Add GDALSetAdbcDriverInitFunc() and use it in OGR ADBC driver

doc/source/api/vector_c_api.rst

@@ -14,3 +14,6 @@ ogr_core.h and ogr_api.h: Vector C API
 
 .. doxygenfile:: ogr_api.h
    :project: api
+
+.. doxygenfile:: gdal_adbc.h
+   :project: api

doc/source/drivers/vector/adbc.rst

@@ -80,6 +80,16 @@ It returns for each table a OGR feature with the following fields (some
 potentially unset or with an empty string): ``catalog_name``, ``schema_name``,
 ``table_name``, ``table_type``.
 
+Custom driver entry point
+-------------------------
+
+A custom driver entry point can be specified by applications by calling
+:cpp:func:`GDALSetAdbcDriverInitFunc` (defined in header :file:`gdal_adbc.h`)
+before using the driver. The specified init function will be used by the
+GDAL ADBC driver as a way of specifying the ADBC driver for all calls in the
+same thread. Setting both the init function and the ``ADBC_DRIVER`` open
+option is not supported.
+
 Examples
 --------
 

gcore/CMakeLists.txt

@@ -1,6 +1,7 @@
 # CMake4GDAL project is distributed under MIT license. See accompanying file LICENSE.txt.
 add_library(
   gcore OBJECT
+  gdal_adbc.cpp
   gdalopeninfo.cpp
   gdaldriver.cpp
   gdaldrivermanager.cpp
@@ -194,6 +195,7 @@ target_public_header(
   gdalgeorefpamdataset.h
   gdal_mdreader.h
   gdalsubdatasetinfo.h
+  gdal_adbc.h
 )
 
 set(GDAL_DATA_FILES

gcore/gdal_adbc.cpp

@@ -0,0 +1,62 @@
+/******************************************************************************
+ * Name:     gdal_adbc.h
+ * Project:  GDAL Core
+ * Purpose:  GDAL Core ADBC related declarations.
+ * Author:   Even Rouault <even dot rouault at spatialys.com>
+ *
+ ******************************************************************************
+ * Copyright (c) 2024, Even Rouault <even dot rouault at spatialys.com>
+ *
+ * SPDX-License-Identifier: MIT
+ ****************************************************************************/
+
+#include "cpl_port.h"
+
+// Very minimal extract of adbc.h
+#define ADBC
+
+CPL_C_START
+
+typedef uint8_t AdbcStatusCode;
+struct AdbcError;
+typedef AdbcStatusCode (*AdbcDriverInitFunc)(int version, void *driver,
+                                             struct AdbcError *error);
+
+CPL_C_END
+
+#include "gdal_adbc.h"
+
+//! Thread local ADBC driver initialization function
+static thread_local AdbcDriverInitFunc tlAdbcDriverInitFunc = nullptr;
+
+/************************************************************************/
+/*                       GDALSetAdbcDriverInitFunc()                    */
+/************************************************************************/
+
+/** Sets the ADBC driver initialization function that should be used during
+ * the next calls to the OGR ADBC driver.
+ *
+ * This is a thread-local setting.
+ *
+ * When set, it is honored by the OGR ADBC driver to pass the specified
+ * initialization function as the argument of
+ * AdbcDriverManagerDatabaseSetInitFunc()
+ *
+ * Setting it to NULL resets to the the default behaviour of the ADBC driver,
+ * which is to honor the ADBC_DRIVER open option.
+ */
+void GDALSetAdbcDriverInitFunc(AdbcDriverInitFunc init_func)
+{
+    tlAdbcDriverInitFunc = init_func;
+}
+
+/************************************************************************/
+/*                       GDALGetAdbcDriverInitFunc()                    */
+/************************************************************************/
+
+/** Gets the ADBC driver initialization function for the current thread.
+ */
+AdbcDriverInitFunc GDALGetAdbcDriverInitFunc()
+{
+    return tlAdbcDriverInitFunc;
+}

gcore/gdal_adbc.h

@@ -0,0 +1,41 @@
+/******************************************************************************
+ * Name:     gdal_adbc.h
+ * Project:  GDAL Core
+ * Purpose:  GDAL Core ADBC related declarations.
+ * Author:   Even Rouault <even dot rouault at spatialys.com>
+ *
+ ******************************************************************************
+ * Copyright (c) 2024, Even Rouault <even dot rouault at spatialys.com>
+ *
+ * SPDX-License-Identifier: MIT
+ ****************************************************************************/
+
+#ifndef GDAL_ADBC_H_INCLUDED
+#define GDAL_ADBC_H_INCLUDED
+
+/**
+ * \file gdal_adbc.h
+ *
+ * C GDAL entry points for Arrow Database Connectivity (ADBC)
+ *
+ * This header can only be used if the ADBC macro is defined, indicating that
+ * the abdc.h header has already been included before.
+ *
+ * \since GDAL 3.11
+ */
+
+#include "cpl_port.h"
+
+#ifdef ADBC
+
+CPL_C_START
+
+void CPL_DLL GDALSetAdbcDriverInitFunc(AdbcDriverInitFunc init_func);
+
+AdbcDriverInitFunc CPL_DLL GDALGetAdbcDriverInitFunc(void);
+
+CPL_C_END
+
+#endif
+
+#endif

ogr/ogrsf_frmts/adbc/ogradbcdataset.cpp

@@ -15,6 +15,7 @@
 #include "ogr_mem.h"
 #include "ogr_p.h"
 #include "cpl_json.h"
+#include "gdal_adbc.h"
 
 /************************************************************************/
 /*                           ~OGRADBCDataset()                          */
@@ -182,7 +183,28 @@ bool OGRADBCDataset::Open(const GDALOpenInfo *poOpenInfo)
     const bool bIsParquet = OGRADBCDriverIsParquet(poOpenInfo) ||
                             EQUAL(CPLGetExtension(pszFilename), "parquet");
     const bool bIsPostgreSQL = STARTS_WITH(pszFilename, "postgresql://");
-    if (!pszADBCDriverName)
+
+    AdbcDriverInitFunc pfnDriverInitFunc = GDALGetAdbcDriverInitFunc();
+    if (pfnDriverInitFunc && pszADBCDriverName)
+    {
+        CPLError(CE_Failure, CPLE_NotSupported,
+                 "Both a AdbcDriverInitFunc and ADBC_DRIVER open option are "
+                 "defined. This is not supported");
+        return false;
+    }
+
+    if (pfnDriverInitFunc)
+    {
+        if (AdbcDriverManagerDatabaseSetInitFunc(&m_database, pfnDriverInitFunc,
+                                                 error) != ADBC_STATUS_OK)
+        {
+            CPLError(CE_Failure, CPLE_AppDefined,
+                     "AdbcDriverManagerDatabaseSetInitFunc() failed: %s",
+                     error.message());
+            return false;
+        }
+    }
+    else if (!pszADBCDriverName)
     {
         if (bIsDuckDB || bIsParquet)
         {
@@ -210,15 +232,17 @@ bool OGRADBCDataset::Open(const GDALOpenInfo *poOpenInfo)
         }
     }
 
-    if (AdbcDatabaseSetOption(&m_database, "driver", pszADBCDriverName,
+    if (pszADBCDriverName &&
+        AdbcDatabaseSetOption(&m_database, "driver", pszADBCDriverName,
                               error) != ADBC_STATUS_OK)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "AdbcDatabaseSetOption() failed: %s", error.message());
         return false;
     }
 
-    if (bIsDuckDB || bIsParquet || strstr(pszADBCDriverName, "duckdb"))
+    if (pszADBCDriverName &&
+        (bIsDuckDB || bIsParquet || strstr(pszADBCDriverName, "duckdb")))
     {
         if (AdbcDatabaseSetOption(&m_database, "entrypoint", "duckdb_adbc_init",
                                   error) != ADBC_STATUS_OK)