Add the backup data file writer C++ class.
diff --git a/include/utils/backup_helpers.h b/include/utils/backup_helpers.h
index 73b9989..0c59fec 100644
--- a/include/utils/backup_helpers.h
+++ b/include/utils/backup_helpers.h
@@ -25,8 +25,28 @@
int back_up_files(int oldSnapshotFD, int oldDataStream, int newSnapshotFD,
char const* fileBase, char const* const* files, int fileCount);
+// the sizes of all of these match.
+typedef struct {
+ int type; // == APP_MAGIC_V1
+ int packageLen; // length of the name of the package that follows, not including the null.
+ int cookie;
+} app_header_v1;
+
+typedef struct {
+ int type; // ENTITY_MAGIC_V1
+ int keyLen; // length of the key name, not including the null terminator
+ int dataSize; // size of the data, not including the padding
+} entity_header_v1;
+
+typedef struct {
+ int type; // FOOTER_MAGIC_V1
+ int entityCount; // the number of entities that were written
+ int cookie;
+} app_footer_v1;
+
+
/**
- * Reads the data.
+ * Writes the data.
*
* If an error occurs, it poisons this object and all write calls will fail
* with the error that occurred.
@@ -38,12 +58,12 @@
// does not close fd
~BackupDataWriter();
- status_t WriteAppHeader(const String8& packageName);
+ status_t WriteAppHeader(const String8& packageName, int cookie);
status_t WriteEntityHeader(const String8& key, size_t dataSize);
status_t WriteEntityData(const void* data, size_t size);
- status_t WriteAppFooter();
+ status_t WriteAppFooter(int cookie);
private:
explicit BackupDataWriter();
@@ -55,6 +75,44 @@
int m_entityCount;
};
+/**
+ * Reads the data.
+ *
+ * If an error occurs, it poisons this object and all write calls will fail
+ * with the error that occurred.
+ */
+class BackupDataReader
+{
+public:
+ BackupDataReader(int fd);
+ // does not close fd
+ ~BackupDataReader();
+
+ status_t Status();
+ status_t ReadNextHeader();
+
+ status_t ReadAppHeader(String8* packageName, int* cookie);
+ bool HasEntities();
+ status_t ReadEntityHeader(String8* key, size_t* dataSize);
+ status_t ReadEntityData(void* data, size_t size);
+ status_t ReadAppFooter(int* cookie);
+
+private:
+ explicit BackupDataReader();
+ status_t skip_padding();
+
+ int m_fd;
+ status_t m_status;
+ ssize_t m_pos;
+ int m_entityCount;
+ union {
+ int type;
+ app_header_v1 app;
+ entity_header_v1 entity;
+ app_footer_v1 footer;
+ } m_header;
+};
+
#define TEST_BACKUP_HELPERS 0
#if TEST_BACKUP_HELPERS
@@ -62,6 +120,7 @@
int backup_helper_test_four();
int backup_helper_test_files();
int backup_helper_test_data_writer();
+int backup_helper_test_data_reader();
#endif
} // namespace android