pgsql: Refactor CopyOneRowTo

Refactor CopyOneRowTo

The handling of binary and text formats are quite different here, so
it's more clear to check for the format first and have two separate
loops.

Author: jian he <jian.universality@gmail.com>
Reviewed-by: Ilia Evdokimov, Junwang Zhao
Discussion: https://www.postgresql.org/message-id/CACJufxFzHCeFBQF0M%2BSgk_NwknWuQ4oU7tS1isVeBrbhcKOHkg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3943da46bc54006ec4849bc7541cf4e674b700eb

Modified Files
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src/backend/commands/copyto.c | 39 ++++++++++++++++++++-------------------
1 file changed, 20 insertions(+), 19 deletions(-)