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+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "arrow/filesystem/filesystem.h"
+#include "arrow/util/uri.h"
+
+namespace arrow {
+namespace fs {
+
+struct GcsCredentials;
+
+/// Options for the GcsFileSystem implementation.
+struct ARROW_EXPORT GcsOptions {
+  std::shared_ptr<GcsCredentials> credentials;
+
+  std::string endpoint_override;
+  std::string scheme;
+  /// \brief Location to use for creating buckets.
+  std::string default_bucket_location;
+
+  /// \brief Default metadata for OpenOutputStream.
+  ///
+  /// This will be ignored if non-empty metadata is passed to OpenOutputStream.
+  std::shared_ptr<const KeyValueMetadata> default_metadata;
+
+  bool Equals(const GcsOptions& other) const;
+
+  /// \brief Initialize with Google Default Credentials
+  ///
+  /// Create options configured to use [Application Default Credentials][aip/4110]. The
+  /// details of this mechanism are too involved to describe here, but suffice is to say
+  /// that applications can override any defaults using an environment variable
+  /// (`GOOGLE_APPLICATION_CREDENTIALS`), and that the defaults work with most Google
+  /// Cloud Platform deployment environments (GCE, GKE, Cloud Run, etc.), and that have
+  /// the same behavior as the `gcloud` CLI tool on your workstation.
+  ///
+  /// \see https://cloud.google.com/docs/authentication
+  ///
+  /// [aip/4110]: https://google.aip.dev/auth/4110
+  static GcsOptions Defaults();
+
+  /// \brief Initialize with anonymous credentials
+  static GcsOptions Anonymous();
+
+  /// \brief Initialize with access token
+  ///
+  /// These credentials are useful when using an out-of-band mechanism to fetch access
+  /// tokens. Note that access tokens are time limited, you will need to manually refresh
+  /// the tokens created by the out-of-band mechanism.
+  static GcsOptions FromAccessToken(const std::string& access_token,
+                                    std::chrono::system_clock::time_point expiration);
+
+  /// \brief Initialize with service account impersonation
+  ///
+  /// Service account impersonation allows one principal (a user or service account) to
+  /// impersonate a service account. It requires that the calling principal has the
+  /// necessary permissions *on* the service account.
+  static GcsOptions FromImpersonatedServiceAccount(
+      const GcsCredentials& base_credentials, const std::string& target_service_account);
+
+  /// Creates service account credentials from a JSON object in string form.
+  ///
+  /// The @p json_object  is expected to be in the format described by [aip/4112]. Such an
+  /// object contains the identity of a service account, as well as a private key that can
+  /// be used to sign tokens, showing the caller was holding the private key.
+  ///
+  /// In GCP one can create several "keys" for each service account, and these keys are
+  /// downloaded as a JSON "key file". The contents of such a file are in the format
+  /// required by this function. Remember that key files and their contents should be
+  /// treated as any other secret with security implications, think of them as passwords
+  /// (because they are!), don't store them or output them where unauthorized persons may
+  /// read them.
+  ///
+  /// Most applications should probably use default credentials, maybe pointing them to a
+  /// file with these contents. Using this function may be useful when the json object is
+  /// obtained from a Cloud Secret Manager or a similar service.
+  ///
+  /// [aip/4112]: https://google.aip.dev/auth/4112
+  static GcsOptions FromServiceAccountCredentials(const std::string& json_object);
+
+  /// Initialize from URIs such as "gs://bucket/object".
+  static Result<GcsOptions> FromUri(const arrow::internal::Uri& uri,
+                                    std::string* out_path);
+  static Result<GcsOptions> FromUri(const std::string& uri, std::string* out_path);
+};
+
+/// \brief GCS-backed FileSystem implementation.
