Imported Upstream version 5.2.0.175

Former-commit-id: bb0468d0f257ff100aa895eb5fe583fb5dfbf900

external/linker/cecil/symbols/pdb/Mono.Cecil.Pdb/PdbHelper.cs

@@ -22,7 +22,7 @@ namespace Mono.Cecil.Pdb {
 			Mixin.CheckModule (module);
 			Mixin.CheckFileName (fileName);
 
-			return new PdbReader (Disposable.Owned (File.OpenRead (Mixin.GetPdbFileName (fileName)) as Stream));
+			return new NativePdbReader (Disposable.Owned (File.OpenRead (Mixin.GetPdbFileName (fileName)) as Stream));
 		}
 
 		public ISymbolReader GetSymbolReader (ModuleDefinition module, Stream symbolStream)
@@ -30,7 +30,7 @@ namespace Mono.Cecil.Pdb {
 			Mixin.CheckModule (module);
 			Mixin.CheckStream (symbolStream);
 
-			return new PdbReader (Disposable.NotOwned (symbolStream));
+			return new NativePdbReader (Disposable.NotOwned (symbolStream));
 		}
 	}
 
@@ -41,7 +41,14 @@ namespace Mono.Cecil.Pdb {
 			Mixin.CheckModule (module);
 			Mixin.CheckFileName (fileName);
 
-			return IsPortablePdb (Mixin.GetPdbFileName (fileName))
+			if (module.HasDebugHeader) {
+				var header = module.GetDebugHeader ();
+				var entry = header.GetEmbeddedPortablePdbEntry ();
+				if (entry != null)
+					return new EmbeddedPortablePdbReaderProvider ().GetSymbolReader (module, fileName);
+			}
+
+			return Mixin.IsPortablePdb (Mixin.GetPdbFileName (fileName))
 				? new PortablePdbReaderProvider ().GetSymbolReader (module, fileName)
 				: new NativePdbReaderProvider ().GetSymbolReader (module, fileName);
 		}
@@ -52,29 +59,10 @@ namespace Mono.Cecil.Pdb {
 			Mixin.CheckStream (symbolStream);
 			Mixin.CheckReadSeek (symbolStream);
 
-			return IsPortablePdb (symbolStream)
+			return Mixin.IsPortablePdb (symbolStream)
 				? new PortablePdbReaderProvider ().GetSymbolReader (module, symbolStream)
 				: new NativePdbReaderProvider ().GetSymbolReader (module, symbolStream);
 		}
-
-		static bool IsPortablePdb (string fileName)
-		{
-			using (var file = new FileStream (fileName, FileMode.Open, FileAccess.Read, FileShare.None))
-				return IsPortablePdb (file);
-		}
-
-		static bool IsPortablePdb (Stream stream)
-		{
-			const uint ppdb_signature = 0x424a5342;
-
-			var position = stream.Position;
-			try {
-				var reader = new BinaryReader (stream);
-				return reader.ReadUInt32 () == ppdb_signature;
-			} finally {
-				stream.Position = position;
-			}
-		}
 	}
 
 #if !READ_ONLY
@@ -86,7 +74,7 @@ namespace Mono.Cecil.Pdb {
 			Mixin.CheckModule (module);
 			Mixin.CheckFileName (fileName);
 
-			return new PdbWriter (module, CreateWriter (module, Mixin.GetPdbFileName (fileName)));
+			return new NativePdbWriter (module, CreateWriter (module, Mixin.GetPdbFileName (fileName)));
 		}
 
 		static SymWriter CreateWriter (ModuleDefinition module, string pdb)