netcdf-c/include/ncuri.h
Dennis Heimbigner 59e04ae071 This PR adds EXPERIMENTAL support for accessing data in the
cloud using a variant of the Zarr protocol and storage
format. This enhancement is generically referred to as "NCZarr".

The data model supported by NCZarr is netcdf-4 minus the user-defined
types and the String type. In this sense it is similar to the CDF-5
data model.

More detailed information about enabling and using NCZarr is
described in the document NUG/nczarr.md and in a
[Unidata Developer's blog entry](https://www.unidata.ucar.edu/blogs/developer/en/entry/overview-of-zarr-support-in).

WARNING: this code has had limited testing, so do use this version
for production work. Also, performance improvements are ongoing.
Note especially the following platform matrix of successful tests:

Platform | Build System | S3 support
------------------------------------
Linux+gcc      | Automake     | yes
Linux+gcc      | CMake        | yes
Visual Studio  | CMake        | no

Additionally, and as a consequence of the addition of NCZarr,
major changes have been made to the Filter API. NOTE: NCZarr
does not yet support filters, but these changes are enablers for
that support in the future.  Note that it is possible
(probable?) that there will be some accidental reversions if the
changes here did not correctly mimic the existing filter testing.

In any case, previously filter ids and parameters were of type
unsigned int. In order to support the more general zarr filter
model, this was all converted to char*.  The old HDF5-specific,
unsigned int operations are still supported but they are
wrappers around the new, char* based nc_filterx_XXX functions.
This entailed at least the following changes:
1. Added the files libdispatch/dfilterx.c and include/ncfilter.h
2. Some filterx utilities have been moved to libdispatch/daux.c
3. A new entry, "filter_actions" was added to the NCDispatch table
   and the version bumped.
4. An overly complex set of structs was created to support funnelling
   all of the filterx operations thru a single dispatch
   "filter_actions" entry.
5. Move common code to from libhdf5 to libsrc4 so that it is accessible
   to nczarr.

Changes directly related to Zarr:
1. Modified CMakeList.txt and configure.ac to support both C and C++
   -- this is in support of S3 support via the awd-sdk libraries.
2. Define a size64_t type to support nczarr.
3. More reworking of libdispatch/dinfermodel.c to
   support zarr and to regularize the structure of the fragments
   section of a URL.

Changes not directly related to Zarr:
1. Make client-side filter registration be conditional, with default off.
2. Hack include/nc4internal.h to make some flags added by Ed be unique:
   e.g. NC_CREAT, NC_INDEF, etc.
3. cleanup include/nchttp.h and libdispatch/dhttp.c.
4. Misc. changes to support compiling under Visual Studio including:
   * Better testing under windows for dirent.h and opendir and closedir.
5. Misc. changes to the oc2 code to support various libcurl CURLOPT flags
   and to centralize error reporting.
6. By default, suppress the vlen tests that have unfixed memory leaks; add option to enable them.
7. Make part of the nc_test/test_byterange.sh test be contingent on remotetest.unidata.ucar.edu being accessible.

Changes Left TO-DO:
1. fix provenance code, it is too HDF5 specific.
2020-06-28 18:02:47 -06:00

113 lines
3.7 KiB
C

/*
* Copyright 2018, University Corporation for Atmospheric Research
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
*/
#ifndef NCURI_H
#define NCURI_H
/* Define flags to control what is included by ncuribuild*/
#define NCURIPATH 1
#define NCURIPWD 2
#define NCURIQUERY 4
#define NCURIFRAG 8
#define NCURIENCODE 16 /* If output should be encoded */
#define NCURIBASE (NCURIPWD|NCURIPATH)
#define NCURISVC (NCURIQUERY|NCURIBASE) /* for sending to server */
#define NCURIALL (NCURIPATH|NCURIPWD|NCURIQUERY|NCURIFRAG) /* for rebuilding after changes */
/*! This is an open structure meaning
it is ok to directly access its fields
*/
typedef struct NCURI {
char* uri; /* copy of url as passed by the caller */
char* protocol;
char* user; /* from user:password@ */
char* password; /* from user:password@ */
char* host; /*!< host*/
char* port; /*!< port */
char* path; /*!< path */
char* query; /*!< query */
char* fragment; /*!< fragment */
char** fraglist; /* envv style list of decomposed fragment*/
char** querylist; /* envv style list of decomposed query*/
#if 0
char* projection; /*!< without leading '?'*/
char* selection; /*!< with leading '&'*/
#endif
} NCURI;
/* Declaration modifiers for DLL support (MSC et al) */
#if defined(DLL_NETCDF) /* define when library is a DLL */
# if defined(DLL_EXPORT) /* define when building the library */
# define MSC_EXTRA __declspec(dllexport)
# else
# define MSC_EXTRA __declspec(dllimport)
# endif
# include <io.h>
#else
#define MSC_EXTRA /**< Needed for DLL build. */
#endif /* defined(DLL_NETCDF) */
#define EXTERNL MSC_EXTRA extern /**< Needed for DLL build. */
#if defined(_CPLUSPLUS_) || defined(__CPLUSPLUS__) || defined(__CPLUSPLUS)
extern "C" {
#endif
EXTERNL int ncuriparse(const char* s, NCURI** ncuri);
EXTERNL void ncurifree(NCURI* ncuri);
/* Replace the protocol */
EXTERNL int ncurisetprotocol(NCURI*,const char* newprotocol);
/* Replace the constraints */
EXTERNL int ncurisetquery(NCURI*,const char* query);
/* Replace the fragment list */
EXTERNL int ncurisetfragments(NCURI*, const char* fragments);
/* Replace a specific &key=...& in uri fragment */
EXTERNL int ncurisetfragmentkey(NCURI* duri,const char* key, const char* value);
/* append a specific &key=...& in uri fragment */
EXTERNL int ncuriappendfragmentkey(NCURI* duri,const char* key, const char* value);
/* Construct a complete NC URI; caller frees returned string */
EXTERNL char* ncuribuild(NCURI*,const char* prefix, const char* suffix, int flags);
/*! Search the fragment for a given parameter
Null result => entry not found; !NULL=>found;
In any case, the result is imutable and should not be free'd.
*/
EXTERNL const char* ncurifragmentlookup(NCURI*, const char* param);
/*! Search the query for a given parameter
Null result => entry not found; !NULL=>found;
In any case, the result is imutable and should not be free'd.
*/
EXTERNL const char* ncuriquerylookup(NCURI*, const char* param);
/* