From bcfb40dde37a69139ef7ea2748ccfa642d3bee53 Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Thu, 17 Feb 2011 18:02:24 +0000
Subject: Wow, MyriadFs is actually getting workable.  You can create files,
 read, write, etc.  Next up is creating directories, and other special file
 types.

---
 src/myriadfs.h | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 94 insertions(+), 6 deletions(-)

(limited to 'src/myriadfs.h')

diff --git a/src/myriadfs.h b/src/myriadfs.h
index 856137c..808444b 100644
--- a/src/myriadfs.h
+++ b/src/myriadfs.h
@@ -19,13 +19,10 @@ namespace Bu
 	/**
 	 * A POSIX compliant, node based filesystem built on top of Myriad.
 	 *
-	 * Think about putting this all in one stream, on block boundaries.
-	 *
 	 * A header is placed into stream 1.
 	 * Header format:
 	 *   int32_t iMagicHeader  (A7188B39)
 	 *   int8_t iVersion (1)
-	 *   int32_t iNodeSize
 	 *   int32_t iNumNodes
 	 *   NodeLookup[iNumNodes] nNode
 	 *
@@ -33,10 +30,10 @@ namespace Bu
 	 *   int32_t iInode
 	 *   int32_t iPosition
 	 *
-	 * The node headers or inode structures have a base size of 22 bytes.
+	 * The node headers or inode structures have a base size of 46 bytes.
 	 * Everything else in the block is used for the name.  I.e. if you have
 	 * a blocksize of 512 bytes then you wind up with a max name size of
-	 * 512-22=490 characters, or a blocksize of 256 gives you 234 chraacters
+	 * 512-46=466 characters, or a blocksize of 256 gives you 210 chraacters
 	 * as a max.  The node headers are all stored in stream 2.
 	 * Basic node header format:
 	 *   int32_t iUser
@@ -50,6 +47,27 @@ namespace Bu
 	 *   int64_t iCTime
 	 *   int16_t iNameSize
 	 *   char[iNameSize] sName
+	 *
+	 * Some types get special formats for their assosiated data stream, or
+	 * other special considerations, here's a list:
+	 *
+	 * - typeFifo: No stream, iStreamIndex unused (probably)
+	 * - typeChrDev: No stream, iStreamIndex is device hi/lo
+	 * - typeDir: The stream contains a directory contents listing, described
+	 *            below
+	 * - typeBlkDev: No stream, iStreamIndex is device hi/lo
+	 * - typeRegFile: The stream is the file data
+	 * - typeSymLink: The stream is the destination of the symlink
+	 * - typeSocket: No steram, iStreamIndex unused (probably)
+	 *
+	 * Directory streams have this simple listing format.  They contain a list
+	 * of all child elements, with no particular order at the moment.  The . and
+	 * .. entries are not listed, they are implicit:
+	 *   int32_t iNumNodes
+	 *   NodeTable[iNumNodes] nChildren
+	 *
+	 * NodeTable:
+	 *   int32_t iInode
 	 */
 	class MyriadFs
 	{
@@ -79,11 +97,81 @@ namespace Bu
 			typeSymLink	= 0120000,
 			typeSocket	= 0140000,
 			typeMask	= 0170000
-		}
+		};
+
+		enum
+		{
+			Read		= 0x01,	///< Open file for reading
+			Write		= 0x02, ///< Open file for writing
+			Create		= 0x04, ///< Create file if it doesn't exist
+			Truncate	= 0x08, ///< Truncate file if it does exist
+			Append		= 0x10, ///< Always append on every write
+			NonBlock	= 0x20, ///< Open file in non-blocking mode
+			Exclusive	= 0x44, ///< Create file, if it exists then fail
+
+			// Helpful mixes
+			ReadWrite	= 0x03, ///< Open for reading and writing
+			WriteNew	= 0x0E	///< Create a file (or truncate) for writing.
+								/// Same as Write|Create|Truncate
+		};
+		
+		class Stat
+		{
+		public:
+			int32_t iNode;
+			int32_t iUser;
+			int32_t iGroup;
+			uint16_t uPerms;
+			int16_t iLinks;
+			int64_t iATime;
+			int64_t iMTime;
+			int64_t iCTime;
+			int32_t iSize;
+			Bu::String sName;
+		};
+		typedef Bu::List<Stat> Dir;
+
+		void stat( const Bu::String &sPath, Stat &rBuf );
+		MyriadStream open( const Bu::String &sPath, int iMode );
+//		void create( const Bu::String &sPath, uint16_t iPerms );
+
+
+	private:
+		class RawStat
+		{
+		public:
+			int32_t iUser;
+			int32_t iGroup;
+			uint16_t uPerms;
+			int16_t iLinks;
+			int32_t iStreamIndex;
+			int32_t iParentNode;
+			int64_t iATime;
+			int64_t iMTime;
+			int64_t iCTime;
+			int16_t iNameSize;
+		};
+		typedef Bu::Hash<int32_t, int32_t> NodeIndex;
+
+	private:
+		int32_t lookupInode( const Bu::String &sPath, int32_t &iParent );
+		int32_t lookupInode( Bu::String::const_iterator iStart,
+				int32_t iNode, int32_t &iParent );
+		Dir readDir( int32_t iNode );
+		MyriadStream openByInode( int32_t iNode );
+		int32_t create( int32_t iParent, const Bu::String &sName,
+				uint16_t uPerms );
+		int32_t allocInode( const Bu::String &sName, int32_t iParent,
+				uint16_t uPerms );
+		void stat( int32_t iNode, Stat &rBuf, MyriadStream &rIs );
+		void writeHeader();
 
 	private:
 		Bu::Stream &rStore;
 		Bu::Myriad mStore;
+		NodeIndex hNodeIndex;
+		int32_t iUser;
+		int32_t iGroup;
 	};
 };
 
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