Add class description to mostly of bootstrap classes (#3725)

nano/node/bootstrap/bootstrap.hpp

@@ -63,6 +63,10 @@ class pulls_cache final
 	// clang-format on
 	constexpr static std::size_t cache_size_max = 10000;
 };
+
+/**
+ * Container for bootstrap sessions that are active. Owned by bootstrap_initiator.
+ */
 class bootstrap_attempts final
 {
 public:
@@ -76,6 +80,10 @@ class bootstrap_attempts final
 	std::map<uint64_t, std::shared_ptr<nano::bootstrap_attempt>> attempts;
 };
 
+/**
+ * Client side portion to initiate bootstrap sessions. Prevents multiple legacy-type bootstrap sessions from being started at the same time. Does permit
+ * lazy/wallet bootstrap sessions to overlap with legacy sessions.
+ */
 class bootstrap_initiator final
 {
 public:
@@ -117,6 +125,10 @@ class bootstrap_initiator final
 };
 
 std::unique_ptr<container_info_component> collect_container_info (bootstrap_initiator & bootstrap_initiator, std::string const & name);
+
+/**
+ * Defines the numeric values for the bootstrap feature.
+ */
 class bootstrap_limits final
 {
 public:

nano/node/bootstrap/bootstrap_attempt.hpp

@@ -11,6 +11,10 @@ class node;
 
 class frontier_req_client;
 class bulk_push_client;
+
+/**
+ * Polymorphic base class for bootstrap sessions.
+ */
 class bootstrap_attempt : public std::enable_shared_from_this<bootstrap_attempt>
 {
 public:

nano/node/bootstrap/bootstrap_bulk_pull.hpp

@@ -25,6 +25,10 @@ class pull_info
 	uint64_t bootstrap_id{ 0 };
 };
 class bootstrap_client;
+
+/**
+ * Client side of a bulk_pull request. Created when the bootstrap_attempt wants to make a bulk_pull request to the remote side.
+ */
 class bulk_pull_client final : public std::enable_shared_from_this<nano::bulk_pull_client>
 {
 public:
@@ -59,6 +63,12 @@ class bulk_pull_account_client final : public std::enable_shared_from_this<nano:
 };
 class bootstrap_server;
 class bulk_pull;
+
+/**
+ * Server side of a bulk_pull request. Created when bootstrap_server receives a bulk_pull message and is exited after the contents
+ * have been sent. If the 'start' in the bulk_pull message is an account, send blocks for that account down to 'end'. If the 'start'
+ * is a block hash, send blocks for that chain down to 'end'. If end doesn't exist, send all accounts in the chain.
+ */
 class bulk_pull_server final : public std::enable_shared_from_this<nano::bulk_pull_server>
 {
 public:

nano/node/bootstrap/bootstrap_bulk_push.hpp

@@ -8,6 +8,10 @@ namespace nano
 {
 class bootstrap_attempt;
 class bootstrap_client;
+
+/**
+ * Client side of a bulk_push request. Sends a sequence of blocks the other side did not report in their frontier_req response.
+ */
 class bulk_push_client final : public std::enable_shared_from_this<nano::bulk_push_client>
 {
 public:
@@ -23,6 +27,10 @@ class bulk_push_client final : public std::enable_shared_from_this<nano::bulk_pu
 	std::pair<nano::block_hash, nano::block_hash> current_target;
 };
 class bootstrap_server;
+
+/**
+ * Server side of a bulk_push request. Receives blocks and puts them in the block processor to be processed.
+ */
 class bulk_push_server final : public std::enable_shared_from_this<nano::bulk_push_server>
 {
 public:

nano/node/bootstrap/bootstrap_connections.hpp

@@ -18,6 +18,10 @@ class bootstrap_attempt;
 class bootstrap_connections;
 class frontier_req_client;
 class pull_info;
+
+/**
+ * Owns the client side of the bootstrap connection.
+ */
 class bootstrap_client final : public std::enable_shared_from_this<bootstrap_client>
 {
 public:
@@ -42,6 +46,10 @@ class bootstrap_client final : public std::enable_shared_from_this<bootstrap_cli
 	std::chrono::steady_clock::time_point start_time_m;
 };
 
+/**
+ * Container for bootstrap_client objects. Owned by bootstrap_initiator which pools open connections and makes them available
+ * for use by different bootstrap sessions.
+ */
 class bootstrap_connections final : public std::enable_shared_from_this<bootstrap_connections>
 {
 public:

nano/node/bootstrap/bootstrap_frontier.hpp

@@ -9,6 +9,10 @@ namespace nano
 {
 class bootstrap_attempt;
 class bootstrap_client;
+
+/**
+ * Client side of a frontier request. Created to send and listen for frontier sequences from the server.
+ */
 class frontier_req_client final : public std::enable_shared_from_this<nano::frontier_req_client>
 {
 public:
@@ -36,6 +40,10 @@ class frontier_req_client final : public std::enable_shared_from_this<nano::fron
 };
 class bootstrap_server;
 class frontier_req;
+
+/**
+ * Server side of a frontier request. Created when a bootstrap_server receives a frontier_req message and exited when end-of-list is reached.
+ */
 class frontier_req_server final : public std::enable_shared_from_this<nano::frontier_req_server>
 {
 public:

nano/node/bootstrap/bootstrap_lazy.hpp

@@ -23,6 +23,11 @@ class lazy_state_backlog_item final
 	nano::uint128_t balance{ 0 };
 	unsigned retry_limit{ 0 };
 };
+
+/**
+ * Lazy bootstrap session. Started with a block hash, this will "trace down" the blocks obtained to find a connection to the ledger.
+ * This attempts to quickly bootstrap a section of the ledger given a hash that's known to be confirmed.
+ */
 class bootstrap_attempt_lazy final : public bootstrap_attempt
 {
 public:
@@ -60,6 +65,10 @@ class bootstrap_attempt_lazy final : public bootstrap_attempt
 	/** The maximum number of records to be read in while iterating over long lazy containers */
 	static uint64_t constexpr batch_read_size = 256;
 };
+
+/**
+ * Wallet bootstrap session. This session will trace down accounts within local wallets to try and bootstrap those blocks first.
+ */
 class bootstrap_attempt_wallet final : public bootstrap_attempt
 {
 public:

nano/node/bootstrap/bootstrap_legacy.hpp

@@ -13,6 +13,9 @@ namespace nano
 {
 class node;
 
+/**
+ * Legacy bootstrap session. This is made up of 3 phases: frontier requests, bootstrap pulls, bootstrap pushes.
+ */
 class bootstrap_attempt_legacy : public bootstrap_attempt
 {
 public:

nano/node/bootstrap/bootstrap_server.hpp

@@ -9,6 +9,10 @@
 namespace nano
 {
 class bootstrap_server;
+
+/**
+ * Server side portion of bootstrap sessions. Listens for new socket connections and spawns bootstrap_server objects when connected.
+ */
 class bootstrap_listener final
 {
 public:
@@ -32,6 +36,10 @@ class bootstrap_listener final
 std::unique_ptr<container_info_component> collect_container_info (bootstrap_listener & bootstrap_listener, std::string const & name);
 
 class message;
+
+/**
+ * Owns the server side of a bootstrap connection. Responds to bootstrap messages sent over the socket.
+ */
 class bootstrap_server final : public std::enable_shared_from_this<nano::bootstrap_server>
 {
 public: