From ea2912f187cec8d426cfc2ca715b9a503355fa37 Mon Sep 17 00:00:00 2001
From: xunchang <xunchang@google.com>
Date: Sun, 17 Mar 2019 16:45:12 -0700
Subject: Create a FuseDataProvider base class

The fuse data provider for adb/sdcard shares common code and structures.
This cl creates a FuseDataProvider base class and provides
implementations for adb and sdcard.

In the follow cls, we can kill the provider_vtab struct; and also add
another implementation to parse a block map file and provides data.

Test: unit tests pass, sideload a package, apply a package from sdcard
Change-Id: If8311666a52a2e3c0fbae0ee9688fa6d01e4ad09
---
 fuse_sideload/include/fuse_provider.h | 73 +++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 fuse_sideload/include/fuse_provider.h

(limited to 'fuse_sideload/include/fuse_provider.h')

diff --git a/fuse_sideload/include/fuse_provider.h b/fuse_sideload/include/fuse_provider.h
new file mode 100644
index 000000000..672af0577
--- /dev/null
+++ b/fuse_sideload/include/fuse_provider.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed 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 <stdint.h>
+
+#include <string>
+
+#include <android-base/unique_fd.h>
+
+// This is the base class to read data from source and provide the data to FUSE.
+class FuseDataProvider {
+ public:
+  FuseDataProvider(android::base::unique_fd&& fd, uint64_t file_size, uint32_t block_size)
+      : fd_(std::move(fd)), file_size_(file_size), fuse_block_size_(block_size) {}
+
+  virtual ~FuseDataProvider() = default;
+
+  uint64_t file_size() const {
+    return file_size_;
+  }
+  uint32_t fuse_block_size() const {
+    return fuse_block_size_;
+  }
+
+  explicit operator bool() const {
+    return fd_ != -1;
+  }
+
+  // Reads |fetch_size| bytes data starting from |start_block|. Puts the result in |buffer|.
+  virtual bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
+                                    uint32_t start_block) const = 0;
+
+  virtual void Close() = 0;
+
+ protected:
+  FuseDataProvider() = default;
+
+  // The underlying source to read data from.
+  android::base::unique_fd fd_;
+  // Size in bytes of the file to read.
+  uint64_t file_size_ = 0;
+  // Block size passed to the fuse, this is different from the block size of the block device.
+  uint32_t fuse_block_size_ = 0;
+};
+
+// This class reads data from a file.
+class FuseFileDataProvider : public FuseDataProvider {
+ public:
+  FuseFileDataProvider(android::base::unique_fd&& fd, uint64_t file_size, uint32_t block_size)
+      : FuseDataProvider(std::move(fd), file_size, block_size) {}
+
+  FuseFileDataProvider(const std::string& path, uint32_t block_size);
+
+  bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
+                            uint32_t start_block) const override;
+
+  void Close() override;
+};
-- 
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