C.41 compliance: GCS factory constructor. (#5393)

Remove `GCS::init` in favor of a C.41-compliant factory constructor. Use
`struct GCSParameters` to store GCS-specific configuration parameters.
Remove `Status_GCSError`, and replace call sites with throws of
`GCSException`.

[sc-60072]

---
TYPE: IMPROVEMENT
DESC: C.41 constructor: `GCS`

test/src/unit-vfs.cc

@@ -822,7 +822,6 @@ TEST_CASE(
     "[gcs][credentials][impersonation]") {
   ThreadPool thread_pool(2);
   Config cfg = set_config_params(true);
-  GCS gcs;
   std::string impersonate_service_account, target_service_account;
   std::vector<std::string> delegates;
 
@@ -847,9 +846,7 @@ TEST_CASE(
 
   require_tiledb_ok(cfg.set(
       "vfs.gcs.impersonate_service_account", impersonate_service_account));
-
-  require_tiledb_ok(gcs.init(cfg, &thread_pool));
-
+  GCS gcs(&thread_pool, cfg);
   auto credentials = gcs.make_credentials({});
 
   // We are using an internal class only for inspection purposes.
@@ -869,16 +866,13 @@ TEST_CASE(
     "[gcs][credentials][service-account]") {
   ThreadPool thread_pool(2);
   Config cfg = set_config_params(true);
-  GCS gcs;
   // The content of the credentials does not matter; it does not get parsed
   // until it is used in an API request, which we are not doing.
   std::string service_account_key = "{\"foo\": \"bar\"}";
 
   require_tiledb_ok(
       cfg.set("vfs.gcs.service_account_key", service_account_key));
-
-  require_tiledb_ok(gcs.init(cfg, &thread_pool));
-
+  GCS gcs(&thread_pool, cfg);
   auto credentials = gcs.make_credentials({});
 
   // We are using an internal class only for inspection purposes.
@@ -895,7 +889,6 @@ TEST_CASE(
     "[gcs][credentials][service-account-and-impersonation]") {
   ThreadPool thread_pool(2);
   Config cfg = set_config_params(true);
-  GCS gcs;
   // The content of the credentials does not matter; it does not get parsed
   // until it is used in an API request, which we are not doing.
   std::string service_account_key = "{\"foo\": \"bar\"}";
@@ -905,9 +898,7 @@ TEST_CASE(
       cfg.set("vfs.gcs.service_account_key", service_account_key));
   require_tiledb_ok(cfg.set(
       "vfs.gcs.impersonate_service_account", impersonate_service_account));
-
-  require_tiledb_ok(gcs.init(cfg, &thread_pool));
-
+  GCS gcs(&thread_pool, cfg);
   auto credentials = gcs.make_credentials({});
 
   // We are using an internal class only for inspection purposes.
@@ -933,17 +924,13 @@ TEST_CASE(
     "[gcs][credentials][external-account]") {
   ThreadPool thread_pool(2);
   Config cfg = set_config_params(true);
-  GCS gcs;
   // The content of the credentials does not matter; it does not get parsed
   // until it is used in an API request, which we are not doing.
   std::string workload_identity_configuration = "{\"foo\": \"bar\"}";
-
   require_tiledb_ok(cfg.set(
       "vfs.gcs.workload_identity_configuration",
       workload_identity_configuration));
-
-  require_tiledb_ok(gcs.init(cfg, &thread_pool));
-
+  GCS gcs(&thread_pool, cfg);
   auto credentials = gcs.make_credentials({});
 
   // We are using an internal class only for inspection purposes.

tiledb/api/c_api/config/config_api_external.h

@@ -5,7 +5,7 @@
  *
  * The MIT License
  *
- * @copyright Copyright (c) 2023 TileDB, Inc.
+ * @copyright Copyright (c) 2023-2024 TileDB, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -455,6 +455,9 @@ TILEDB_EXPORT void tiledb_config_free(tiledb_config_t** config) TILEDB_NOEXCEPT;
  *    The maximum permissible delay between Azure netwwork request retry
  *    attempts, in milliseconds.
  *    **Default**: 60000
+ * - `vfs.gcs.endpoint` <br>
+ *    The GCS endpoint. <br>
+ *    **Default**: ""
  * - `vfs.gcs.project_id` <br>
  *    Set the GCS project ID to create new buckets to. Not required unless you
  *    are going to use the VFS to create buckets. <br>

tiledb/common/exception/status.h

@@ -310,10 +310,6 @@ inline Status Status_UtilsError(const std::string& msg) {
 inline Status Status_S3Error(const std::string& msg) {
   return {"[TileDB::S3] Error", msg};
 }
-/** Return a FS_GCS error class Status with a given message **/
-inline Status Status_GCSError(const std::string& msg) {
-  return {"[TileDB::GCS] Error", msg};
-}
 /** Return a FS_HDFS error class Status with a given message **/
 inline Status Status_HDFSError(const std::string& msg) {
   return {"[TileDB::HDFS] Error", msg};

tiledb/sm/cpp_api/config.h

@@ -1,13 +1,11 @@
 /**
  * @file   config.h
  *
- * @author Ravi Gaddipati
- *
  * @section LICENSE
  *
  * The MIT License
  *
- * @copyright Copyright (c) 2017-2023 TileDB, Inc.
+ * @copyright Copyright (c) 2017-2024 TileDB, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -627,6 +625,9 @@ class Config {
    *    The maximum permissible delay between Azure netwwork request retry
    *    attempts, in milliseconds.
    *    **Default**: 60000
+   * - `vfs.gcs.endpoint` <br>
+   *    The GCS endpoint. <br>
+   *    **Default**: ""
    * - `vfs.gcs.project_id` <br>
    *    Set the GCS project ID to create new buckets to. Not required unless you
    *    are going to use the VFS to create buckets. <br>