From eb4c1302abab231b9078ae67736cc0412a724d4f Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Wed, 20 Aug 2025 14:39:17 +0000
Subject: [PATCH 1/9] making  crc32c as default

---
 .../lib/google/cloud/storage/bucket.rb        |  1 +
 .../test/google/cloud/storage/bucket_test.rb  | 45 ++++++++++++++++++-
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/google-cloud-storage/lib/google/cloud/storage/bucket.rb b/google-cloud-storage/lib/google/cloud/storage/bucket.rb
index ca8461354bb7..b55485149875 100644
--- a/google-cloud-storage/lib/google/cloud/storage/bucket.rb
+++ b/google-cloud-storage/lib/google/cloud/storage/bucket.rb
@@ -1805,6 +1805,7 @@ def create_file file,
           path ||= file.path if file.respond_to? :path
           path ||= file if file.is_a? String
           raise ArgumentError, "must provide path" if path.nil?
+          checksum = :crc32c if checksum == nil && crc32c.nil? && md5.nil?
           crc32c = crc32c_for file, checksum, crc32c
           md5 = md5_for file, checksum, md5
 
diff --git a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
index 203e423467e5..b32f6a23c0e0 100644
--- a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
@@ -101,6 +101,40 @@
     _(bucket_complete.autoclass_enabled).must_equal bucket_autoclass_enabled
     _(bucket_complete.autoclass_terminal_storage_class).must_equal bucket_autoclass_terminal_storage_class
   end
+  
+  it "creates a file with checksum: :crc32c by default" do
+    new_file_name = random_file_path
+
+    Tempfile.open ["google-cloud", ".txt"] do |tmpfile|
+      tmpfile.write "Hello world!"
+      tmpfile.rewind
+
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for tmpfile
+
+      mock = Minitest::Mock.new
+      mock.expect :insert_object, create_file_gapi(bucket.name, new_file_name),
+        [bucket.name, empty_file_gapi(crc32c: crc32c)], **insert_object_args(name: new_file_name, upload_source: tmpfile, options: {retries: 0})
+
+      bucket.service.mocked_service = mock
+      bucket.create_file tmpfile, new_file_name
+
+      mock.verify
+    end
+  end
+
+  it "creates a file with a StringIO and checksum: :crc32c by default" do
+    new_file_name = random_file_path
+    new_file_contents = StringIO.new "Hello world"
+    mock = Minitest::Mock.new
+    mock.expect :insert_object, create_file_gapi(bucket.name, new_file_name),
+      [bucket.name, empty_file_gapi(crc32c: "crUfeA==")], **insert_object_args(name: new_file_name, upload_source: new_file_contents, options: {retries: 0})
+
+    bucket.service.mocked_service = mock
+
+    bucket.create_file new_file_contents, new_file_name
+
+    mock.verify
+  end
 
   it "returns frozen cors" do
     bucket_complete.cors.each do |cors|
@@ -597,7 +631,7 @@
     Tempfile.create ["google-cloud", ".txt"] do |tmpfile|
       mock = Minitest::Mock.new
       mock.expect :insert_object, create_file_gapi(bucket_user_project.name, new_file_name),
-        [bucket.name, empty_file_gapi], **insert_object_args(name: new_file_name, upload_source: tmpfile, user_project: "test", options: {retries: 0})
+        [bucket.name, empty_file_gapi(crc32c: "AAAAAA==")], **insert_object_args(name: new_file_name, upload_source: tmpfile, user_project: "test", options: {retries: 0})
 
       bucket_user_project.service.mocked_service = mock
 
@@ -610,7 +644,7 @@
 
   it "creates an file with a StringIO" do
     new_file_name = random_file_path
-    new_file_contents = StringIO.new
+    new_file_contents = StringIO.new("Hello world")
 
     mock = Minitest::Mock.new
     mock.expect :insert_object, create_file_gapi(bucket.name, new_file_name),
@@ -1417,6 +1451,13 @@ def empty_file_gapi cache_control: nil, content_disposition: nil,
                       content_type: nil, crc32c: nil, md5: nil, metadata: nil,
                       storage_class: nil, temporary_hold: nil,
                       event_based_hold: nil
+
+  # new_file_contents = StringIO.new
+  # Set crc32c if both md5 and crc32c are not provided
+  if md5.nil? && crc32c.nil?
+    crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for(StringIO.new("Hello world"))
+  end
+
     params = {
       cache_control: cache_control, content_type: content_type,
       content_disposition: content_disposition, md5_hash: md5,

