netcdf-c/libnczarr/zarr.c
Dennis Heimbigner 231ae96c4b Add support for Zarr string type to NCZarr
* re: https://github.com/Unidata/netcdf-c/pull/2278
* re: https://github.com/Unidata/netcdf-c/issues/2485
* re: https://github.com/Unidata/netcdf-c/issues/2474

This PR subsumes PR https://github.com/Unidata/netcdf-c/pull/2278.
Actually is a bit an omnibus covering several issues.

## PR https://github.com/Unidata/netcdf-c/pull/2278
Add support for the Zarr string type.
Zarr strings are restricted currently to be of fixed size.
The primary issue to be addressed is to provide a way for user to
specify the size of the fixed length strings. This is handled by providing
the following new attributes special:
1. **_nczarr_default_maxstrlen** —
This is an attribute of the root group. It specifies the default
maximum string length for string types. If not specified, then
it has the value of 64 characters.
2. **_nczarr_maxstrlen** —
This is a per-variable attribute. It specifies the maximum
string length for the string type associated with the variable.
If not specified, then it is assigned the value of
**_nczarr_default_maxstrlen**.

This PR also requires some hacking to handle the existing netcdf-c NC_CHAR
type, which does not exist in zarr. The goal was to choose numpy types for
both the netcdf-c NC_STRING type and the netcdf-c NC_CHAR type such that
if a pure zarr implementation read them, it would still work and an
NC_CHAR type would be handled by zarr as a string of length 1.

For writing variables and NCZarr attributes, the type mapping is as follows:
* "|S1" for NC_CHAR.
* ">S1" for NC_STRING && MAXSTRLEN==1
* ">Sn" for NC_STRING && MAXSTRLEN==n

Note that it is a bit of a hack to use endianness, but it should be ok since for
string/char, the endianness has no meaning.

For reading attributes with pure zarr (i.e. with no nczarr
atribute types defined), they will always be interpreted as of
type NC_CHAR.

## Issue: https://github.com/Unidata/netcdf-c/issues/2474
This PR partly fixes this issue because it provided more
comprehensive support for Zarr attributes that are JSON valued expressions.
This PR still does not address the problem in that issue where the
_ARRAY_DIMENSION attribute is incorrectly set. Than can only be
fixed by the creator of the datasets.

## Issue: https://github.com/Unidata/netcdf-c/issues/2485
This PR also fixes the scalar failure shown in this issue.
It generally cleans up scalar handling.
It also adds a note to the documentation describing that
NCZarr supports scalars while Zarr does not and also how
scalar interoperability is achieved.

## Misc. Other Changes
1. Convert the nczarr special attributes and keys to be all lower case. So "_NCZARR_ATTR" now used "_nczarr_attr. Support back compatibility for the upper case names.
2. Cleanup my too-clever-by-half handling of scalars in libnczarr.
2022-08-27 20:21:13 -06:00

