* Added new (currently private) API class BMimeSnifferAddon,

representing the interface for, well, MIME sniffer add-ons.
* Implemented the respective add-on manager and make use of it in
  the MIME database code. Unfortunately the MIME DB code completely
  lives in libbe.so and hence I had to put my code there too.
  IMHO we should (one day) remove the direct (read-only) MIME DB
  access from libbe and move everything into the registrar.
  Currently the add-on manager supports built-in add-ons only; it
  doesn't really load anything from disk ATM.
* Added a built-in text sniffer add-on to the registrar. It's based
  upon the BSD file tool code.

This closes bug #250 (plain text files are identified as such, now).



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17784 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/add-ons/registrar/MimeSnifferAddon.h

@@ -0,0 +1,32 @@
+/* MIME Sniffer Add-On Protocol
+ *
+ * Copyright 2006, Haiku Inc. All Rights Reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef _MIME_SNIFFER_ADDON_H
+#define _MIME_SNIFFER_ADDON_H
+
+#include <SupportDefs.h>
+
+class BFile;
+class BMimeType;
+
+// **********************************
+// *** WARNING: EXPERIMENTAL API! ***
+// **********************************
+
+class BMimeSnifferAddon {
+public:
+								BMimeSnifferAddon();
+	virtual						~BMimeSnifferAddon();
+
+	virtual	size_t				MinimalBufferSize();
+
+	virtual	float				GuessMimeType(const char* fileName,
+									BMimeType* type);
+	virtual	float				GuessMimeType(BFile* file,
+									const void* buffer, int32 length,
+									BMimeType* type);
+};
+
+#endif	// _MIME_SNIFFER_ADDON_H

headers/private/storage/mime/MimeSnifferAddonManager.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2006, Ingo Weinhold <[email protected]>.
+ * All rights reserved. Distributed under the terms of the MIT License.
+ */
+#ifndef MIME_SNIFFER_ADDON_MANAGER_H
+#define MIME_SNIFFER_ADDON_MANAGER_H
+
+#include <List.h>
+#include <Locker.h>
+
+class BFile;
+class BMimeSnifferAddon;
+class BMimeType;
+
+namespace BPrivate {
+namespace Storage {
+namespace Mime {
+
+
+class MimeSnifferAddonManager {
+private:
+								MimeSnifferAddonManager();
+								~MimeSnifferAddonManager();
+
+public:
+	static	MimeSnifferAddonManager* Default();
+	static	status_t			CreateDefault();
+	static	void				DeleteDefault();
+
+			status_t			AddMimeSnifferAddon(BMimeSnifferAddon* addon);
+
+			size_t				MinimalBufferSize();
+
+			float				GuessMimeType(const char* fileName,
+									BMimeType* type);
+			float				GuessMimeType(BFile* file,
+									const void* buffer, int32 length,
+									BMimeType* type);
+								
+private:
+			struct AddonReference;
+
+			status_t			_GetAddons(AddonReference**& references,
+									int32& count);
+			void				_PutAddons(AddonReference** references,
+									int32 count);
+
+			static MimeSnifferAddonManager*	sManager;
+
+			BLocker				fLock;
+			BList				fAddons;
+			size_t				fMinimalBufferSize;
+};
+
+}	// namespace Mime
+}	// namespace Storage
+}	// namespace BPrivate
+
+using BPrivate::Storage::Mime::MimeSnifferAddonManager;
+
+#endif	// MIME_SNIFFER_ADDON_MANAGER_H
+

headers/private/storage/mime/SnifferRules.h

@@ -50,7 +50,8 @@ public:
 	};		
 private:
 	status_t BuildRuleList();
-	status_t GuessMimeType(BPositionIO *data, BString *type);
+	status_t GuessMimeType(BFile* file, const void *buffer, int32 length,
+		BString *type);
 	ssize_t MaxBytesNeeded();
 	status_t ProcessType(const char *type, ssize_t *bytesNeeded);