From 2d8aaf95a6c1fd8c27af9c8293f57ea5ba148283 Mon Sep 17 00:00:00 2001
From: Will Ayd <william.ayd@icloud.com>
Date: Mon, 15 Sep 2025 15:14:50 -0400
Subject: [PATCH 1/3] GH-46147: [C++] Implement GCS support in Meson

---
 ci/scripts/cpp_build.sh        |  1 -
 cpp/src/arrow/meson.build      | 47 +++++++++++++++++++++++++++++++++-
 cpp/src/arrow/util/meson.build |  2 +-
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/ci/scripts/cpp_build.sh b/ci/scripts/cpp_build.sh
index eb4291bafbd..2f02f8c1496 100755
--- a/ci/scripts/cpp_build.sh
+++ b/ci/scripts/cpp_build.sh
@@ -146,7 +146,6 @@ if [ "${ARROW_USE_MESON:-OFF}" = "ON" ]; then
     --pkg-config-path="${CONDA_PREFIX}/lib/pkgconfig/" \
     -Dauto_features=enabled \
     -Dfuzzing=disabled \
-    -Dgcs=disabled \
     -Ds3=disabled \
     . \
     ${source_dir}
diff --git a/cpp/src/arrow/meson.build b/cpp/src/arrow/meson.build
index 8887da9174c..bc69583698d 100644
--- a/cpp/src/arrow/meson.build
+++ b/cpp/src/arrow/meson.build
@@ -410,7 +410,52 @@ if needs_filesystem
     endif
 
     if needs_gcs
-        error('gcs filesystem support is not yet implemented in Meson')
+        arrow_filesystem_srcs += files(
+            'filesystem/gcsfs.cc',
+            'filesystem/gcsfs_internal.cc',
+        )
+
+        gcs_common_dep = dependency(
+            'google_cloud_cpp_common',
+            allow_fallback: false,
+            required: false,
+        )
+        gcs_rest_internal_dep = dependency(
+            'google_cloud_cpp_rest_internal',
+            allow_fallback: false,
+            required: false,
+        )
+        gcs_storage_dep = dependency(
+            'google_cloud_cpp_storage',
+            allow_fallback: false,
+            required: false,
+        )
+
+        if not (gcs_common_dep.found()
+    and gcs_rest_internal_dep.found()
+    and gcs_storage_dep.found()
+)
+            error(
+                '''
+The Arrow Meson configuration requires that google_cloud_cpp_common,
+google_cloud_cpp_rest_internal, and google_cloud_cpp_storage be provided
+by the host system, but these could not be found. Subproject fallback is
+not implemented.
+
+Ensure that you have all of these components installed on your system, or
+disable Arrow gcs support with -Dgcs=disabled.
+            ''',
+            )
+        endif
+
+        gcs_dep = declare_dependency(
+            dependencies: [
+                gcs_common_dep,
+                gcs_rest_internal_dep,
+                gcs_storage_dep,
+            ],
+        )
+        arrow_filesystem_deps += [gcs_dep]
     endif
 
     if needs_hdfs
diff --git a/cpp/src/arrow/util/meson.build b/cpp/src/arrow/util/meson.build
index bce4de21b94..0c49abc9b9f 100644
--- a/cpp/src/arrow/util/meson.build
+++ b/cpp/src/arrow/util/meson.build
@@ -54,7 +54,7 @@ conf_data.set('ARROW_PARQUET', needs_parquet)
 conf_data.set('ARROW_SUBSTRAIT', needs_substrait)
 conf_data.set('ARROW_AZURE', false)
 conf_data.set('ARROW_ENABLE_THREADING', true)
-conf_data.set('ARROW_GCS', false)
+conf_data.set('ARROW_GCS', needs_gcs)
 conf_data.set('ARROW_HDFS', false)
 conf_data.set('ARROW_S3', false)
 conf_data.set('ARROW_USE_GLOG', false)

From 03fe7502778ed71994c112af9f6c258cebed133c Mon Sep 17 00:00:00 2001
From: Will Ayd <william.ayd@icloud.com>
Date: Thu, 18 Sep 2025 12:51:40 -0400
Subject: [PATCH 2/3] Add absl_time_zone_dep to GCS

---
 cpp/src/arrow/meson.build | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cpp/src/arrow/meson.build b/cpp/src/arrow/meson.build
index bc69583698d..36d8d62a3db 100644
--- a/cpp/src/arrow/meson.build
+++ b/cpp/src/arrow/meson.build
@@ -455,7 +455,9 @@ disable Arrow gcs support with -Dgcs=disabled.
                 gcs_storage_dep,
             ],
         )
-        arrow_filesystem_deps += [gcs_dep]
+
+        absl_time_zone_dep = dependency('absl_time_zone')
+        arrow_filesystem_deps += [gcs_dep, absl_time_zone_dep]
     endif
 
     if needs_hdfs

From 2fc1541e4243d9d921e49addaba4c8473074ebb5 Mon Sep 17 00:00:00 2001
From: Will Ayd <william.ayd@icloud.com>
Date: Thu, 18 Sep 2025 16:21:33 -0400
Subject: [PATCH 3/3] Try without explicit absl_time_zone dependency

---
 cpp/src/arrow/meson.build | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/cpp/src/arrow/meson.build b/cpp/src/arrow/meson.build
index 36d8d62a3db..43050aa1597 100644
--- a/cpp/src/arrow/meson.build
+++ b/cpp/src/arrow/meson.build
@@ -456,8 +456,7 @@ disable Arrow gcs support with -Dgcs=disabled.
             ],
         )
 
-        absl_time_zone_dep = dependency('absl_time_zone')
-        arrow_filesystem_deps += [gcs_dep, absl_time_zone_dep]
+        arrow_filesystem_deps += [gcs_dep]
     endif
 
     if needs_hdfs