table/bloom_block.*: pass func parameter by reference

[table/bloom_block.h:29]: (performance) Function parameter
 'keys_hashes' should be passed by reference.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
db/version_set.cc: use !empty() instead of 'size() > 0'

Use empty() since it should be prefered as it has, following
the standard, a constant time complexity regardless of the
containter type. The same is not guaranteed for size().

Fix for:
[db/version_set.cc:2250]: (performance) Possible inefficient
 checking for 'column_families_not_found' emptiness.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
table/cuckoo_table_reader.cc: pass func parameter by ref

Fix for:

[table/cuckoo_table_reader.cc:198]: (performance) Function
 parameter 'file_data' should be passed by reference.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
table/table_test.cc: pass func parameter by reference

Fix for:

[table/table_test.cc:1218]: (performance) Function parameter
 'prefix' should be passed by reference.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ldb_cmd_execute_result.h: perform init in initialization list

Fix for:

[util/ldb_cmd_execute_result.h:18]: (performance) Variable 'message_'
 is assigned in constructor body. Consider performing initialization
 in initialization list.
[util/ldb_cmd_execute_result.h:23]: (performance) Variable 'message_'
 is assigned in constructor body. Consider performing initialization
 in initialization list.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
db_ttl_impl.h: pass func parameter by reference

Fix for:

[utilities/ttl/db_ttl_impl.h:209]: (performance) Function parameter
 'merge_op' should be passed by reference.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
db/db_impl.cc: fix object handling, remove double lines

Fix for:

[db/db_impl.cc:4039]: (error) Instance of 'StopWatch' object is
 destroyed immediately.
[db/db_impl.cc:4042]: (error) Instance of 'StopWatch' object is
 destroyed immediately.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
util/signal_test.cc: suppress intentional null pointer deref

Add comment to enabele cppcheck suppression of intentional null
pointer deref via --inline-suppr option.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
util/ldb_cmd.cc: prefer prefix ++operator for non-primitive types

Prefer prefix ++operator for non-primitive types like iterators for
performance reasons. Prefix ++/-- operators avoid creating a temporary
copy.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
document_db.cc: pass const parameter by reference

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
spatialdb/spatial_db.cc: use !empty() instead of 'size() > 0'

Use empty() since it should be prefered as it has, following
the standard, a constant time complexity regardless of the
containter type. The same is not guaranteed for size().

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ttl/ttl_test.cc: prefer prefix ++operator for non-primitive types

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
in_table_factory.cc: use correct format specifier

Use %zu instead of %zd since size_t and uint32_t are unsigned.

Fix for:

[table/plain_table_factory.cc:55]: (warning) %zd in format string (no. 1)
 requires 'ssize_t' but the argument type is 'size_t {aka unsigned long}'.
[table/plain_table_factory.cc:58]: (warning) %zd in format string (no. 1)
 requires 'ssize_t' but the argument type is 'size_t {aka unsigned long}'.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
document_db.cc: fix assert

Check for lhs and not twice for rhs.

Fix for:

[utilities/document/document_db.cc:36] ->
 [utilities/document/document_db.cc:36]: (style) Same expression on both
 sides of '&&'.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
compaction_picker.cc: remove check for >=0 for unsigned

Fix for:

[db/compaction_picker.cc:923]: (style) Unsigned variable
 'start_index' can't be negative so it is unnecessary to test it.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
db/db_impl.cc: reduce scope of prefix_initialized

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
db/memtable.cc: remove unused variable merge_result

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>