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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef SQL_STREAMING_BLOB_HANDLE_H_
#define SQL_STREAMING_BLOB_HANDLE_H_
#include "base/component_export.h"
#include "base/containers/span.h"
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/types/pass_key.h"
#include "sql/sqlite_result_code.h"
struct sqlite3_blob;
namespace sql {
class Database;
// Wraps a blob handle opened for streaming.
// See https://www.sqlite.org/c3ref/blob_open.html
// The handle will be closed when the instance is destroyed, or when an error
// occurs.
//
// Use `sql::Database::GetStreamingBlob()` to get an instance of this class.
// Callers are responsible for deleting this instance before attempting to
// close, poison, or raze the database. Note that even deleting an instance may
// run into an error which would cause the database's error callback to run.
class COMPONENT_EXPORT(SQL) StreamingBlobHandle {
public:
StreamingBlobHandle(
base::PassKey<sql::Database>,
sqlite3_blob* blob,
base::OnceCallback<void(SqliteResultCode, const char*)> done_callback);
~StreamingBlobHandle();
// Move is allowed to facilitate use with optional.
StreamingBlobHandle(StreamingBlobHandle&&);
StreamingBlobHandle& operator=(StreamingBlobHandle&&);
StreamingBlobHandle(const StreamingBlobHandle&) = delete;
StreamingBlobHandle& operator=(const StreamingBlobHandle&) = delete;
// These return true for success. If they fail once, calling them again
// will CHECK.
[[nodiscard]] bool Read(int offset, base::span<uint8_t> into);
[[nodiscard]] bool Write(int offset, base::span<const uint8_t> from);
// Returns the size of the blob in bytes. This will never be non-positive.
// After Read() or Write() has failed, calling this will CHECK.
int GetSize();
private:
// Closes `blob_handle_` if it's open, invoking `done_callback_`.
void Close();
// This handle is owned.
raw_ptr<sqlite3_blob> blob_handle_;
// This callback is invoked when the blob is closed, either due to an error or
// when `this` is destroyed normally. See `sql::Database::OnSqliteError()` for
// documentation of the parameters.
base::OnceCallback<void(SqliteResultCode, const char*)> done_callback_;
};
} // namespace sql
#endif // SQL_STREAMING_BLOB_HANDLE_H_
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