Progress #4: Groundwork for part 2

Preparing for only writing irreversible blocks to disk; first I needed to
update the various block fetching methods on database to account for
this. This commit contains those updates, as well as a shiny new unit
test to make sure those methods are still working correctly.

libraries/chain/database.cpp

@@ -61,26 +61,35 @@ bool database::is_known_transaction( const transaction_id_type& id )const
    return trx_idx.find( id ) != trx_idx.end();
 }
 
-block_id_type  database::get_block_id_for_num( uint32_t block_num )const
+block_id_type database::get_block_id_for_num(uint32_t block_num)const
 { try {
-   return _block_id_to_block.fetch_block_id( block_num );
-} FC_CAPTURE_AND_RETHROW( (block_num) ) }
+   if (const auto& block = fetch_block_by_number(block_num))
+      return block->id();
 
-optional<signed_block> database::fetch_block_by_id( const block_id_type& id )const
+   FC_THROW_EXCEPTION(unknown_block_exception, "Could not find block");
+} FC_CAPTURE_AND_RETHROW((block_num)) }
+
+optional<signed_block> database::fetch_block_by_id(const block_id_type& id)const
 {
-   auto b = _fork_db.fetch_block( id );
-   if( !b )
-      return _block_id_to_block.fetch_optional(id);
-   return b->data;
+   auto b = _fork_db.fetch_block(id);
+   if(b) return b->data;
+   return _block_id_to_block.fetch_optional(id);
 }
 
 optional<signed_block> database::fetch_block_by_number( uint32_t num )const
 {
-   auto results = _fork_db.fetch_block_by_number(num);
-   if( results.size() == 1 )
-      return results[0]->data;
-   else
-      return _block_id_to_block.fetch_by_number(num);
+   if (const auto& block = _block_id_to_block.fetch_by_number(num))
+      return *block;
+
+   // Not in _block_id_to_block, so it must be since the last irreversible block. Grab it from _fork_db instead
+   if (num <= head_block_num()) {
+      auto block = _fork_db.head();
+      while (block && block->num > num)
+         block = block->prev.lock();
+      if (block && block->num == num)
+         return block->data;
+   }
+
    return optional<signed_block>();
 }
 

libraries/chain/include/eos/chain/exceptions.hpp

@@ -77,6 +77,7 @@ namespace eos { namespace chain {
    FC_DECLARE_DERIVED_EXCEPTION( undo_database_exception,           eos::chain::chain_exception, 3070000, "undo database exception" )
    FC_DECLARE_DERIVED_EXCEPTION( unlinkable_block_exception,        eos::chain::chain_exception, 3080000, "unlinkable block" )
    FC_DECLARE_DERIVED_EXCEPTION( black_swan_exception,              eos::chain::chain_exception, 3090000, "black swan" )
+   FC_DECLARE_DERIVED_EXCEPTION( unknown_block_exception,           eos::chain::chain_exception, 3100000, "unknown block" )
 
    FC_DECLARE_DERIVED_EXCEPTION( tx_missing_active_auth,            eos::chain::transaction_exception, 3030001, "missing required active authority" )
    FC_DECLARE_DERIVED_EXCEPTION( tx_missing_owner_auth,             eos::chain::transaction_exception, 3030002, "missing required owner authority" )
@@ -119,7 +120,6 @@ namespace eos { namespace chain {
    FC_DECLARE_DERIVED_EXCEPTION( invalid_committee_member_signee,           eos::chain::chain_exception, 30021, "invalid committee_member signee" )
    FC_DECLARE_DERIVED_EXCEPTION( failed_checkpoint_verification,    eos::chain::chain_exception, 30022, "failed checkpoint verification" )
    FC_DECLARE_DERIVED_EXCEPTION( wrong_chain_id,                    eos::chain::chain_exception, 30023, "wrong chain id" )
-   FC_DECLARE_DERIVED_EXCEPTION( unknown_block,                     eos::chain::chain_exception, 30024, "unknown block" )
    FC_DECLARE_DERIVED_EXCEPTION( block_older_than_undo_history,     eos::chain::chain_exception, 30025, "block is older than our undo history allows us to process" )
 
