Made invariant of class 'Scanner' robust by changing the design (replaced public field by private field + getter/setter).

1 files changed, 15 insertions, 4 deletions

diff --git a/Source/Core/Scanner.cs b/Source/Core/Scanner.cs
index 5b5c0306..c6b15cc5 100644
--- a/Source/Core/Scanner.cs
+++ b/Source/Core/Scanner.cs
@@ -217,7 +217,7 @@ public class Scanner {
 

 	[ContractInvariantMethod]

 	void objectInvariant(){

-		Contract.Invariant(buffer!=null);

+		Contract.Invariant(this._buffer != null);

 		Contract.Invariant(t != null);

 		Contract.Invariant(start != null);

 		Contract.Invariant(tokens != null);

@@ -227,7 +227,18 @@ public class Scanner {
 		Contract.Invariant(errorHandler != null);

 	}

 

-	public Buffer/*!*/ buffer; // scanner buffer

+	private Buffer/*!*/ _buffer; // scanner buffer

+

+  public Buffer/*!*/ buffer {

+    get {

+      Contract.Ensures(Contract.Result<Buffer>() != null);

+      return this._buffer;

+    }

+    set {

+      Contract.Requires(value != null);

+      this._buffer = value;

+    }

+  }

 

 	Token/*!*/ t;          // current token

 	int ch;           // current input character

@@ -304,7 +315,7 @@ public class Scanner {
 		t = new Token(); // dummy because t is a non-null field

 		try {

 			Stream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);

-			buffer = new Buffer(stream, false);

+			this._buffer = new Buffer(stream, false);

 			Filename = useBaseName? GetBaseName(fileName): fileName;

 			Init();

 		} catch (IOException) {

@@ -319,7 +330,7 @@ public class Scanner {
 	  Contract.Requires(fileName != null);

 		pt = tokens = new Token();  // first token is a dummy

 		t = new Token(); // dummy because t is a non-null field

-		buffer = new Buffer(s, true);

+    this._buffer = new Buffer(s, true);

 		this.errorHandler = errorHandler;

 		this.Filename = useBaseName? GetBaseName(fileName) : fileName;

 		Init();