FileSystemSyncAccessHandle::{read,write}'s option should be optional

https://bugs.webkit.org/show_bug.cgi?id=249631
rdar://103541719

Reviewed by Justin Michaud.

The current FileSystemSyncAccessHandle::{read,write} implementation has a bug that `options` parameter is specified as mandatory.
As a result, these APIs throw errors because it is using `read` / `write` functions without options.
This patch fixes the implementation to make them optional.

When optional `at` is not found, then the behavior is using the current file position's cursor. Thus, we just skip seekFile if
it is not specified.

* LayoutTests/storage/filesystemaccess/resources/sync-access-handle-read-write.js:
(write):
(read):
(async test):
* LayoutTests/storage/filesystemaccess/sync-access-handle-read-write-worker-expected.txt:
* Source/WebCore/Modules/filesystemaccess/FileSystemSyncAccessHandle.cpp:
(WebCore::FileSystemSyncAccessHandle::read):
(WebCore::FileSystemSyncAccessHandle::write):
* Source/WebCore/Modules/filesystemaccess/FileSystemSyncAccessHandle.h:
* Source/WebCore/Modules/filesystemaccess/FileSystemSyncAccessHandle.idl:

Canonical link: https://commits.webkit.org/258160@main

LayoutTests/storage/filesystemaccess/resources/sync-access-handle-read-write.js

@@ -24,15 +24,21 @@ function stringToArrayBuffer(string)
 function write(accessHandle, offset, text)
 {
     writeBuffer = stringToArrayBuffer(text);
-    writeSize = accessHandle.write(writeBuffer, { "at" : offset });
+    if (offset == null)
+        writeSize = accessHandle.write(writeBuffer);
+    else
+        writeSize = accessHandle.write(writeBuffer, { "at" : offset });
     shouldBe("writeSize", "writeBuffer.byteLength");
     return writeSize;
 }
 
 function read(accessHandle, offset, size, expectedString)
 {
     readBuffer = new ArrayBuffer(size);
-    readSize = accessHandle.read(readBuffer, { "at": offset });
+    if (offset == null)
+        readSize = accessHandle.read(readBuffer);
+    else
+        readSize = accessHandle.read(readBuffer, { "at": offset });
     shouldBe("readSize", "readBuffer.byteLength");
     if (expectedString) {
         readText = arrayBufferToString(readBuffer);
@@ -60,6 +66,11 @@ async function test()
         read(accessHandle, 0, totalWriteSize, "This is first sentence.This is second sentence.");
 
         // Wrong offset to read and write.
+        totalReadSize = totalWriteSize;
+        // File cursor should be updated by last read(), so the next write() should append to file.
+        totalWriteSize += write(accessHandle, null, "This is third sentence.");
+        read(accessHandle, 0, totalReadSize, "This is first sentence.This is second sentence.");
+        read(accessHandle, null, totalWriteSize - totalReadSize, "This is third sentence.");
         shouldThrow("accessHandle.read(new ArrayBuffer(1), { \"at\" : Number.MAX_SAFE_INTEGER })");
         shouldThrow("accessHandle.write(new ArrayBuffer(1), { \"at\" : Number.MAX_SAFE_INTEGER })");
 

LayoutTests/storage/filesystemaccess/sync-access-handle-read-write-worker-expected.txt

@@ -14,6 +14,11 @@ PASS [Worker] readSize is readBuffer.byteLength
 PASS [Worker] readText is "This is second sentence."
 PASS [Worker] readSize is readBuffer.byteLength
 PASS [Worker] readText is "This is first sentence.This is second sentence."
+PASS [Worker] writeSize is writeBuffer.byteLength
+PASS [Worker] readSize is readBuffer.byteLength
+PASS [Worker] readText is "This is first sentence.This is second sentence."
+PASS [Worker] readSize is readBuffer.byteLength
+PASS [Worker] readText is "This is third sentence."
 PASS [Worker] accessHandle.read(new ArrayBuffer(1), { "at" : Number.MAX_SAFE_INTEGER }) threw exception InvalidStateError: Failed to read at offset.
 PASS [Worker] accessHandle.write(new ArrayBuffer(1), { "at" : Number.MAX_SAFE_INTEGER }) threw exception InvalidStateError: Failed to write at offset.
 [Worker] test flush():