    FC_DECLARE_EXCEPTION( evaluation_error, 31000, "Evaluation Error" )

tests/tests/database_tests.cpp

@@ -22,14 +22,13 @@
  * THE SOFTWARE.
  */
 
-#include <boost/test/unit_test.hpp>
-
 #include <eos/chain/database.hpp>
-
 #include <eos/chain/account_object.hpp>
 
 #include <fc/crypto/digest.hpp>
 
+#include <boost/test/unit_test.hpp>
+
 #include "../common/database_fixture.hpp"
 
 using namespace eos::chain;
@@ -58,3 +57,48 @@ BOOST_FIXTURE_TEST_CASE(undo_test, testing_fixture)
       throw;
    }
 }
+
+BOOST_FIXTURE_TEST_CASE(get_blocks, testing_fixture)
+{ try {
+      MKDB(db)
+
+      // I apologize if this proves fragile in the future. Any changes to how block IDs are calculated, or producer
+      // scheduling, etc. will break this, but hopefully it should be pretty easy to just swap in the new IDs... :]
+      block_id_type block_ids[] = {
+         block_id_type("0000000130e605ebe8ba3da0d5d1ed556ccfde3b"),
+         block_id_type("00000002a23c51a99d8d32b671012ebc221a4098"),
+         block_id_type("00000003eaf03b2aca76f64db5e640325c0e7b3f"),
+         block_id_type("000000041e533056ead792fd5935d23c84311b30"),
+         block_id_type("000000058aa9a6436929741ffee02fed1f2b4290"),
+         block_id_type("000000063037551d2353ffb0ab07a9b5e582e66b"),
+         block_id_type("00000007f3960fb247bd95feb9280565b4a0eb2e"),
+         block_id_type("0000000893bd630f901ff78bd5d5a28574698f45"),
+         block_id_type("0000000928143087ee97d5429be8282b1ce2d323"),
+         block_id_type("0000000a3b9c0c3a596069f36f678f0e69a6a7a4"),
+         block_id_type("0000000bf05985672af3481f1f1c780ac40b1299"),
+         block_id_type("0000000c6665f984a6e994c7732255aaab25dee2"),
+         block_id_type("0000000d3cf47c047f681451508efd07d418574c"),
+         block_id_type("0000000e62d6764b69c4d2bb72047676bfff5e79"),
+         block_id_type("0000000f85aa69d6f5d900e3e26daf5f19d91d91"),
+         block_id_type("000000106c1e81538bf6ce21e9d000d7c9beb20e"),
+         block_id_type("00000011cd6a0d410addfdf8c7816c168e24af6e"),
+         block_id_type("000000120b333f3264d605127b50e28b9679279f"),
+         block_id_type("000000138983847a10b1dc66503c556e9e66f461"),
+         block_id_type("0000001420541bed52c10949a82c5d0b311fb489")
+      };
+
+      db.produce_blocks(20);
+      for (int i = 0; i < 20; ++i) {
+         BOOST_CHECK(db.is_known_block(block_ids[i]));
+         BOOST_CHECK_EQUAL(db.get_block_id_for_num(i+1), block_ids[i]);
+         BOOST_CHECK_EQUAL(db.fetch_block_by_id(block_ids[i])->block_num(), i+1);
+         BOOST_CHECK_EQUAL(db.fetch_block_by_number(i+1)->id(), block_ids[i]);
+      }
+
+      BOOST_CHECK_EQUAL(db.last_irreversible_block_num(), 13);
+      BOOST_CHECK_THROW(db.get_block_id_for_num(21), eos::chain::unknown_block_exception);
+
+      db.produce_blocks();
+      BOOST_CHECK_EQUAL(db.last_irreversible_block_num(), 14);
+      BOOST_CHECK_EQUAL(db.get_block_id_for_num(21), db.head_block_id());
+} FC_LOG_AND_RETHROW() }