validate canons without yatest_common

1 files changed, 88 insertions, 0 deletions

diff --git a/library/cpp/deprecated/datafile/datafile.h b/library/cpp/deprecated/datafile/datafile.h
new file mode 100644
index 0000000000..a438baceca
--- /dev/null
+++ b/library/cpp/deprecated/datafile/datafile.h
@@ -0,0 +1,88 @@
+#pragma once
+
+#include "loadmode.h"
+
+#include <library/cpp/deprecated/mapped_file/mapped_file.h>
+
+#include <util/generic/vector.h>
+#include <util/system/file.h>
+#include <util/system/filemap.h>
+
+/** Simple helper that allows a file to be either mapped or read into malloc'ed memory.
+    This behaviour is controlled by EDataLoadMode enum defined in loadmode.h.
+    Unlike TBlob it provides Precharge() function and simple file size - based integrity check.
+
+    To use this code, inherit your class from TDataFile<TFileHeader>.
+    TFileHeader must be a pod-type structure with byte layout of the file header.
+    File must start with that header.
+    TFileHeader must have FileSize() member function that determines expected file size or
+    length of data that need to be read from the beginning of file.
+ */
+
+class TDataFileBase {
+protected:
+    TVector<char> MemData;
+    TMappedFile FileData;
+
+    const char* Start;
+    size_t Length;
+
+    TDataFileBase()
+        : Start(nullptr)
+        , Length(0)
+    {
+    }
+
+    void DoLoad(TFile& f, int loadMode, void* hdrPtr, size_t hdrSize);
+    void DoLoad(const char* fname, int loadMode); // just whole file
+    void Destroy();
+    void swap(TDataFileBase& with) {
+        MemData.swap(with.MemData);
+        FileData.swap(with.FileData);
+        DoSwap(Start, with.Start);
+        DoSwap(Length, with.Length);
+    }
+
+public:
+    void Precharge() const;
+};
+
+template <class TFileHeader>
+class TDataFile: public TDataFileBase {
+protected:
+    void Load(const char* fname, EDataLoadMode loadMode) {
+        Destroy();
+        TFile f(fname, RdOnly | Seq);
+        TFileHeader hdr;
+        f.Load(&hdr, sizeof(hdr));
+        Length = hdr.FileSize();
+        DoLoad(f, (int)loadMode, &hdr, sizeof(hdr));
+    }
+    const TFileHeader& Hdr() const {
+        return *(TFileHeader*)Start;
+    }
+};
+
+// Use: class TFoo: public TDataFileEx<Foo> {...};
+// Additional requrement: TFileHeader must have Validate(fname) function that throws exception.
+// Class TUser itself must have Init(fname) function
+// Adds Load() function to your class (TUser)
+template <class TUser, class TFileHeader>
+class TDataFileEx: public TDataFile<TFileHeader> {
+private:
+    using TBase = TDataFile<TFileHeader>;
+    TUser& User() const {
+        return *(TUser*)this;
+    }
+
+public:
+    TDataFileEx(const char* fname, EDataLoadMode loadMode = DLM_DEFAULT) {
+        if (fname)
+            Load(fname, loadMode);
+    }
+    void Load(const char* fname, EDataLoadMode loadMode = DLM_DEFAULT) {
+        TBase::Load(fname, loadMode);
+        TBase::Hdr().Validate(fname);
+        User().Init(fname);
+    }
+};