS_NOT_ENOUGH_SPACE;
}
Page* p = &mFreePageList.front();
if (p->state() == Page::PageState::CORRUPT) {
auto err = p->erase();
if (err != ESP_OK) {
return err;
}
}
mFreePageList.pop_front();
mPageList.push_back(p);
p->setSeqNumber(mSeqNumber);
++mSeqNumber;
return ESP_OK;
}
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} // namespace nvs