Source/WebCore/Modules/filesystemaccess/FileSystemSyncAccessHandle.cpp

@@ -211,11 +211,13 @@ ExceptionOr<unsigned long long> FileSystemSyncAccessHandle::read(BufferSource&&
     if (!m_pendingPromises.isEmpty())
         return Exception { InvalidStateError, "Access handle has unfinished operation"_s };
 
-    int result = FileSystem::seekFile(m_file.handle(), options.at, FileSystem::FileSeekOrigin::Beginning);
-    if (result == -1)
-        return Exception { InvalidStateError, "Failed to read at offset"_s };
+    if (options.at) {
+        int result = FileSystem::seekFile(m_file.handle(), options.at.value(), FileSystem::FileSeekOrigin::Beginning);
+        if (result == -1)
+            return Exception { InvalidStateError, "Failed to read at offset"_s };
+    }
 
-    result = FileSystem::readFromFile(m_file.handle(), buffer.mutableData(), buffer.length());
+    int result = FileSystem::readFromFile(m_file.handle(), buffer.mutableData(), buffer.length());
     if (result == -1)
         return Exception { InvalidStateError, "Failed to read from file"_s };
 
@@ -232,11 +234,13 @@ ExceptionOr<unsigned long long> FileSystemSyncAccessHandle::write(BufferSource&&
     if (!m_pendingPromises.isEmpty())
         return Exception { InvalidStateError, "Access handle has unfinished operation"_s };
 
-    int result = FileSystem::seekFile(m_file.handle(), options.at, FileSystem::FileSeekOrigin::Beginning);
-    if (result == -1)
-        return Exception { InvalidStateError, "Failed to write at offset"_s };
+    if (options.at) {
+        int result = FileSystem::seekFile(m_file.handle(), options.at.value(), FileSystem::FileSeekOrigin::Beginning);
+        if (result == -1)
+            return Exception { InvalidStateError, "Failed to write at offset"_s };
+    }
 
-    result = FileSystem::writeToFile(m_file.handle(), buffer.data(), buffer.length());
+    int result = FileSystem::writeToFile(m_file.handle(), buffer.data(), buffer.length());
     if (result == -1)
         return Exception { InvalidStateError, "Failed to write to file"_s };
 

Source/WebCore/Modules/filesystemaccess/FileSystemSyncAccessHandle.h

@@ -43,7 +43,7 @@ template<typename> class DOMPromiseDeferred;
 class FileSystemSyncAccessHandle : public ActiveDOMObject, public RefCounted<FileSystemSyncAccessHandle>, public CanMakeWeakPtr<FileSystemSyncAccessHandle> {
 public:
     struct FilesystemReadWriteOptions {
-        unsigned long long at;
+        std::optional<unsigned long long> at;
     };
 
     static Ref<FileSystemSyncAccessHandle> create(ScriptExecutionContext&, FileSystemFileHandle&, FileSystemSyncAccessHandleIdentifier, FileHandle&&);

Source/WebCore/Modules/filesystemaccess/FileSystemSyncAccessHandle.idl

@@ -33,8 +33,8 @@
     Promise<unsigned long long> getSize();
     Promise<undefined> flush();
     Promise<undefined> close();
-    unsigned long long read([AllowShared] (ArrayBufferView or ArrayBuffer) buffer, FilesystemReadWriteOptions options);
-    unsigned long long write([AllowShared] (ArrayBufferView or ArrayBuffer) buffer, FilesystemReadWriteOptions options);
+    unsigned long long read([AllowShared] (ArrayBufferView or ArrayBuffer) buffer, optional FilesystemReadWriteOptions options = {});
+    unsigned long long write([AllowShared] (ArrayBufferView or ArrayBuffer) buffer, optional FilesystemReadWriteOptions options = {});
 };
 
 dictionary FilesystemReadWriteOptions {