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// Copyright 2021 The Pigweed Authors
//
// 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
//
// https://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 "pw_persistent_ram/persistent_buffer.h"
#include <cstddef>
#include <span>
#include <type_traits>
#include "gtest/gtest.h"
#include "pw_bytes/span.h"
#include "pw_random/xor_shift.h"
namespace pw::persistent_ram {
namespace {
class PersistentTest : public ::testing::Test {
protected:
static constexpr size_t kBufferSize = 256;
PersistentTest() { ZeroPersistentMemory(); }
// Emulate invalidation of persistent section(s).
void ZeroPersistentMemory() { memset(buffer_, 0, sizeof(buffer_)); }
void RandomFillMemory() {
random::XorShiftStarRng64 rng(0x9ad75);
StatusWithSize sws = rng.Get(buffer_);
ASSERT_TRUE(sws.ok());
ASSERT_EQ(sws.size(), sizeof(buffer_));
}
PersistentBuffer<kBufferSize>& GetPersistentBuffer() {
return *(new (buffer_) PersistentBuffer<kBufferSize>());
}
// Allocate a chunk of aligned storage that can be independently controlled.
alignas(PersistentBuffer<kBufferSize>)
std::byte buffer_[sizeof(PersistentBuffer<kBufferSize>)];
};
TEST_F(PersistentTest, DefaultConstructionAndDestruction) {
constexpr uint32_t kExpectedNumber = 0x6C2C6582;
{
// Emulate a boot where the persistent sections were invalidated.
// Although the fixture always does this, we do this an extra time to be
// 100% confident that an integrity check cannot be accidentally selected
// which results in reporting there is valid data when zero'd.
ZeroPersistentMemory();
auto& persistent = GetPersistentBuffer();
auto writer = persistent.GetWriter();
EXPECT_EQ(persistent.size(), 0u);
writer.Write(std::as_bytes(std::span(&kExpectedNumber, 1)));
ASSERT_TRUE(persistent.has_value());
persistent.~PersistentBuffer(); // Emulate shutdown / global destructors.
}
{ // Emulate a boot where persistent memory was kept as is.
auto& persistent = GetPersistentBuffer();
ASSERT_TRUE(persistent.has_value());
EXPECT_EQ(persistent.size(), sizeof(kExpectedNumber));
uint32_t temp = 0;
memcpy(&temp, persistent.data(), sizeof(temp));
EXPECT_EQ(temp, kExpectedNumber);
}
}
TEST_F(PersistentTest, LongData) {
constexpr std::string_view kTestString(
"A nice string should remain valid even if written incrementally!");
constexpr size_t kWriteSize = 5;
{ // Initialize the buffer.
RandomFillMemory();
auto& persistent = GetPersistentBuffer();
ASSERT_FALSE(persistent.has_value());
auto writer = persistent.GetWriter();
for (size_t i = 0; i < kTestString.length(); i += kWriteSize) {
writer.Write(kTestString.data() + i,
std::min(kWriteSize, kTestString.length() - i));
}
// Need to manually write a null terminator since std::string_view doesn't
// include one in the string length.
writer.Write(std::byte(0));
persistent.~PersistentBuffer(); // Emulate shutdown / global destructors.
}
{ // Ensure data is valid.
auto& persistent = GetPersistentBuffer();
ASSERT_TRUE(persistent.has_value());
ASSERT_STREQ(kTestString.data(),
reinterpret_cast<const char*>(persistent.data()));
}
}
TEST_F(PersistentTest, ZeroDataIsNoValue) {
ZeroPersistentMemory();
auto& persistent = GetPersistentBuffer();
EXPECT_FALSE(persistent.has_value());
}
TEST_F(PersistentTest, RandomDataIsInvalid) {
RandomFillMemory();
auto& persistent = GetPersistentBuffer();
ASSERT_FALSE(persistent.has_value());
}
TEST_F(PersistentTest, AppendingData) {
constexpr std::string_view kTestString("Test string one!");
constexpr uint32_t kTestNumber = 42;
{ // Initialize the buffer.
RandomFillMemory();
auto& persistent = GetPersistentBuffer();
auto writer = persistent.GetWriter();
EXPECT_EQ(persistent.size(), 0u);
// Write an integer.
writer.Write(std::as_bytes(std::span(&kTestNumber, 1)));
ASSERT_TRUE(persistent.has_value());
persistent.~PersistentBuffer(); // Emulate shutdown / global destructors.
}
{ // Get a pointer to the buffer and validate the contents.
auto& persistent = GetPersistentBuffer();
ASSERT_TRUE(persistent.has_value());
EXPECT_EQ(persistent.size(), sizeof(kTestNumber));
// Write more data.
auto writer = persistent.GetWriter();
EXPECT_EQ(persistent.size(), sizeof(kTestNumber));
writer.Write(std::as_bytes(std::span<const char>(kTestString)));
persistent.~PersistentBuffer(); // Emulate shutdown / global destructors.
}
{ // Ensure data was appended.
auto& persistent = GetPersistentBuffer();
ASSERT_TRUE(persistent.has_value());
EXPECT_EQ(persistent.size(), sizeof(kTestNumber) + kTestString.length());
}
}
} // namespace
} // namespace pw::persistent_ram
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