424 lines
12 KiB
C

/*********************************************************************
* Copyright 2018, UCAR/Unidata
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
*********************************************************************/
#include "zincludes.h"
/**************************************************/
/* Forwards */
static int applycontrols(NCZ_FILE_INFO_T* zinfo);
/***************************************************/
/* API */
/**
@internal Create the topmost dataset object and setup up
NCZ_FILE_INFO_T state.
@param zinfo - [in] the internal state
@return NC_NOERR
@author Dennis Heimbigner
*/
int
ncz_create_dataset(NC_FILE_INFO_T* file, NC_GRP_INFO_T* root, const char** controls)
{
int stat = NC_NOERR;
NCZ_FILE_INFO_T* zinfo = NULL;
NCZ_GRP_INFO_T* zgrp = NULL;
NCURI* uri = NULL;
NC* nc = NULL;
NCjson* json = NULL;
char* key = NULL;
ZTRACE(3,"file=%s root=%s controls=%s",file->hdr.name,root->hdr.name,(controls?nczprint_envv(controls):"null"));
nc = (NC*)file->controller;
/* Add struct to hold NCZ-specific file metadata. */
if (!(zinfo = calloc(1, sizeof(NCZ_FILE_INFO_T))))
{stat = NC_ENOMEM; goto done;}
file->format_file_info = zinfo;
zinfo->common.file = file;
/* Add struct to hold NCZ-specific group info. */
if (!(zgrp = calloc(1, sizeof(NCZ_GRP_INFO_T))))
{stat = NC_ENOMEM; goto done;}
root->format_grp_info = zgrp;
zgrp->common.file = file;
/* Fill in NCZ_FILE_INFO_T */
zinfo->created = 1;
zinfo->common.file = file;
zinfo->native_endianness = (NCZ_isLittleEndian() ? NC_ENDIAN_LITTLE : NC_ENDIAN_BIG);
if((zinfo->envv_controls=NCZ_clonestringvec(0,controls)) == NULL)
{stat = NC_ENOMEM; goto done;}
/* fill in some of the zinfo and zroot fields */
zinfo->zarr.zarr_version = atoi(ZARRVERSION);
sscanf(NCZARRVERSION,"%lu.%lu.%lu",
&zinfo->zarr.nczarr_version.major,
&zinfo->zarr.nczarr_version.minor,
&zinfo->zarr.nczarr_version.release);
zinfo->default_maxstrlen = NCZ_MAXSTR_DEFAULT;
/* Apply client controls */
if((stat = applycontrols(zinfo))) goto done;
/* Load auth info from rc file */
if((stat = ncuriparse(nc->path,&uri))) goto done;
if(uri) {
if((stat = NC_authsetup(&zinfo->auth, uri)))
goto done;
}
/* initialize map handle*/
if((stat = nczmap_create(zinfo->controls.mapimpl,nc->path,nc->mode,zinfo->controls.flags,NULL,&zinfo->map)))
goto done;
done:
ncurifree(uri);
NCJreclaim(json);
nullfree(key);
return ZUNTRACE(stat);
}
/**
@internal Open the topmost dataset object.
@param file - [in] the file struct
@param controls - [in] the fragment list in envv form from uri
@return NC_NOERR
@author Dennis Heimbigner
*/
int
ncz_open_dataset(NC_FILE_INFO_T* file, const char** controls)
{
int stat = NC_NOERR;
NC* nc = NULL;
NC_GRP_INFO_T* root = NULL;
NCURI* uri = NULL;
void* content = NULL;
NCjson* json = NULL;
NCZ_FILE_INFO_T* zinfo = NULL;
int mode;
NClist* modeargs = NULL;
char* nczarr_version = NULL;
char* zarr_format = NULL;
ZTRACE(3,"file=%s controls=%s",file->hdr.name,(controls?nczprint_envv(controls):"null"));
/* Extract info reachable via file */
nc = (NC*)file->controller;
mode = nc->mode;
root = file->root_grp;
assert(root != NULL && root->hdr.sort == NCGRP);
/* Add struct to hold NCZ-specific file metadata. */
if (!(file->format_file_info = calloc(1, sizeof(NCZ_FILE_INFO_T))))
{stat = NC_ENOMEM; goto done;}
zinfo = file->format_file_info;
/* Fill in NCZ_FILE_INFO_T */
zinfo->created = 0;
zinfo->common.file = file;
zinfo->native_endianness = (NCZ_isLittleEndian() ? NC_ENDIAN_LITTLE : NC_ENDIAN_BIG);
if((zinfo->envv_controls = NCZ_clonestringvec(0,controls))==NULL) /*0=>envv style*/
{stat = NC_ENOMEM; goto done;}