From a5bb38559c6b328df67dc22c20e05fe2684435b7 Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Wed, 20 Aug 2025 14:53:12 +0000
Subject: [PATCH 2/9] refactoring

---
 google-cloud-storage/lib/google/cloud/storage/bucket.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/google-cloud-storage/lib/google/cloud/storage/bucket.rb b/google-cloud-storage/lib/google/cloud/storage/bucket.rb
index b55485149875..e0cd98b00300 100644
--- a/google-cloud-storage/lib/google/cloud/storage/bucket.rb
+++ b/google-cloud-storage/lib/google/cloud/storage/bucket.rb
@@ -1805,7 +1805,7 @@ def create_file file,
           path ||= file.path if file.respond_to? :path
           path ||= file if file.is_a? String
           raise ArgumentError, "must provide path" if path.nil?
-          checksum = :crc32c if checksum == nil && crc32c.nil? && md5.nil?
+          checksum = :crc32c if checksum.nil? && crc32c.nil? && md5.nil?
           crc32c = crc32c_for file, checksum, crc32c
           md5 = md5_for file, checksum, md5
 

From 9000bdb7327238746db8c1b028be45c1b8071cd6 Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Thu, 21 Aug 2025 09:06:32 +0000
Subject: [PATCH 3/9] modifying tests

---
 .../test/google/cloud/storage/bucket_test.rb                | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
index b32f6a23c0e0..cf7861a4349a 100644
--- a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
@@ -127,7 +127,7 @@
     new_file_contents = StringIO.new "Hello world"
     mock = Minitest::Mock.new
     mock.expect :insert_object, create_file_gapi(bucket.name, new_file_name),
-      [bucket.name, empty_file_gapi(crc32c: "crUfeA==")], **insert_object_args(name: new_file_name, upload_source: new_file_contents, options: {retries: 0})
+      [bucket.name, empty_file_gapi], **insert_object_args(name: new_file_name, upload_source: new_file_contents, options: {retries: 0})
 
     bucket.service.mocked_service = mock
 
@@ -629,9 +629,11 @@
     new_file_name = random_file_path
 
     Tempfile.create ["google-cloud", ".txt"] do |tmpfile|
+
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for tmpfile
       mock = Minitest::Mock.new
       mock.expect :insert_object, create_file_gapi(bucket_user_project.name, new_file_name),
-        [bucket.name, empty_file_gapi(crc32c: "AAAAAA==")], **insert_object_args(name: new_file_name, upload_source: tmpfile, user_project: "test", options: {retries: 0})
+        [bucket.name, empty_file_gapi(crc32c: crc32c)], **insert_object_args(name: new_file_name, upload_source: tmpfile, user_project: "test", options: {retries: 0})
 
       bucket_user_project.service.mocked_service = mock
 

From fae8845fe735b19565c46916f59d7856d95a60b7 Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Thu, 21 Aug 2025 09:11:45 +0000
Subject: [PATCH 4/9] removing commented line

---
 google-cloud-storage/test/google/cloud/storage/bucket_test.rb | 1 -
 1 file changed, 1 deletion(-)

diff --git a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
index cf7861a4349a..b200f79aff0e 100644
--- a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
@@ -1454,7 +1454,6 @@ def empty_file_gapi cache_control: nil, content_disposition: nil,
                       storage_class: nil, temporary_hold: nil,
                       event_based_hold: nil
 
-  # new_file_contents = StringIO.new
   # Set crc32c if both md5 and crc32c are not provided
   if md5.nil? && crc32c.nil?
     crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for(StringIO.new("Hello world"))

From 0147623c7fbc8a88e3cc3aca8c833e1f8ce89b0a Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Thu, 21 Aug 2025 11:23:21 +0000
Subject: [PATCH 5/9] modifying test cases

