Summary:
This patch addes ColumnFamilyHandle::GetDescriptor(), which allows
developers to obtain the CF options and names of the associated column
family given its handle.
// Returns the up-to-date descriptor used by the current handle. Since it
// returns the up-to-date information, this call might internally locks
// and releases DB mutex to access the up-to-date CF options.
virtual ColumnFamilyDescriptor GetDescriptor() = 0;
Test Plan: augment column_family_test
Reviewers: sdong, yoshinorim, IslamAbdelRahman, rven, kradhakrishnan, anthony
Reviewed By: anthony
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D51543