Start refactoring to reduce executable type knowledge.

courgette/courgette.h

Index: courgette/courgette.h
diff --git a/courgette/courgette.h b/courgette/courgette.h
index 521053e06550b5b5d2bcbd5bd40e9c90d698e2f8..f847f5056944becf750319f15610c18e1c942514 100644
--- a/courgette/courgette.h
+++ b/courgette/courgette.h
@@ -50,6 +50,13 @@ enum Status {
   C_ADJUSTMENT_FAILED = 27,       //
 };
 
+// What type of executable is something
+// Generally corresponds to CourgettePatchFile::TransformationMethodId
+enum ExecutableType {
+  UNKNOWN,
+  WIN32_X86
+};
+
 class SinkStream;
 class SinkStreamSet;
 class SourceStream;
@@ -84,8 +91,14 @@ Status GenerateEnsemblePatch(SourceStream* old, SourceStream* target,
 // storing the pointer to the AssemblyProgram in |*output|.
 // Returns C_OK if successful, otherwise returns an error status and sets
 // |*output| to NULL.
-Status ParseWin32X86PE(const void* buffer, size_t length,
-                       AssemblyProgram** output);
+ExecutableType DetectExecutableType(const void* buffer, size_t length);
+
+// Attempts to detect the type of executable, and parse it with the
+// appropriate tools, storing the pointer to the AssemblyProgram in |*output|.
+// Returns C_OK if successful, otherwise returns an error status and sets
+// |*output| to NULL.
+Status ParseDetectedExecutable(const void* buffer, size_t length,
+                               AssemblyProgram** output);
 
 // Converts |program| into encoded form, returning it as |*output|.
 // Returns C_OK if succeeded, otherwise returns an error status and