Share common code ZipArchive TryReadZip64EndOfCentralDirectory

Author: carlossanlop

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipArchive.Async.cs

@@ -246,7 +246,6 @@ private async Task ReadCentralDirectoryAsync(CancellationToken cancellationToken
         }
     }
 
-
     // This function reads all the EOCD stuff it needs to find the offset to the start of the central directory
     // This offset gets put in _centralDirectoryStart and the number of this disk gets put in _numberOfThisDisk
     // Also does some verification that this isn't a split/spanned archive
@@ -312,34 +311,10 @@ private async Task TryReadZip64EndOfCentralDirectoryAsync(ZipEndOfCentralDirecto
             {
                 // use locator to get to Zip64-EOCD
                 (bool zip64eocdLocatorProper, Zip64EndOfCentralDirectoryLocator locator) = await Zip64EndOfCentralDirectoryLocator.TryReadBlockAsync(_archiveStream, cancellationToken).ConfigureAwait(false);
-                Debug.Assert(zip64eocdLocatorProper); // we just found this using the signature finder, so it should be okay
-
-                if (locator.OffsetOfZip64EOCD > long.MaxValue)
-                    throw new InvalidDataException(SR.FieldTooBigOffsetToZip64EOCD);
-
-                long zip64EOCDOffset = (long)locator.OffsetOfZip64EOCD;
-
-                _archiveStream.Seek(zip64EOCDOffset, SeekOrigin.Begin);
-
+                TryReadZip64EndOfCentralDirectoryPostLocateZip64Block(zip64eocdLocatorProper, locator);
                 // Read Zip64 End of Central Directory Record
-
                 (bool result, Zip64EndOfCentralDirectoryRecord record) = await Zip64EndOfCentralDirectoryRecord.TryReadBlockAsync(_archiveStream, cancellationToken).ConfigureAwait(false);
-                if (!result)
-                    throw new InvalidDataException(SR.Zip64EOCDNotWhereExpected);
-
-                _numberOfThisDisk = record.NumberOfThisDisk;
-
-                if (record.NumberOfEntriesTotal > long.MaxValue)
-                    throw new InvalidDataException(SR.FieldTooBigNumEntries);
-
-                if (record.OffsetOfCentralDirectory > long.MaxValue)
-                    throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
-
-                if (record.NumberOfEntriesTotal != record.NumberOfEntriesOnThisDisk)
-                    throw new InvalidDataException(SR.SplitSpanned);
-
-                _expectedNumberOfEntries = (long)record.NumberOfEntriesTotal;
-                _centralDirectoryStart = (long)record.OffsetOfCentralDirectory;
+                TryReadZip64EndOfCentralDirectoryPostReadZip64Block(result, record);
             }
         }
     }

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipArchive.cs

@@ -677,6 +677,38 @@ private void ReadEndOfCentralDirectory()
             }
         }
 
+        private void TryReadZip64EndOfCentralDirectoryPostReadZip64Block(bool result, Zip64EndOfCentralDirectoryRecord record)
+        {
+            if (!result)
+                throw new InvalidDataException(SR.Zip64EOCDNotWhereExpected);
+
+            _numberOfThisDisk = record.NumberOfThisDisk;
+
+            if (record.NumberOfEntriesTotal > long.MaxValue)
+                throw new InvalidDataException(SR.FieldTooBigNumEntries);
+
+            if (record.OffsetOfCentralDirectory > long.MaxValue)
+                throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
+
+            if (record.NumberOfEntriesTotal != record.NumberOfEntriesOnThisDisk)
+                throw new InvalidDataException(SR.SplitSpanned);
+
+            _expectedNumberOfEntries = (long)record.NumberOfEntriesTotal;
+            _centralDirectoryStart = (long)record.OffsetOfCentralDirectory;
+        }
+
+        private void TryReadZip64EndOfCentralDirectoryPostLocateZip64Block(bool zip64eocdLocatorProper, Zip64EndOfCentralDirectoryLocator locator)
+        {
+            Debug.Assert(zip64eocdLocatorProper); // we just found this using the signature finder, so it should be okay
+
+            if (locator.OffsetOfZip64EOCD > long.MaxValue)
+                throw new InvalidDataException(SR.FieldTooBigOffsetToZip64EOCD);
+
+            long zip64EOCDOffset = (long)locator.OffsetOfZip64EOCD;
+
+            _archiveStream.Seek(zip64EOCDOffset, SeekOrigin.Begin);
+        }
+
         // Tries to find the Zip64 End of Central Directory Locator, then the Zip64 End of Central Directory, assuming the
         // End of Central Directory block has already been found, as well as the location in the stream where the EOCD starts.
         private void TryReadZip64EndOfCentralDirectory(ZipEndOfCentralDirectoryBlock eocd, long eocdStart)
@@ -701,34 +733,10 @@ private void TryReadZip64EndOfCentralDirectory(ZipEndOfCentralDirectoryBlock eoc
                 {
                     // use locator to get to Zip64-EOCD
                     bool zip64eocdLocatorProper = Zip64EndOfCentralDirectoryLocator.TryReadBlock(_archiveStream, out Zip64EndOfCentralDirectoryLocator locator);
-                    Debug.Assert(zip64eocdLocatorProper); // we just found this using the signature finder, so it should be okay
-
-                    if (locator.OffsetOfZip64EOCD > long.MaxValue)
-                        throw new InvalidDataException(SR.FieldTooBigOffsetToZip64EOCD);
-
-                    long zip64EOCDOffset = (long)locator.OffsetOfZip64EOCD;
-
-                    _archiveStream.Seek(zip64EOCDOffset, SeekOrigin.Begin);
-
+                    TryReadZip64EndOfCentralDirectoryPostLocateZip64Block(zip64eocdLocatorProper, locator);
                     // Read Zip64 End of Central Directory Record
-
-                    Zip64EndOfCentralDirectoryRecord record;
-                    if (!Zip64EndOfCentralDirectoryRecord.TryReadBlock(_archiveStream, out record))
-                        throw new InvalidDataException(SR.Zip64EOCDNotWhereExpected);
-
-                    _numberOfThisDisk = record.NumberOfThisDisk;
-
-                    if (record.NumberOfEntriesTotal > long.MaxValue)
-                        throw new InvalidDataException(SR.FieldTooBigNumEntries);
-
-                    if (record.OffsetOfCentralDirectory > long.MaxValue)
-                        throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
-
-                    if (record.NumberOfEntriesTotal != record.NumberOfEntriesOnThisDisk)
-                        throw new InvalidDataException(SR.SplitSpanned);
-
-                    _expectedNumberOfEntries = (long)record.NumberOfEntriesTotal;
-                    _centralDirectoryStart = (long)record.OffsetOfCentralDirectory;
+                    bool result = Zip64EndOfCentralDirectoryRecord.TryReadBlock(_archiveStream, out Zip64EndOfCentralDirectoryRecord record);
+                    TryReadZip64EndOfCentralDirectoryPostReadZip64Block(result, record);
                 }
             }
         }