pw_kvs: KeyDescriptor cleanup
- The key and value reading functions only need an address, not the
KeyDescriptor.
- Have the KeyDescriptor initialize its own hash.
- Remove redundant FlashPartition::Address alias.
Change-Id: I80309f95f6cb0a39dbf12dfa874966d7ff1024fd
diff --git a/pw_kvs/key_value_store.cc b/pw_kvs/key_value_store.cc
index 94d4b32..f9f7811 100644
--- a/pw_kvs/key_value_store.cc
+++ b/pw_kvs/key_value_store.cc
@@ -28,25 +28,6 @@
using std::byte;
using std::string_view;
-namespace {
-
-using Address = FlashPartition::Address;
-
-// constexpr uint32_t SixFiveFiveNineNine(std::string_view string) {
-constexpr uint32_t HashKey(std::string_view string) {
- uint32_t hash = 0;
- uint32_t coefficient = 65599u;
-
- for (char ch : string) {
- hash += coefficient * unsigned(ch);
- coefficient *= 65599u;
- }
-
- return hash;
-}
-
-} // namespace
-
Status KeyValueStore::Init() {
// Reset the number of occupied key descriptors; we will fill them later.
key_descriptor_list_size_ = 0;
@@ -124,10 +105,8 @@
for (size_t key_id = 0; key_id < key_descriptor_list_size_; ++key_id) {
uint32_t sector_id =
key_descriptor_list_[key_id].address / sector_size_bytes;
- KeyDescriptor key_descriptor;
- key_descriptor.address = key_descriptor_list_[key_id].address;
EntryHeader header;
- TRY(ReadEntryHeader(key_descriptor, &header));
+ TRY(ReadEntryHeader(key_descriptor_list_[key_id].address, &header));
sector_map_[sector_id].valid_bytes += header.size();
}
initialized_ = true;
@@ -138,11 +117,8 @@
Address* next_entry_address) {
const size_t alignment_bytes = partition_.alignment_bytes();
- KeyDescriptor key_descriptor;
- key_descriptor.address = entry_address;
-
EntryHeader header;
- TRY(ReadEntryHeader(key_descriptor, &header));
+ TRY(ReadEntryHeader(entry_address, &header));
// TODO: Should likely add a "LogHeader" method or similar.
DBG("Header: ");
DBG(" Address = 0x%zx", size_t(entry_address));
@@ -157,7 +133,6 @@
if (HeaderLooksLikeUnwrittenData(header)) {
return Status::NOT_FOUND;
}
- key_descriptor.key_version = header.key_version();
// TODO: Handle multiple magics for formats that have changed.
if (header.magic() != entry_header_format_.magic) {
@@ -171,12 +146,13 @@
// Read the key from flash & validate the entry (which reads the value).
KeyBuffer key_buffer;
- TRY(ReadEntryKey(key_descriptor, header.key_length(), key_buffer.data()));
+ TRY(ReadEntryKey(entry_address, header.key_length(), key_buffer.data()));
const string_view key(key_buffer.data(), header.key_length());
TRY(header.VerifyChecksumInFlash(
- &partition_, key_descriptor.address, entry_header_format_.checksum));
- key_descriptor.key_hash = HashKey(key);
+ &partition_, entry_address, entry_header_format_.checksum));
+
+ KeyDescriptor key_descriptor(key, header.key_version(), entry_address);
DBG("Key hash: %zx (%zu)",
size_t(key_descriptor.key_hash),
@@ -257,7 +233,7 @@
TRY(FindKeyDescriptor(key, &key_descriptor));
EntryHeader header;
- TRY(ReadEntryHeader(*key_descriptor, &header));
+ TRY(ReadEntryHeader(key_descriptor->address, &header));
StatusWithSize result = ReadEntryValue(*key_descriptor, header, value_buffer);
if (result.ok() && options_.verify_on_read) {
@@ -301,9 +277,9 @@
std::memset(entry_.key_buffer_.data(), 0, entry_.key_buffer_.size());
EntryHeader header;
- if (entry_.kvs_.ReadEntryHeader(descriptor, &header).ok()) {
+ if (entry_.kvs_.ReadEntryHeader(descriptor.address, &header).ok()) {
entry_.kvs_.ReadEntryKey(
- descriptor, header.key_length(), entry_.key_buffer_.data());
+ descriptor.address, header.key_length(), entry_.key_buffer_.data());
}