+///
+/// GCS (Google Cloud Storage - https://cloud.google.com/storage) is a scalable object
+/// storage system for any amount of data. The main abstractions in GCS are buckets and
+/// objects. A bucket is a namespace for objects, buckets can store any number of objects,
+/// tens of millions and even billions is not uncommon.  Each object contains a single
+/// blob of data, up to 5TiB in size.  Buckets are typically configured to keep a single
+/// version of each object, but versioning can be enabled. Versioning is important because
+/// objects are immutable, once created one cannot append data to the object or modify the
+/// object data in any way.
+///
+/// GCS buckets are in a global namespace, if a Google Cloud customer creates a bucket
+/// named `foo` no other customer can create a bucket with the same name. Note that a
+/// principal (a user or service account) may only list the buckets they are entitled to,
+/// and then only within a project. It is not possible to list "all" the buckets.
+///
+/// Within each bucket objects are in flat namespace. GCS does not have folders or
+/// directories. However, following some conventions it is possible to emulate
+/// directories. To this end, this class:
+///
+/// - All buckets are treated as directories at the "root"
+/// - Creating a root directory results in a new bucket being created, this may be slower
+///   than most GCS operations.
+/// - The class creates marker objects for a directory, using a metadata attribute to
+///   annotate the file.
+/// - GCS can list all the objects with a given prefix, this is used to emulate listing
+///   of directories.
+/// - In object lists GCS can summarize all the objects with a common prefix as a single
+///   entry, this is used to emulate non-recursive lists. Note that GCS list time is
+///   proportional to the number of objects in the prefix. Listing recursively takes
+///   almost the same time as non-recursive lists.
+///
+class ARROW_EXPORT GcsFileSystem : public FileSystem {
+ public:
+  ~GcsFileSystem() override = default;
+
+  std::string type_name() const override;
+
+  bool Equals(const FileSystem& other) const override;
+
+  Result<FileInfo> GetFileInfo(const std::string& path) override;
+  Result<FileInfoVector> GetFileInfo(const FileSelector& select) override;
+
+  Status CreateDir(const std::string& path, bool recursive) override;
+
+  Status DeleteDir(const std::string& path) override;
+
+  Status DeleteDirContents(const std::string& path, bool missing_dir_ok = false) override;
+
+  /// This is not implemented in GcsFileSystem, as it would be too dangerous.
+  Status DeleteRootDirContents() override;
+
+  Status DeleteFile(const std::string& path) override;
+
+  Status Move(const std::string& src, const std::string& dest) override;
+
+  Status CopyFile(const std::string& src, const std::string& dest) override;
+
+  Result<std::shared_ptr<io::InputStream>> OpenInputStream(
+      const std::string& path) override;
+  Result<std::shared_ptr<io::InputStream>> OpenInputStream(const FileInfo& info) override;
+
+  Result<std::shared_ptr<io::RandomAccessFile>> OpenInputFile(
+      const std::string& path) override;
+  Result<std::shared_ptr<io::RandomAccessFile>> OpenInputFile(
+      const FileInfo& info) override;
+
+  Result<std::shared_ptr<io::OutputStream>> OpenOutputStream(
+      const std::string& path,
+      const std::shared_ptr<const KeyValueMetadata>& metadata) override;
+
+  ARROW_DEPRECATED(
+      "Deprecated. "
+      "OpenAppendStream is unsupported on the GCS FileSystem.")
+  Result<std::shared_ptr<io::OutputStream>> OpenAppendStream(
+      const std::string& path,
+      const std::shared_ptr<const KeyValueMetadata>& metadata) override;
+
+  /// Create a GcsFileSystem instance from the given options.
+  static std::shared_ptr<GcsFileSystem> Make(
+      const GcsOptions& options, const io::IOContext& = io::default_io_context());
+
+ private:
+  explicit GcsFileSystem(const GcsOptions& options, const io::IOContext& io_context);
+
+  class Impl;
+  std::shared_ptr<Impl> impl_;
+};
+
+}  // namespace fs
+}  // namespace arrow