---
 .../lib/google/cloud/storage/file/verifier.rb |  2 ++
 .../cloud/storage/bucket_encryption_test.rb   |  4 +++
 .../test/google/cloud/storage/bucket_test.rb  |  8 +++---
 .../google/cloud/storage/lazy/bucket_test.rb  | 27 ++++++++++++++++++-
 4 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
index dcfefc6c616d..52bf667bf976 100644
--- a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
+++ b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
@@ -55,6 +55,7 @@ def self.md5_for local_file
                 ::Digest::MD5.file(f).base64digest
               end
             else # StringIO
+              (local_file = ::File.open Pathname(local_file)) unless local_file.respond_to? :rewind
               local_file.rewind
               md5 = ::Digest::MD5.base64digest local_file.read
               local_file.rewind
@@ -68,6 +69,7 @@ def self.crc32c_for local_file
                 ::Digest::CRC32c.file(f).base64digest
               end
             else # StringIO
+              (local_file = ::File.open Pathname(local_file)) unless local_file.respond_to? :rewind
               local_file.rewind
               crc32c = ::Digest::CRC32c.base64digest local_file.read
               local_file.rewind
diff --git a/google-cloud-storage/test/google/cloud/storage/bucket_encryption_test.rb b/google-cloud-storage/test/google/cloud/storage/bucket_encryption_test.rb
index ce617da110e6..7fe89376cfd2 100644
--- a/google-cloud-storage/test/google/cloud/storage/bucket_encryption_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/bucket_encryption_test.rb
@@ -131,6 +131,10 @@ def empty_file_gapi cache_control: nil, content_disposition: nil,
                       content_encoding: nil, content_language: nil,
                       content_type: nil, crc32c: nil, md5: nil, metadata: nil,
                       storage_class: nil
+     # Set crc32c if both md5 and crc32c are not provided
+    if md5.nil? && crc32c.nil?
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for(StringIO.new("Hello world"))
+    end
     params = {
       cache_control: cache_control, content_type: content_type,
       content_disposition: content_disposition, md5_hash: md5,
diff --git a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
index b200f79aff0e..7b9685f1dc08 100644
--- a/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/bucket_test.rb
@@ -1454,10 +1454,10 @@ def empty_file_gapi cache_control: nil, content_disposition: nil,
                       storage_class: nil, temporary_hold: nil,
                       event_based_hold: nil
 
-  # Set crc32c if both md5 and crc32c are not provided
-  if md5.nil? && crc32c.nil?
-    crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for(StringIO.new("Hello world"))
-  end
+    # Set crc32c if both md5 and crc32c are not provided
+    if md5.nil? && crc32c.nil?
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for(StringIO.new("Hello world"))
+    end
 
     params = {
       cache_control: cache_control, content_type: content_type,
diff --git a/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb b/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb
index c304f54b3838..f801118a5e54 100644
--- a/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb
@@ -244,6 +244,26 @@
       mock.verify
     end
   end
+  
+  it "creates a file with checksum: :crc32c by default" do
+    new_file_name = random_file_path
+
+    Tempfile.open ["google-cloud", ".txt"] do |tmpfile|
+      tmpfile.write "Hello world!"
+      tmpfile.rewind
+
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for tmpfile
+
+      mock = Minitest::Mock.new
+      mock.expect :insert_object, create_file_gapi(bucket.name, new_file_name),
+        [bucket.name, empty_file_gapi(crc32c: crc32c)], **insert_object_args(name: new_file_name, upload_source: tmpfile, options: {retries: 0})
+
+      bucket.service.mocked_service = mock
+      bucket.create_file tmpfile, new_file_name
+
+      mock.verify
+    end
+  end
 
   it "creates a file with attributes" do
     new_file_name = random_file_path
@@ -340,9 +360,10 @@
     new_file_name = random_file_path
 
     Tempfile.create ["google-cloud", ".txt"] do |tmpfile|
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for tmpfile
       mock = Minitest::Mock.new
       mock.expect :insert_object, create_file_gapi(bucket_user_project.name, new_file_name),
-        [bucket.name, empty_file_gapi], **insert_object_args(name: new_file_name, upload_source: tmpfile, user_project: "test", options: {retries: 0})
+        [bucket.name, empty_file_gapi(crc32c: crc32c)], **insert_object_args(name: new_file_name, upload_source: tmpfile, user_project: "test", options: {retries: 0})
 
       bucket_user_project.service.mocked_service = mock
 
@@ -1091,6 +1112,10 @@ def empty_file_gapi cache_control: nil, content_disposition: nil,
                       content_encoding: nil, content_language: nil,
                       content_type: nil, crc32c: nil, md5: nil, metadata: nil,
                       storage_class: nil
+    # Set crc32c if both md5 and crc32c are not provided
+    if md5.nil? && crc32c.nil?
+      crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for(StringIO.new("Hello world"))
+    end
     params = {
       cache_control: cache_control, content_type: content_type,
       content_disposition: content_disposition, md5_hash: md5,

From 13275c451929e7fb0617f6c0393af73e7aee0b98 Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Thu, 21 Aug 2025 17:30:28 +0530
Subject: [PATCH 6/9] Update bucket_test.rb

---
 .../test/google/cloud/storage/lazy/bucket_test.rb                | 1 -
 1 file changed, 1 deletion(-)

diff --git a/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb b/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb
index f801118a5e54..5f530634f16b 100644
--- a/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb
+++ b/google-cloud-storage/test/google/cloud/storage/lazy/bucket_test.rb
@@ -253,7 +253,6 @@
       tmpfile.rewind
 
       crc32c = Google::Cloud::Storage::File::Verifier.crc32c_for tmpfile
-
       mock = Minitest::Mock.new
       mock.expect :insert_object, create_file_gapi(bucket.name, new_file_name),
         [bucket.name, empty_file_gapi(crc32c: crc32c)], **insert_object_args(name: new_file_name, upload_source: tmpfile, options: {retries: 0})

From a89ca600de9b24b7b5eab792da974a837861fbf1 Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Thu, 16 Oct 2025 05:23:58 +0000
Subject: [PATCH 7/9] closing the intentionally opened file

---
 .../lib/google/cloud/storage/file/verifier.rb | 65 +++++++++++++------
 1 file changed, 44 insertions(+), 21 deletions(-)

diff --git a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
index 52bf667bf976..c6d3626f7a77 100644
--- a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
+++ b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
@@ -48,32 +48,55 @@ def self.verify_md5 gcloud_file, local_file
           def self.verify_crc32c gcloud_file, local_file
             gcloud_file.crc32c == crc32c_for(local_file)
           end
+          # Calculates MD5 digest using either file path or open stream.
+          def self.md5_for(local_file)
+            _digest_for(local_file, ::Digest::MD5)
+          end
 
-          def self.md5_for local_file
-            if local_file.respond_to? :to_path
-              ::File.open Pathname(local_file).to_path, "rb" do |f|
-                ::Digest::MD5.file(f).base64digest
-              end
-            else # StringIO
-              (local_file = ::File.open Pathname(local_file)) unless local_file.respond_to? :rewind
-              local_file.rewind
-              md5 = ::Digest::MD5.base64digest local_file.read
-              local_file.rewind
-              md5
-            end
+          # Calculates CRC32c digest using either file path or open stream.
+          def self.crc32c_for(local_file)
+            _digest_for(local_file, ::Digest::CRC32c)
           end
 
-          def self.crc32c_for local_file
-            if local_file.respond_to? :to_path
+          private
+
+          # @private
+          # Computes a base64-encoded digest for a local file or IO stream.
+          #
+          # This method handles two types of inputs for `local_file`:
+          # 1. A file path (String or Pathname): It efficiently streams the file
+          #    to compute the digest without loading the entire file into memory.
+          # 2. An IO-like stream (e.g., File, StringIO): It reads the stream's
+          #    content to compute the digest. The stream is rewound before and after
+          #    reading to ensure its position is not permanently changed.
+          #
+          # @param local_file [String, Pathname, IO] The local file path or IO
+          #   stream for which to compute the digest.
+          # @param digest_class [Class] The digest class to use for the
+          #   calculation (e.g., `Digest::MD5`). It must respond to `.file` and
+          #   `.base64digest`.
+          #
+          # @return [String] The base64-encoded digest of the file's content.
+          #
+          def self._digest_for(local_file, digest_class)
+            if local_file.respond_to?(:to_path)
+              # Case 1: Input is a file path (or Pathname). Use the safe block form.
               ::File.open Pathname(local_file).to_path, "rb" do |f|
-                ::Digest::CRC32c.file(f).base64digest
+                digest_class.file(f).base64digest
+              end
+            else
+              # Case 2: Input is an open stream (like File or StringIO).
+              file_to_close = nil
+              file_to_close = local_file = ::File.open(Pathname(local_file).to_path, "rb") unless local_file.respond_to?(:rewind)
+              begin
+                local_file.rewind
+                digest = digest_class.base64digest local_file.read
+                local_file.rewind
+                digest
+              ensure
+                # Only close the stream if we explicitly opened it 
+                file_to_close.close if file_to_close.respond_to?(:close) && !file_to_close.closed?
               end
-            else # StringIO
-              (local_file = ::File.open Pathname(local_file)) unless local_file.respond_to? :rewind
-              local_file.rewind
-              crc32c = ::Digest::CRC32c.base64digest local_file.read
-              local_file.rewind
-              crc32c
             end
           end
         end