return entry_;
@@ -316,11 +292,23 @@
TRY(FindKeyDescriptor(key, &key_descriptor));
EntryHeader header;
- TRY(ReadEntryHeader(*key_descriptor, &header));
+ TRY(ReadEntryHeader(key_descriptor->address, &header));
return StatusWithSize(header.value_length());
}
+uint32_t KeyValueStore::HashKey(string_view string) {
+ uint32_t hash = 0;
+ uint32_t coefficient = 65599u;
+
+ for (char ch : string) {
+ hash += coefficient * unsigned(ch);
+ coefficient *= 65599u;
+ }
+
+ return hash;
+}
+
Status KeyValueStore::FixedSizeGet(std::string_view key,
byte* value,
size_t size_bytes) const {
@@ -354,7 +342,7 @@
for (auto& descriptor : key_descriptors()) {
if (descriptor.key_hash == hash) {
DBG("Found match! For hash: %zx", size_t(hash));
- TRY(ReadEntryKey(descriptor, key.size(), key_buffer));
+ TRY(ReadEntryKey(descriptor.address, key.size(), key_buffer));
if (key == string_view(key_buffer, key.size())) {
DBG("Keys matched too");
@@ -366,12 +354,12 @@
return Status::NOT_FOUND;
}
-Status KeyValueStore::ReadEntryHeader(const KeyDescriptor& descriptor,
+Status KeyValueStore::ReadEntryHeader(Address address,
EntryHeader* header) const {
- return partition_.Read(descriptor.address, sizeof(*header), header).status();
+ return partition_.Read(address, sizeof(*header), header).status();
}
-Status KeyValueStore::ReadEntryKey(const KeyDescriptor& descriptor,
+Status KeyValueStore::ReadEntryKey(Address address,
size_t key_length,
char* key) const {
// TODO: This check probably shouldn't be here; this is like
@@ -384,8 +372,7 @@
return Status::DATA_LOSS;
}
// The key is immediately after the entry header.
- return partition_
- .Read(descriptor.address + sizeof(EntryHeader), key_length, key)
+ return partition_.Read(address + sizeof(EntryHeader), key_length, key)
.status();
}
@@ -450,8 +437,9 @@
// store the key and value in the TempEntry stored in the static allocated
// working_buffer_.
EntryHeader header;
- TRY(ReadEntryHeader(key_descriptor, &header));
- TRY(ReadEntryKey(key_descriptor, header.key_length(), entry->key.data()));
+ TRY(ReadEntryHeader(key_descriptor.address, &header));
+ TRY(ReadEntryKey(
+ key_descriptor.address, header.key_length(), entry->key.data()));
string_view key = string_view(entry->key.data(), header.key_length());
StatusWithSize result = ReadEntryValue(
key_descriptor, header, as_writable_bytes(span(entry->value)));
diff --git a/pw_kvs/public/pw_kvs/key_value_store.h b/pw_kvs/public/pw_kvs/key_value_store.h
index f38592d..8661251 100644
--- a/pw_kvs/public/pw_kvs/key_value_store.h
+++ b/pw_kvs/public/pw_kvs/key_value_store.h
@@ -207,6 +207,11 @@
using Address = FlashPartition::Address;
struct KeyDescriptor {
+ KeyDescriptor() = default;
+
+ KeyDescriptor(std::string_view key, uint32_t version, Address address)
+ : key_hash(HashKey(key)), key_version(version), address(address) {}
+
uint32_t key_hash;
uint32_t key_version;
Address address; // In partition address.
@@ -221,6 +226,8 @@
}
};
+ static uint32_t HashKey(std::string_view string);
+
Status FixedSizeGet(std::string_view key,
std::byte* value,
size_t size_bytes) const;
@@ -240,11 +247,8 @@
key, const_cast<const KeyDescriptor**>(result));
}
- Status ReadEntryHeader(const KeyDescriptor& descriptor,
- EntryHeader* header) const;
- Status ReadEntryKey(const KeyDescriptor& descriptor,
- size_t key_length,
- char* key) const;
+ Status ReadEntryHeader(Address address, EntryHeader* header) const;
+ Status ReadEntryKey(Address address, size_t key_length, char* key) const;
StatusWithSize ReadEntryValue(const KeyDescriptor& key_descriptor,
const EntryHeader& header,