zinfo->default_maxstrlen = NCZ_MAXSTR_DEFAULT;
/* Add struct to hold NCZ-specific group info. */
if (!(root->format_grp_info = calloc(1, sizeof(NCZ_GRP_INFO_T))))
{stat = NC_ENOMEM; goto done;}
((NCZ_GRP_INFO_T*)root->format_grp_info)->common.file = file;
/* Apply client controls */
if((stat = applycontrols(zinfo))) goto done;
/* initialize map handle*/
if((stat = nczmap_open(zinfo->controls.mapimpl,nc->path,mode,zinfo->controls.flags,NULL,&zinfo->map)))
goto done;
if((stat = ncz_read_superblock(file,&nczarr_version,&zarr_format))) goto done;
if(nczarr_version == NULL) /* default */
nczarr_version = strdup(NCZARRVERSION);
if(zarr_format == NULL) /* default */
zarr_format = strdup(ZARRVERSION);
/* Extract the information from it */
if(sscanf(zarr_format,"%d",&zinfo->zarr.zarr_version)!=1)
{stat = NC_ENCZARR; goto done;}
if(sscanf(nczarr_version,"%lu.%lu.%lu",
&zinfo->zarr.nczarr_version.major,
&zinfo->zarr.nczarr_version.minor,
&zinfo->zarr.nczarr_version.release) == 0)
{stat = NC_ENCZARR; goto done;}
/* Load auth info from rc file */
if((stat = ncuriparse(nc->path,&uri))) goto done;
if(uri) {
if((stat = NC_authsetup(&zinfo->auth, uri)))
goto done;
}
done:
nullfree(zarr_format);
nullfree(nczarr_version);
ncurifree(uri);
nclistfreeall(modeargs);
if(json) NCJreclaim(json);
nullfree(content);
return ZUNTRACE(stat);
}
/**
* @internal Determine whether file is netCDF-4.
*
* For libzarr, this is always true.
*
* @param h5 Pointer to HDF5 file info struct.
*
* @returns NC_NOERR No error.
* @author Dennis Heimbigner.
*/
int
NCZ_isnetcdf4(struct NC_FILE_INFO* h5)
{
int isnc4 = 1;
NC_UNUSED(h5);
return isnc4;
}
/**
* @internal Determine version info
*
* For libzarr, this is not well defined
*
* @param majorp Pointer to major version number
* @param minorp Pointer to minor version number
* @param releasep Pointer to release version number
*
* @returns NC_NOERR No error.
* @author Dennis Heimbigner.
*/
int
NCZ_get_libversion(unsigned long* majorp, unsigned long* minorp,unsigned long* releasep)
{
unsigned long m0,m1,m2;
sscanf(NCZARRVERSION,"%lu.%lu.%lu",&m0,&m1,&m2);
if(majorp) *majorp = m0;
if(minorp) *minorp = m1;
if(releasep) *releasep = m2;
return NC_NOERR;
}
/**
* @internal Determine "superblock" number.
*
* For libzarr, use the value of the major part of the nczarr version.
*
* @param superblocp Pointer to place to return superblock.
* use the nczarr format version major as the superblock number.
*
* @returns NC_NOERR No error.
* @author Dennis Heimbigner.
*/
int
NCZ_get_superblock(NC_FILE_INFO_T* file, int* superblockp)
{
NCZ_FILE_INFO_T* zinfo = file->format_file_info;
if(superblockp) *superblockp = zinfo->zarr.nczarr_version.major;
return NC_NOERR;
}
/**************************************************/
/* Utilities */
#if 0
/**
@internal Open the root group object
@param dataset - [in] the root dataset object
@param rootp - [out] created root group
@return NC_NOERR
@author Dennis Heimbigner
*/
static int
ncz_open_rootgroup(NC_FILE_INFO_T* dataset)
{
int stat = NC_NOERR;
int i;
NCZ_FILE_INFO_T* zfile = NULL;
NC_GRP_INFO_T* root = NULL;
void* content = NULL;
char* rootpath = NULL;
NCjson* json = NULL;
ZTRACE(3,"dataset=",dataset->hdr.name);
zfile = dataset->format_file_info;
/* Root should already be defined */
root = dataset->root_grp;
assert(root != NULL);
if((stat=nczm_concat(NULL,ZGROUP,&rootpath)))
goto done;
if((stat = NCZ_downloadjson(zfile->map, rootpath, &json)))
goto done;
/* Process the json */
for(i=0;i<nclistlength(json->contents);i+=2) {
const NCjson* key = nclistget(json->contents,i);
const NCjson* value = nclistget(json->contents,i+1);
if(strcmp(NCJstring(key),"zarr_format")==0) {
