Partially address: https://github.com/Unidata/netcdf-c/issues/1056
Currently, some of the entries in the dispatch table
are conditional'd on USE_NETCDF4.
As a step in upgrading the dispatch table for use
with user-defined tables, we remove that conditional.
This means that all dispatch tables must implement the
netcdf-4 specific functions even if only to make them
return NC_ENOTNC4. To simplify this, a set of default
functions are defined in libdispatch/dnotnc4.c to provide this
behavior. The file libdispatch/dnotnc3.c is also relevant to
this.
The primary fix is to modify the various dispatch tables to
remove the conditional and use the functions in
libdispatch/dnotnc4.c as appropriate. In practice, all of the
existing tables are prepared to handle this, so the only
real change is to remove the conditionals.
Misc. Unrelated fixes
1. Fix some annoying warnings in ncvalidator.
Notes:
1. This has not been tested with either pnetcdf or hdf4 enabled.
When those are enabled, it is possible that there are still
some conditionals that need to be fixed.
This fixes an issue hit by GDAL, and that is found in netcdf 4.6.3
and 4.7.0
git bisect pointed the problem to have started with
```
77ab979c5f is the first bad commit
commit 77ab979c5f
Author: Ed Hartnett <edwardjameshartnett@gmail.com>
Date: Sat Jun 16 09:58:48 2018 -0600
using get_vars but not put_vars
:040000 040000 8611e77aaefc9ffd1d13 M libsrc4
```
where nc_get_vara_double() started using nc4_get_vars() underneath.
It turns out that nc4_get_vars() was buggy in the situation exercised by GDAL.
This can be reproduced with the following simple test case:
```
int main()
{
int status;
int cdfid = -1;
int first_dim;
int varid;
int other_var;
size_t anStart[NC_MAX_DIMS];
size_t anCount[NC_MAX_DIMS];
double* val = (double*)calloc(3, sizeof(double));
status = nc_create("foo.nc", NC_NETCDF4, &cdfid);
assert( status == NC_NOERR );
status = nc_def_dim(cdfid, "unlimited_dim", NC_UNLIMITED, &first_dim);
assert( status == NC_NOERR );
status = nc_def_var(cdfid, "my_var", NC_DOUBLE, 1, &first_dim, &varid);
assert( status == NC_NOERR );
status = nc_def_var(cdfid, "other_var", NC_DOUBLE, 1, &first_dim, &other_var);
assert( status == NC_NOERR );
status = nc_enddef(cdfid);
assert( status == NC_NOERR );
/* Write 3 elements to set the size of the unlimited dim to 3 */
anStart[0] = 0;
anCount[0] = 3;
status = nc_put_vara_double(cdfid, other_var, anStart, anCount, val);
assert( status == NC_NOERR );
/* Read 2 elements starting with index=1 */
anStart[0] = 1;
anCount[0] = 2;
status = nc_get_vara_double(cdfid, varid, anStart, anCount, val);
assert( status == NC_NOERR );
status = nc_close(cdfid);
assert( status == NC_NOERR );
free(val);
return 0;
}
```
Running it under Valgrind without this patch leads to
```
==19637==
==19637== Invalid write of size 8
==19637== at 0x4C326CB: memcpy@@GLIBC_2.14 (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==19637== by 0x4EDBE3D: NC4_get_vars (hdf5var.c:2131)
==19637== by 0x4EDA24C: NC4_get_vara (hdf5var.c:1342)
==19637== by 0x4E68878: NC_get_vara (dvarget.c:104)
==19637== by 0x4E69FDB: nc_get_vara_double (dvarget.c:815)
==19637== by 0x400C08: main (in /home/even/netcdf-c/build/test)
==19637== Address 0xb70e3e8 is 8 bytes before a block of size 24 alloc'd
==19637== at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==19637== by 0x4009E8: main (in /home/even/netcdf-c/build/test)
==19637==
```
re: github issue #1425
The 'ncdump -v' command causes a constraint to be sent
to the opendap code (in libdap2). This is a separate path
from specifying the constraint via a URL.
This separate path encoded its constraint using code independent
of and duplicative of that provided by ncuri.c and this duplicate
code did not properly encode the constraint, which might include
square brackets.
Solution chosen here was to get rid of the duplicate code and
ensure that all URL escaping is performed in the ncuribuild function
in the ncuri.c file.
Also removed the use of the NEWESCAPE conditional in ncuri.c
because it is no longer needed.
re: issue https://github.com/Unidata/netcdf-c/issues/1436
It used to be that when no -c parameters were specified
(and the input was some variant of netcdf-3) that nccopy
let the netcdf-c library decide on any default chunking.
Now, it attempts to do it itself and is not doing it
correctly when unlimited dimensions are involved.
So fix is to revert to previous behavior.
Note: The chunking rules are getting too complicated; consider revising.
