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authorRoman Smrž <roman.smrz@seznam.cz>2019-10-26 22:19:56 +0200
committerRoman Smrž <roman.smrz@seznam.cz>2019-12-10 21:29:28 +0100
commit361891f25ca735fd85db64a14823cc55b8a0619a (patch)
treed45734fbc123d8dcb26128b314eb4453ecdd154e /include/erebos
parent1a1b36dea942cd7b18067f3f1220c9ab4f9b4448 (diff)
Basic object encoding and storage
Diffstat (limited to 'include/erebos')
-rw-r--r--include/erebos/storage.h172
1 files changed, 172 insertions, 0 deletions
diff --git a/include/erebos/storage.h b/include/erebos/storage.h
new file mode 100644
index 0000000..ae899f5
--- /dev/null
+++ b/include/erebos/storage.h
@@ -0,0 +1,172 @@
+#pragma once
+
+#include <array>
+#include <filesystem>
+#include <memory>
+#include <optional>
+#include <string>
+#include <variant>
+#include <vector>
+
+namespace erebos {
+
+class Storage;
+class Digest;
+class Ref;
+class Object;
+
+class Storage
+{
+public:
+ Storage(const Storage &) = default;
+ Storage & operator=(const Storage &) = delete;
+
+ static std::optional<Storage> open(std::filesystem::path path);
+ std::optional<Ref> ref(const Digest &) const;
+ std::optional<Object> load(const Digest &) const;
+ Ref store(const Object &) const;
+
+private:
+ friend class Ref;
+ struct Priv;
+ const std::shared_ptr<const Priv> p;
+ Storage(const std::shared_ptr<const Priv> p): p(p) {}
+};
+
+class Digest
+{
+public:
+ static constexpr size_t size = 32;
+
+ Digest(const Digest &) = default;
+ Digest & operator=(const Digest &) = delete;
+
+ explicit Digest(std::array<uint8_t, size> value): value(value) {}
+ explicit Digest(const std::string &);
+ explicit operator std::string() const;
+
+ bool operator==(const Digest & other) const { return value == other.value; }
+ bool operator!=(const Digest & other) const { return value != other.value; }
+ bool operator<(const Digest & other) const { return value < other.value; }
+ bool operator<=(const Digest & other) const { return value <= other.value; }
+ bool operator>(const Digest & other) const { return value > other.value; }
+ bool operator>=(const Digest & other) const { return value >= other.value; }
+
+private:
+ std::array<uint8_t, size> value;
+};
+
+class Ref
+{
+public:
+ Ref(const Ref &) = default;
+ Ref & operator=(const Ref &) = delete;
+
+ static std::optional<Ref> create(Storage, const Digest &);
+
+ const Digest & digest() const;
+ const Object & operator*() const;
+ const Object * operator->() const;
+
+private:
+ friend class Storage;
+ struct Priv;
+ const std::shared_ptr<const Priv> p;
+ Ref(const std::shared_ptr<const Priv> p): p(p) {}
+};
+
+class Record
+{
+public:
+ class Item {
+ public:
+ typedef std::variant<
+ int,
+ std::string,
+ std::vector<uint8_t>,
+ Ref> Variant;
+
+ Item(const std::string & name, Variant value):
+ name(name), value(value) {}
+ Item(const Item &) = default;
+ Item & operator=(const Item &) = delete;
+
+ std::optional<int> asInteger() const;
+ std::optional<std::string> asText() const;
+ std::optional<std::vector<uint8_t>> asBinary() const;
+ std::optional<Ref> asRef() const;
+
+ private:
+ friend class Record;
+ std::string name;
+ Variant value;
+ };
+
+private:
+ Record(const std::shared_ptr<std::vector<Item>> & ptr):
+ ptr(ptr) {}
+
+public:
+ Record(const std::vector<Item> &);
+ std::vector<uint8_t> encode() const;
+
+ const std::vector<Item> & items() const;
+ std::optional<Item> item(const std::string & name) const;
+ std::optional<Item> operator[](const std::string & name) const;
+ std::vector<Item> items(const std::string & name) const;
+
+private:
+ friend class Object;
+ std::vector<uint8_t> encodeInner() const;
+ static Record decode(Storage,
+ std::vector<uint8_t>::const_iterator,
+ std::vector<uint8_t>::const_iterator);
+
+ const std::shared_ptr<const std::vector<Item>> ptr;
+};
+
+class Blob
+{
+public:
+ Blob(const std::vector<uint8_t> &);
+
+ const std::vector<uint8_t> & data() const { return *ptr; }
+ std::vector<uint8_t> encode() const;
+
+private:
+ friend class Object;
+ std::vector<uint8_t> encodeInner() const;
+ static Blob decode(Storage,
+ std::vector<uint8_t>::const_iterator,
+ std::vector<uint8_t>::const_iterator);
+
+ Blob(std::shared_ptr<std::vector<uint8_t>> ptr): ptr(ptr) {}
+
+ const std::shared_ptr<const std::vector<uint8_t>> ptr;
+};
+
+class Object
+{
+public:
+ typedef std::variant<
+ Record,
+ Blob> Variants;
+
+ Object(const Object &) = default;
+ Object(Variants content): content(content) {}
+ Object & operator=(const Object &) = delete;
+
+ static std::optional<Object> decode(Storage, const std::vector<uint8_t> &);
+ std::vector<uint8_t> encode() const;
+
+ std::optional<Record> asRecord() const;
+ std::optional<Blob> asBlob() const;
+
+private:
+ friend class Record;
+ friend class Blob;
+
+ Variants content;
+};
+
+}