Reid Spencer a229c5cce7 Final Changes For PR495:
This chagne just renames some sys::Path methods to ensure they are not
misused. The Path documentation now divides methods into two dimensions:
Path/Disk and accessor/mutator. Path accessors and mutators only operate
on the Path object itself without making any disk accesses. Disk accessors
and mutators will also access or modify the file system. Because of the
potentially destructive nature of disk mutators, it was decided that all
such methods should end in the work "Disk" to ensure the user recognizes
that the change will occur on the file system. This patch makes that
change. The method name changes are:

makeReadable        -> makeReadableOnDisk
makeWriteable       -> makeWriteableOnDisk
makeExecutable      -> makeExecutableOnDisk
setStatusInfo       -> setStatusInfoOnDisk
createDirectory     -> createDirectoryOnDisk
createFile          -> createFileOnDisk
createTemporaryFile -> createTemporaryFileOnDisk
destroy             -> eraseFromDisk
rename              -> renamePathOnDisk

These changes pass the Linux Deja Gnu tests.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22354 91177308-0d34-0410-b5e6-96231b3b80d8
2005-07-08 03:08:58 +00:00
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Design Of lib/System
====================

The software in this directory is designed to completely shield LLVM from any
and all operating system specific functionality. It is not intended to be a
complete operating system wrapper (such as ACE), but only to provide the
functionality necessary to support LLVM.

The software located here, of necessity, has very specific and stringent design
rules. Violation of these rules means that cracks in the shield could form and
the primary goal of the library is defeated. By consistently using this library,
LLVM becomes more easily ported to new platforms since the only thing requiring 
porting is this library.

Complete documentation for the library can be found in the file:
  llvm/docs/SystemLibrary.html 
or at this URL:
  http://llvm.cs.uiuc.edu/docs/SystemLibrary.html

While we recommend that you read the more detailed documentation, for the 
impatient, here's a high level summary of the library's requirements.

 1. No system header files are to be exposed through the interface.
 2. Std C++ and Std C header files are okay to be exposed through the interface.
 3. No exposed system-specific functions.
 4. No exposed system-specific data.
 5. Data in lib/System classes must use only simple C++ intrinsic types.
 6. Errors are handled by throwing std::string *only*.
 7. Library must not throw any exceptions except std::string.
 8. Interface functions must not have throw() specifications.
 9. No duplicate function impementations are permitted within an operating
    system class.

To accomplish these requirements, the library has numerous design criteria that 
must be satisfied. Here's a high level summary of the library's design criteria:

 1. No unused functionality (only what LLVM needs)
 2. High-Level Interfaces
 3. Use Opaque Classes
 4. Common Implementations</a></li>
 5. Multiple Implementations</a></li>
 6. Minimize Memory Allocation</a></li>
 7. No Virtual Methods