From cbcbe63f15ed89cbc846a122d37f6542f978588d Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Thu, 16 Oct 2025 05:31:44 +0000
Subject: [PATCH 8/9] lintfix

---
 .../lib/google/cloud/storage/file/verifier.rb | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
index c6d3626f7a77..de807bd2dff8 100644
--- a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
+++ b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
@@ -48,18 +48,17 @@ def self.verify_md5 gcloud_file, local_file
           def self.verify_crc32c gcloud_file, local_file
             gcloud_file.crc32c == crc32c_for(local_file)
           end
+
           # Calculates MD5 digest using either file path or open stream.
-          def self.md5_for(local_file)
-            _digest_for(local_file, ::Digest::MD5)
+          def self.md5_for local_file
+            _digest_for local_file, ::Digest::MD5
           end
 
           # Calculates CRC32c digest using either file path or open stream.
-          def self.crc32c_for(local_file)
-            _digest_for(local_file, ::Digest::CRC32c)
+          def self.crc32c_for local_file
+            _digest_for local_file, ::Digest::CRC32c
           end
 
-          private
-
           # @private
           # Computes a base64-encoded digest for a local file or IO stream.
           #
@@ -78,8 +77,8 @@ def self.crc32c_for(local_file)
           #
           # @return [String] The base64-encoded digest of the file's content.
           #
-          def self._digest_for(local_file, digest_class)
-            if local_file.respond_to?(:to_path)
+          def self._digest_for local_file, digest_class
+            if local_file.respond_to? :to_path
               # Case 1: Input is a file path (or Pathname). Use the safe block form.
               ::File.open Pathname(local_file).to_path, "rb" do |f|
                 digest_class.file(f).base64digest
@@ -87,14 +86,17 @@ def self._digest_for(local_file, digest_class)
             else
               # Case 2: Input is an open stream (like File or StringIO).
               file_to_close = nil
-              file_to_close = local_file = ::File.open(Pathname(local_file).to_path, "rb") unless local_file.respond_to?(:rewind)
+              unless local_file.respond_to? :rewind
+                file_to_close = local_file = ::File.open Pathname(local_file).to_path,
+                                                         "rb"
+              end
               begin
                 local_file.rewind
                 digest = digest_class.base64digest local_file.read
                 local_file.rewind
                 digest
               ensure
-                # Only close the stream if we explicitly opened it 
+                # Only close the stream if we explicitly opened it
                 file_to_close.close if file_to_close.respond_to?(:close) && !file_to_close.closed?
               end
             end

From 6158a74c8803d5137938b92e396e0ad27e6d0f4e Mon Sep 17 00:00:00 2001
From: Shubhangi Singh <shubhangisin@google.com>
Date: Wed, 19 Nov 2025 04:46:16 +0000
Subject: [PATCH 9/9] refactor

---
 .../lib/google/cloud/storage/file/verifier.rb | 25 ++++++-------------
 1 file changed, 8 insertions(+), 17 deletions(-)

diff --git a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
index de807bd2dff8..c65f33bb7c08 100644
--- a/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
+++ b/google-cloud-storage/lib/google/cloud/storage/file/verifier.rb
@@ -78,27 +78,18 @@ def self.crc32c_for local_file
           # @return [String] The base64-encoded digest of the file's content.
           #
           def self._digest_for local_file, digest_class
-            if local_file.respond_to? :to_path
-              # Case 1: Input is a file path (or Pathname). Use the safe block form.
+
+            if local_file.respond_to?(:to_path) || local_file.is_a?(String)
+              # Case 1: Input is a file path (String, Pathname, or object that responds to :to_path).
               ::File.open Pathname(local_file).to_path, "rb" do |f|
                 digest_class.file(f).base64digest
               end
             else
-              # Case 2: Input is an open stream (like File or StringIO).
-              file_to_close = nil
-              unless local_file.respond_to? :rewind
-                file_to_close = local_file = ::File.open Pathname(local_file).to_path,
-                                                         "rb"
-              end
-              begin
-                local_file.rewind
-                digest = digest_class.base64digest local_file.read
-                local_file.rewind
-                digest
-              ensure
-                # Only close the stream if we explicitly opened it
-                file_to_close.close if file_to_close.respond_to?(:close) && !file_to_close.closed?
-              end
+              # Case 2: Input is an open stream (File or StringIO).
+              local_file.rewind
+              digest = digest_class.base64digest local_file.read
+              local_file.rewind
+              digest
             end
           end
         end