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//////////////////////////////////////////////////////////////////////
rvs 0.6.1
retroactive versioning system
a versioning system that allows you to check
in commit 2 before commit 1
//////////////////////////////////////////////////////////////////////
hacking
There are two main parts to rvs, the wrapper, and the core. The
wrapper is a small executable, located in the PATH, and is the one
called when you type `rvs'. The core is a set of many small
executables that do all the real work.
build system
The build system rvs uses is rather simple.
`./configure' does two things:
* create a preprocessor (`tmp/var.sed')
* run `Makefile.orig' through the preprocessor to generate a
propper `Makefile'
Then, the Makefile runs each file in `source/' through the
preprocessor, and writes the resulting files to `out/'.
preprocessor
The preprocessor contains all configuration variables. When it
processes a file every instance of `$$VAR_NAME$$' is replaced by
that variable's value. Note that this replacement only happens for
defined variables.
configuration Variables
Again the configuration variables and their default values are:
VER '0.6.1'
SHELL '/usr/bin/env bash'
prefix "$HOME"
bindir 'bin'
libdir '/etc/rvs/'
The wrapper is installed at `$$prefix$$/$$bindir$$/rvs'
The core is installed at `$$libdir$$/'
The source for the wrapper is in `source/rvs'
The source for the core is in `source/rvs-core/'
$$SHELL$$ is the shell all shell scripts that are part of rvs are
run in. As of rvs 0.6.1 all executables are shell scripts.
Most of these can easily be changed _after_ compilation also:
VER line 4 of the wrapper
SHELL line 1 each shell script
prefix simply move the wrapper
bindir simply move the wrapper
libdir move the core, then update the line `RVSDIR=...' in
the wrapper
I have designed this system to be extremely modular. As you may
have figured out, each bit on functionality is in it's own
executable, and the file you call when you type `rvs' is just a
wrapper for them.
----------------------------------------------------------------------
----- The rest is copy/pasted, and still needs to be copy-edited.-----
----------------------------------------------------------------------
commit actually does take a parameter. It can commit any file or
directory. It works as it does because if no file is given, it
defaults to ./. If it is given a directory (as it is by
default), it loops through each file in the directory and
commits them (by calling itself). In order to actually commit a
file or directory it calls rvs commit.type where type is the
standard unix file-type code:
block (buffered) special b
character (unbuffered) special c
directory d
named pipe (FIFO) p
regular file f
symbolic link l
socket s
door (Solaris only) D
As you probably noticed, only directories and regular files have
been implemented in this release. get works in much the same
way. If you implement any other file types, save the commit and
get functions accordingly, and uncomment the line in
source/rvs-corecommit. Any commit function takes a filename as
an argument and outputs the according commit id to stdout. Any
get function takes the commit id as an argument and uses stdout
only if verbose, or to report errors. So the modules communicate
via pipes, which is generally considered bad-design, and
libraries should be used. I deliberatly broke this because this
way:
1. incompatible licences can be used for different modules
2. modules can be added/removed on the fly
3. one can use any lanugage to write new modules, without
having to worry about bindings
known bugs
* borks on files with the newline character. The smart thing
to do would be to escape all speacial characters.
Files to be changed:
* source/rvs-core/commit
* source/rvs-core/commit.d
* source/rvs-core/get.d
I have set up bazaar repository at Launchpad:
https://launchpad.net/rvs
Only until rvs becomes self-hosting.
If anyone needs any help, let me know.
~ Luke Shumaker <LukeShu@sbcglobal.net>
Happy Hacking!
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