KPath: Use an object_cache for the path buffers in the normal case.

This was (following the packagefs changes) the number-one (by call
count) consumer of malloc() during the boot -- 52866 calls, and 100%
of them either 1024 or 1025 bytes!

Virtually all of these are ephemeral (indeed, the object_cache
stats after a boot with this patch shows there is only a single slab
of 64 buffers allocated, and most of them unused), so this is
probably a significant performance boost.

Change-Id: I659f5707510cbfeafa735d35eea7b92732ead666

KPath: Added LAZY_ALLOC flag.

* This allows KPath to not allocate a buffer when initialized
without path.
* Added test cases for this.
* Added test for LockBuffer().
* Enhanced tests to allow building them in debug mode.
* Moved calling vfs_normalize_path() into own private method.
* Improved error codes; B_NO_MEMORY is now only returned if the
allocation actually failed.
* If used with LAZY_ALLOC, Path() and LockBuffer() are now allowed
to return a NULL path.

KPath: Replaced booleans with flags field.

* No functional change intended; I chose the flags in a way that it
should still work even if I missed a reference.

Minor style cleanup.

* vfs_normalize_path() and _user_normalize_path() use a common helper
function (normalize_path()), now. There was some code duplication
before.
* Added "bool traverseLink" parameter to vfs_normalize_path(). When
true and the leaf component is a symlink, it will be resolved.
* KPath:
- Added similar leaf link traversal parameter to SetTo() and
SetPath().
- Added Normalize().
- Added DetachBuffer(), which returns the object's current buffer and
unsets itself.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27751 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Added Adopt() method that steals the other path's buffer.
* Fixed operator=(): the second argument of SetTo() is a boolean (normalize),
not the length of the buffer.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25382 a95241bf-73f2-0310-859d-f6bbb57e9c96

Added RemoveLeaf() leaf method. Very handy for recursive directory
iteration code using a single KPath object.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@21606 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Reduced the stack usage of most of the I/O paths - there were several places
that put one or more full paths on the stack before, which could cause some
problems under certain conditions.
* Cleaned up KPath, ie. use size_t instead of int32 where appropriate, added
license.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16585 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixed a warning in GCC 3.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9794 a95241bf-73f2-0310-859d-f6bbb57e9c96

Added support for path normalization.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9625 a95241bf-73f2-0310-859d-f6bbb57e9c96

Extended Append() to also allow adding parts of path components. Added leaf component manipulation. Now always chop trailing slashes off the path.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9560 a95241bf-73f2-0310-859d-f6bbb57e9c96

Added class KPath. Convenient wrapper for a fixed-sized path buffer.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9541 a95241bf-73f2-0310-859d-f6bbb57e9c96

* vfs_normalize_path() and _user_normalize_path() use a common helper
function (normalize_path()), now. There was some code duplication
before.
* Added "bool traverseLink" parameter to vfs_normalize_path(). When
true and the leaf component is a symlink, it will be resolved.
* KPath:
- Added similar leaf link traversal parameter to SetTo() and
SetPath().
- Added Normalize().
- Added DetachBuffer(), which returns the object's current buffer and
unsets itself.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27751 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Added Adopt() method that steals the other path's buffer.
* Fixed operator=(): the second argument of SetTo() is a boolean (normalize),
not the length of the buffer.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25382 a95241bf-73f2-0310-859d-f6bbb57e9c96

Added RemoveLeaf() leaf method. Very handy for recursive directory
iteration code using a single KPath object.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@21606 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Reduced the stack usage of most of the I/O paths - there were several places
that put one or more full paths on the stack before, which could cause some
problems under certain conditions.
* Cleaned up KPath, ie. use size_t instead of int32 where appropriate, added
license.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16585 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixed a warning in GCC 3.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9794 a95241bf-73f2-0310-859d-f6bbb57e9c96

Added support for path normalization.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9625 a95241bf-73f2-0310-859d-f6bbb57e9c96

Extended Append() to also allow adding parts of path components. Added leaf component manipulation. Now always chop trailing slashes off the path.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9560 a95241bf-73f2-0310-859d-f6bbb57e9c96

Added class KPath. Convenient wrapper for a fixed-sized path buffer.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9541 a95241bf-73f2-0310-859d-f6bbb57e9c96