int zversion;
if(sscanf(NCJstring(value),"%d",&zversion)!=1)
{stat = NC_ENOTNC; goto done;}
/* Verify against the dataset */
if(zversion != zfile->zarr.zarr_version)
{stat = NC_ENOTNC; goto done;}
}
}
done:
if(json) NCJreclaim(json);
nullfree(rootpath);
nullfree(content);
return ZUNTRACE(stat);
}
#endif
static const char*
controllookup(const char** envv_controls, const char* key)
{
const char** p;
for(p=envv_controls;*p;p+=2) {
if(strcasecmp(key,*p)==0) {
return p[1];
}
}
return NULL;
}
static int
applycontrols(NCZ_FILE_INFO_T* zinfo)
{
int i,stat = NC_NOERR;
const char* value = NULL;
NClist* modelist = nclistnew();
int noflags = 0; /* track non-default negative flags */
if((value = controllookup((const char**)zinfo->envv_controls,"mode")) != NULL) {
if((stat = NCZ_comma_parse(value,modelist))) goto done;
}
/* Process the modelist first */
zinfo->controls.mapimpl = NCZM_DEFAULT;
zinfo->controls.flags |= FLAG_XARRAYDIMS; /* Always support XArray convention where possible */
for(i=0;i<nclistlength(modelist);i++) {
const char* p = nclistget(modelist,i);
if(strcasecmp(p,PUREZARRCONTROL)==0)
zinfo->controls.flags |= (FLAG_PUREZARR);
else if(strcasecmp(p,XARRAYCONTROL)==0)
zinfo->controls.flags |= FLAG_PUREZARR;
else if(strcasecmp(p,NOXARRAYCONTROL)==0)
noflags |= FLAG_XARRAYDIMS;
else if(strcasecmp(p,"zip")==0) zinfo->controls.mapimpl = NCZM_ZIP;
else if(strcasecmp(p,"file")==0) zinfo->controls.mapimpl = NCZM_FILE;
else if(strcasecmp(p,"s3")==0) zinfo->controls.mapimpl = NCZM_S3;
}
/* Apply negative controls by turning off negative flags */
/* This is necessary to avoid order dependence of mode flags when both positive and negative flags are defined */
zinfo->controls.flags &= (~noflags);
/* Process other controls */
if((value = controllookup((const char**)zinfo->envv_controls,"log")) != NULL) {
zinfo->controls.flags |= FLAG_LOGGING;
ncsetlogging(1);
}
if((value = controllookup((const char**)zinfo->envv_controls,"show")) != NULL) {
if(strcasecmp(value,"fetch")==0)
zinfo->controls.flags |= FLAG_SHOWFETCH;
}
done:
nclistfreeall(modelist);
return stat;
}
#if 0
/**
@internal Rewrite attributes into a group or var
@param map - [in] the map object for storage
@param container - [in] the containing object
@param jattrs - [in] the json for .zattrs
@param jtypes - [in] the json for .ztypes
@return NC_NOERR
@author Dennis Heimbigner
*/
int
ncz_unload_jatts(NCZ_FILE_INFO_T* zinfo, NC_OBJ* container, NCjson* jattrs, NCjson* jtypes)
{
int stat = NC_NOERR;
char* fullpath = NULL;
char* akey = NULL;
char* tkey = NULL;
NCZMAP* map = zinfo->map;
assert((NCJsort(jattrs) == NCJ_DICT));
assert((NCJsort(jtypes) == NCJ_DICT));
if(container->sort == NCGRP) {
NC_GRP_INFO_T* grp = (NC_GRP_INFO_T*)container;
/* Get grp's fullpath name */
if((stat = NCZ_grpkey(grp,&fullpath)))
goto done;
} else {
NC_VAR_INFO_T* var = (NC_VAR_INFO_T*)container;
/* Get var's fullpath name */
if((stat = NCZ_varkey(var,&fullpath)))
goto done;
}
/* Construct the path to the .zattrs object */
if((stat = nczm_concat(fullpath,ZATTRS,&akey)))
goto done;
/* Always write as V2 */
{
NCjson* k = NULL;
NCjson* v = NULL;
/* remove any previous version */
if(!NCJremove(jattrs,NCZ_V2_ATTRS,1,&k,&v)) {
NCJreclaim(k); NCJreclaim(v);
}
}
if(!(zinfo->controls.flags & FLAG_PUREZARR)) {
/* Insert the jtypes into the set of attributes */
if((stat = NCJinsert(jattrs,NCZ_V2_ATTRS,jtypes))) goto done;
}
/* Upload the .zattrs object */
if((stat=NCZ_uploadjson(map,tkey,jattrs)))
goto done;
done:
if(stat) {
NCJreclaim(jattrs);
NCJreclaim(jtypes);
}
nullfree(fullpath);
nullfree(akey);
nullfree(tkey);
return stat;
}
#endif