[WIP] support odpic 3.x

[flokli]

odpic 3.0.0 introduced some breaking changes.

From their changelog:

Version 3.0.0 (September 13, 2018)
----------------------------------

#)  Added support for Oracle Client 18 libraries.
#)  Added support for SODA (as preview). See
    :ref:`SODA Database<dpiSodaDbFunctions>`,
    :ref:`SODA Collection<dpiSodaCollFunctions>` and
    :ref:`SODA Document<dpiSodaDocFunctions>` for more information.
#)  Added support for call timeouts available in Oracle Client 18.1 and higher.
    See functions :func:`dpiConn_setCallTimeout()` and
    :func:`dpiConn_getCallTimeout()`.
#)  Added support for setting a LOB attribute of an object with string/bytes
    using the function :func:`dpiObject_setAttributeValue()`.
#)  Added support for the packed decimal type used by object attributes with
    historical types DECIMAL and NUMERIC
    (`cx_Oracle issue 212
    <https://github.com/oracle/python-cx_Oracle/issues/212>`__).
#)  On Windows, first attempt to load oci.dll from the same directory as the
    module that contains ODPI-C.
#)  SQL Objects that are created or fetched from the database are now tracked
    and marked unusable when a connection is closed. This was done in order to
    avoid a segfault in some circumstances.
#)  Improved support for closing pools by ensuring that once a pool has closed,
    further attempts to use connections acquired from that pool will fail with
    error "DPI-1010: not connected".
#)  Re-enabled pool pinging functionality for Oracle Client 12.2 and higher
    to handle classes of connection errors such as resource profile limits.
#)  Improved error messages when the Oracle Client or Oracle Database need to
    be at a minimum version in order to support a particular feature.
#)  Use plain integers instead of enumerations in order to simplify code and
    reduce the requirement for casts. Typedefs have been included so that code
    does not need to be changed.
#)  Eliminated potential buffer overrun
    (`issue 69 <https://github.com/oracle/odpi/issues/69>`__).
#)  In the Makefile for non-Windows platforms, the version information for
    ODPI-C is acquired directly from include/dpi.h as suggested
    (`issue 66 <https://github.com/oracle/odpi/issues/66>`__).
#)  Removed function dpiConn_newSubscription(). Use function
    :func:`dpiConn_subscribe()` instead.
#)  Removed function dpiLob_flushBuffer(). This function never worked anyway.
#)  Removed function dpiSubscr_close(). Use function
    :func:`dpiConn_unsubscribe()` instead.
#)  Removed function dpiVar_getData(). Use function
    :func:`dpiVar_getReturnedData()` instead.
#)  Added additional test cases.
#)  Improved documentation.

So far, I did the following:

• Followed the enum -> plain integer changes, which unfortunately is quite verbose, as c2hs doesn't support #define enums yet
• used the successors of some deprecated and removed methods. I'm not sure why we expose them like this in first place, and whether the way this is done now is the way it should be.
• remove the broken flushLob that upstream removed too. It never really worked anyhow.

I'm currently stuck at some weird CInt / CUInt problems, and lack the haskell-foo to do that on my own:

building
Preprocessing library for odpic-raw-0.3.0..
Building library for odpic-raw-0.3.0..
[1 of 6] Compiling Database.Dpi.Prelude ( src/Database/Dpi/Prelude.hs, dist/build/Database/Dpi/Prelude.o )
[2 of 6] Compiling Database.Dpi.Internal ( dist/build/Database/Dpi/Internal.hs, dist/build/Database/Dpi/Internal.o )

src/Database/Dpi/Internal.chs:1484:12: error:
    • Couldn't match expected type ‘CInt’ with actual type ‘CUInt’
    • In the ‘operations’ field of a record
      In the first argument of ‘return’, namely
        ‘Data_SubscrCreateParams {..}’
      In a stmt of a 'do' block: return Data_SubscrCreateParams {..}
     |
1484 | #if DPI_MAJOR_VERSION >= 2 && DPI_MINOR_VERSION >= 4
     |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: keeping build directory '/tmp/nix-build-odpic-raw-0.3.0.drv-16'
builder for '/nix/store/v0w2w6vbvfw83l84mj81gy9zszcaxkpw-odpic-raw-0.3.0.drv' failed with exit code 1
error: build of '/nix/store/v0w2w6vbvfw83l84mj81gy9zszcaxkpw-odpic-raw-0.3.0.drv' failed

I'd appreciate if somebody could take it over from here.

fixes #13

[flokli]

Uff, this wasn't complete, and still fails to build, see my last comment.

[leptonyu]

@flokli fine, let me check later.

[flokli]

@leptonyu thanks. Seems the enum mapping could also be made a bit less verbose by using

{#enum define…}

see https://github.com/haskell/c2hs/blob/7e45dc8497bf38054f00e9e2c46f5a525a299273/tests/bugs/issue-102/Issue102.chs#L22