public static Result <bool, ErrorInfo> IsLastFrameCorrupt(Stream stream)
{
return
(Match(FileTraits.DetermineFileTraits(stream),
onOk: traits => {
Result <bool, ErrorInfo> isCorrupt;
var count = traits.CalculatedFrameCount;
if (count == 0)
{
// Not frames at all, let's not call that corrupt.
isCorrupt = Result <bool, ErrorInfo> .Ok(false);
WriteDebugConsole($"$$$ count=[{count}], not corrupt");
}
else if (count < 1.0)
{
isCorrupt = Result <bool, ErrorInfo> .Ok(true);
WriteDebugConsole($"$$$ count=[{count}], corrupt");
}
else
{
var fiLastFullFrame = (uint)(Floor(count)) - 1;
var hasPartialFrame = count != fiLastFullFrame + 1;
var offsetAdjust = hasPartialFrame ? 1u : 0u;
var frameOffset = CalculateFrameOffset(fiLastFullFrame + offsetAdjust, traits);
isCorrupt =
Match(ReadUInt32(frameOffset + ArisFrameHeaderOffsets.Version, stream),
onOk: version => {
var sizeOfLastFrame = traits.FileSize - frameOffset;
var expectedFrameSize = traits.FrameSize;
var corrupt =
traits.FileSignature != version ||
sizeOfLastFrame < expectedFrameSize;
WriteDebugConsole($"sizeOfLastFrame=[{sizeOfLastFrame}]");
WriteDebugConsole($"expectedFrameSize=[{expectedFrameSize}]");
WriteDebugConsole("traits.FileSignature != version=" + (traits.FileSignature != version));
WriteDebugConsole("sizeOfLastFrame < expectedFrameSize=" + (sizeOfLastFrame < expectedFrameSize));
WriteDebugConsole($"count=[{count}]; isCorrupt={corrupt}");
return Result <bool, ErrorInfo> .Ok(corrupt);
},
onError: errorInfo => {
WriteDebugConsole($"$count=[{count}]; couldn't read version, corrupt");
return Result <bool, ErrorInfo> .Ok(true);
});
}
return isCorrupt;
},
onError: errorInfo => Result <bool, ErrorInfo> .Error(
errorInfo.Append("Couldn't load traits to check for frame corruption"))));
}
public static void TruncateToNFrames(uint frameCount, Stream stream, string streamName)
{
MatchVoid(FileTraits.DetermineFileTraits(stream),
onOk: traits => {
var fi = Min(frameCount, (uint)Floor(traits.CalculatedFrameCount));
var frameOffset = CalculateFrameOffset(fi, traits);
stream.SetLength(frameOffset);
},
onError: msg => {
// Distinguish Serilog.Log from Math.Log
Serilog.Log.Information("Could not determine file traits for {streamName}: {msg}", streamName, msg);
});
}
public static Result <FileCheckResult, ErrorInfo> CheckFileForProblems(string path, Stream stream)
{
return(Match(FileTraits.DetermineFileTraits(stream),
onOk: traits =>
{
return Result <FileCheckResult, ErrorInfo> .Ok(new FileCheckResult(
path,
invalidHeaderValues: false,
isFileHeaderFrameCountCorrect:
traits.FileHeaderFrameCount == (int)Floor(traits.CalculatedFrameCount),
isLastFrameCorrupted: Match(IsLastFrameCorrupt(stream),
onOk: isCorrupt => isCorrupt,
onError: msg => false),
isLastFramePartial: traits.CalculatedFrameCount != Floor(traits.CalculatedFrameCount),
isFileEmpty: Floor(traits.CalculatedFrameCount) == 0,
calculatedFrameCount: traits.CalculatedFrameCount));
},
onError: errorInfo => Result <FileCheckResult, ErrorInfo> .Error(errorInfo)));
}
public static Result <uint, ErrorInfo> ReverseCountBadTrailingFrames(Stream stream)
{
return(Match(FileTraits.DetermineFileTraits(stream),
onOk: traits => {
var frameCount = (uint)Floor(traits.CalculatedFrameCount);
if (frameCount == 0)
{
return Result <uint, ErrorInfo> .Ok(0);
}
else
{
var badFrameCount = 0u;
while (frameCount > 0)
{
var fi = frameCount - 1;
var isBad = IsBad(fi);
if (isBad)
{
++badFrameCount;
--frameCount;
}
else
{
break;
}
}
return Result <uint, ErrorInfo> .Ok(badFrameCount);
bool IsBad(uint frameIndex)
{
var frameOffset = CalculateFrameOffset(frameIndex, traits);
return Match(ReadUInt32(frameOffset + ArisFrameHeaderOffsets.Version, stream),
onOk: version => traits.FileSignature != version,
onError: msg => true);
}
}
},
onError: errorInfo => Result <uint, ErrorInfo> .Error(
errorInfo.Append("Couldn't count trailing bad frames"))));
}
public static Result <FileCheckResult, ErrorInfo> FixTheFile(string path, ConfirmTruncationFn confirmTruncation)
{
using (var stream = File.Open(path, FileMode.Open, FileAccess.ReadWrite, FileShare.Read))
{
var problems = CheckFileForProblems(path, stream);
MatchVoid(FileTraits.DetermineFileTraits(stream),
onOk: traits => {
var calculated = (uint)(Floor(traits.CalculatedFrameCount));
MatchVoid(ReverseCountBadTrailingFrames(stream),
onOk: lengthOfTrailingBadFrames =>
{
var firstBad = lengthOfTrailingBadFrames;
var newFrameCount = calculated - lengthOfTrailingBadFrames;
var oldFrameCount = calculated;
if (confirmTruncation(newFrameCount, oldFrameCount) == ConsentResponse.PleaseFix)
{
TruncateToNFrames(newFrameCount, stream, Path.GetFileName(path));
SetMasterHeaderFrameCount(newFrameCount, stream);
Serilog.Log.Information("Truncated {filename} to {newFrameCount} frames",
Path.GetFileName(path), newFrameCount);
}
else
{
Serilog.Log.Information("Caller doesn't want to truncate after all.");
}
},
onError: msg =>
{
if (calculated != traits.FileHeaderFrameCount)
{
SetMasterHeaderFrameCount(calculated, stream);
}
});
},
onError: msg => { } /* nothing to be done */);
return(CheckFileForProblems(path, stream));
}
}
public static long CalculateFrameOffset(uint frameIndex, FileTraits traits) => traits.FileHeaderSize + ((long)frameIndex * traits.FrameSize);
