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2.3 How data is stored in the working directory
While we are discussing CVS internals which may
become visible from time to time, we might as well talk
about what CVS puts in the `CVS' directories
in the working directories. As with the repository,
CVS handles this information and one can usually
access it via CVS commands. But in some cases it
may be useful to look at it, and other programs, such
as the jCVS graphical user interface or the
VC package for emacs, may need to look at it.
Such programs should follow the recommendations in this
section if they hope to be able to work with other
programs which use those files, including future
versions of the programs just mentioned and the
command-line CVS client.
The `CVS' directory contains several files.
Programs which are reading this directory should
silently ignore files which are in the directory but
which are not documented here, to allow for future
expansion.
The files are stored according to the text file
convention for the system in question. This means that
working directories are not portable between systems
with differing conventions for storing text files.
This is intentional, on the theory that the files being
managed by CVS probably will not be portable between
such systems either.
- `Root'
This file contains the current CVS root, as
described in Telling CVS where your repository is.
- `Repository'
This file contains the directory within the repository
which the current directory corresponds with. It can
be either an absolute pathname or a relative pathname;
CVS has had the ability to read either format
since at least version 1.3 or so. The relative
pathname is relative to the root, and is the more
sensible approach, but the absolute pathname is quite
common and implementations should accept either. For
example, after the command
| | cvs -d :local:/usr/local/cvsroot checkout yoyodyne/tc
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`Root' will contain
| | :local:/usr/local/cvsroot
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and `Repository' will contain either
| | /usr/local/cvsroot/yoyodyne/tc
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or
If the particular working directory does not correspond
to a directory in the repository, then `Repository'
should contain `CVSROOT/Emptydir'.
- `Entries'
This file lists the files and directories in the
working directory.
The first character of each line indicates what sort of
line it is. If the character is unrecognized, programs
reading the file should silently skip that line, to
allow for future expansion.
If the first character is `/', then the format is:
| | /name/revision/timestamp[+conflict]/options/tagdate
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where `[' and `]' are not part of the entry,
but instead indicate that the `+' and conflict
marker are optional. name is the name of the
file within the directory. revision is the
revision that the file in the working derives from, or
`0' for an added file, or `-' followed by a
revision for a removed file. timestamp is the
timestamp of the file at the time that CVS created
it; if the timestamp differs with the actual
modification time of the file it means the file has
been modified. It is stored in
the format used by the ISO C asctime() function (for
example, `Sun Apr 7 01:29:26 1996'). One may
write a string which is not in that format, for
example, `Result of merge', to indicate that the
file should always be considered to be modified. This
is not a special case; to see whether a file is
modified a program should take the timestamp of the file
and simply do a string compare with timestamp.
If there was a conflict, conflict can be set to
the modification time of the file after the file has been
written with conflict markers (see section Conflicts example).
Thus if conflict is subsequently the same as the actual
modification time of the file it means that the user
has obviously not resolved the conflict. options
contains sticky options (for example `-kb' for a
binary file). tagdate contains `T' followed
by a tag name, or `D' for a date, followed by a
sticky tag or date. Note that if timestamp
contains a pair of timestamps separated by a space,
rather than a single timestamp, you are dealing with a
version of CVS earlier than CVS 1.5 (not
documented here).
The timezone on the timestamp in CVS/Entries (local or
universal) should be the same as the operating system
stores for the timestamp of the file itself. For
example, on Unix the file's timestamp is in universal
time (UT), so the timestamp in CVS/Entries should be
too. On VMS, the file's timestamp is in local
time, so CVS on VMS should use local time.
This rule is so that files do not appear to be modified
merely because the timezone changed (for example, to or
from summer time).
If the first character of a line in `Entries' is
`D', then it indicates a subdirectory. `D'
on a line all by itself indicates that the program
which wrote the `Entries' file does record
subdirectories (therefore, if there is such a line and
no other lines beginning with `D', one knows there
are no subdirectories). Otherwise, the line looks
like:
| | D/name/filler1/filler2/filler3/filler4
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where name is the name of the subdirectory, and
all the filler fields should be silently ignored,
for future expansion. Programs which modify
Entries files should preserve these fields.
The lines in the `Entries' file can be in any order.
- `Entries.Log'
This file does not record any information beyond that
in `Entries', but it does provide a way to update
the information without having to rewrite the entire
`Entries' file, including the ability to preserve
the information even if the program writing
`Entries' and `Entries.Log' abruptly aborts.
Programs which are reading the `Entries' file
should also check for `Entries.Log'. If the latter
exists, they should read `Entries' and then apply
the changes mentioned in `Entries.Log'. After
applying the changes, the recommended practice is to
rewrite `Entries' and then delete `Entries.Log'.
The format of a line in `Entries.Log' is a single
character command followed by a space followed by a
line in the format specified for a line in
`Entries'. The single character command is
`A' to indicate that the entry is being added,
`R' to indicate that the entry is being removed,
or any other character to indicate that the entire line
in `Entries.Log' should be silently ignored (for
future expansion). If the second character of the line
in `Entries.Log' is not a space, then it was
written by an older version of CVS (not documented
here).
Programs which are writing rather than reading can
safely ignore `Entries.Log' if they so choose.
- `Entries.Backup'
This is a temporary file. Recommended usage is to
write a new entries file to `Entries.Backup', and
then to rename it (atomically, where possible) to `Entries'.
- `Entries.Static'
The only relevant thing about this file is whether it
exists or not. If it exists, then it means that only
part of a directory was gotten and CVS will
not create additional files in that directory. To
clear it, use the update command with the
`-d' option, which will get the additional files
and remove `Entries.Static'.
- `Tag'
This file contains per-directory sticky tags or dates.
The first character is `T' for a branch tag,
`N' for a non-branch tag, or `D' for a date,
or another character to mean the file should be
silently ignored, for future expansion. This character
is followed by the tag or date. Note that
per-directory sticky tags or dates are used for things
like applying to files which are newly added; they
might not be the same as the sticky tags or dates on
individual files. For general information on sticky
tags and dates, see Sticky tags.
- `Notify'
This file stores notifications (for example, for
edit or unedit) which have not yet been
sent to the server. Its format is not yet documented
here.
- `Notify.tmp'
This file is to `Notify' as `Entries.Backup'
is to `Entries'. That is, to write `Notify',
first write the new contents to `Notify.tmp' and
then (atomically where possible), rename it to
`Notify'.
- `Base'
If watches are in use, then an edit command
stores the original copy of the file in the `Base'
directory. This allows the unedit command to
operate even if it is unable to communicate with the
server.
- `Baserev'
The file lists the revision for each of the files in
the `Base' directory. The format is:
where expansion should be ignored, to allow for
future expansion.
- `Baserev.tmp'
This file is to `Baserev' as `Entries.Backup'
is to `Entries'. That is, to write `Baserev',
first write the new contents to `Baserev.tmp' and
then (atomically where possible), rename it to
`Baserev'.
- `Template'
This file contains the template specified by the
`rcsinfo' file (see section Rcsinfo). It is only used
by the client; the non-client/server CVS consults
`rcsinfo' directly.
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