[sql] Recover Favicons v5 databases, with more recovery automation.

sql/test/test_helpers.cc

Index: sql/test/test_helpers.cc
diff --git a/sql/test/test_helpers.cc b/sql/test/test_helpers.cc
index de3e8f8e0ed730629c2094fea84ce2c623190933..5438bd654b60d256848003727824be92ae258550 100644
--- a/sql/test/test_helpers.cc
+++ b/sql/test/test_helpers.cc
@@ -21,11 +21,73 @@ size_t CountSQLItemsOfType(sql::Connection* db, const char* type) {
   return s.ColumnInt(0);
 }
 
+// Helper for reading a number from the SQLite header.
+// See net/base/big_endian.h.
+unsigned ReadBigEndian(unsigned char* buf, size_t bytes) {
+  unsigned r = buf[0];
+  for (size_t i = 1; i < bytes; i++) {
+    r <<= 8;
+    r |= buf[i];
+  }
+  return r;
+}
+
+// Helper for writing a number to the SQLite header.
+void WriteBigEndian(unsigned val, unsigned char* buf, size_t bytes) {
+  for (size_t i = 0; i < bytes; i++) {
+    buf[bytes - i - 1] = (val & 0xFF);
+    val >>= 8;
+  }
+}
+
 }  // namespace
 
 namespace sql {
 namespace test {
 
+bool CorruptSizeInHeader(const base::FilePath& db_path) {
+  // See http://www.sqlite.org/fileformat.html#database_header
+  const size_t kHeaderSize = 100;
+  const size_t kPageSizeOffset = 16;
+  const size_t kFileChangeCountOffset = 24;
+  const size_t kPageCountOffset = 28;
+  const size_t kVersionValidForOffset = 92;  // duplicate kFileChangeCountOffset
+
+  unsigned char header[kHeaderSize];
+
+  file_util::ScopedFILE file(file_util::OpenFile(db_path, "rb+"));
+  if (!file.get())
+    return false;
+
+  if (0 != fseek(file.get(), 0, SEEK_SET))
+    return false;
+  if (1u != fread(header, sizeof(header), 1, file.get()))
+    return false;
+
+  int64 db_size = 0;
+  if (!file_util::GetFileSize(db_path, &db_size))
+    return false;
+
+  const unsigned page_size = ReadBigEndian(header + kPageSizeOffset, 2);
+
+  // One larger than the expected size.
+  const unsigned page_count = (db_size + page_size) / page_size;
+  WriteBigEndian(page_count, header + kPageCountOffset, 4);
+
+  // Update change count so outstanding readers know the info changed.
+  // Both spots must match for the page count to be considered valid.
+  unsigned change_count = ReadBigEndian(header + kFileChangeCountOffset, 4);
+  WriteBigEndian(change_count + 1, header + kFileChangeCountOffset, 4);
+  WriteBigEndian(change_count + 1, header + kVersionValidForOffset, 4);
+
+  if (0 != fseek(file.get(), 0, SEEK_SET))
+    return false;
+  if (1u != fwrite(header, sizeof(header), 1, file.get()))
+    return false;
+
+  return true;
+}
+
 size_t CountSQLTables(sql::Connection* db) {
   return CountSQLItemsOfType(db, "table");
 }
@@ -91,5 +153,14 @@ bool CreateDatabaseFromSQL(const base::FilePath& db_path,
   return db.Execute(sql.c_str());
 }
 
+std::string IntegrityCheck(sql::Connection* db) {
+  sql::Statement statement(db->GetUniqueStatement("PRAGMA integrity_check"));
+
+  // SQLite should always return a row of data.
+  EXPECT_TRUE(statement.Step());
+
+  return statement.ColumnString(0);
+}
+
 }  // namespace test
 }  // namespace sql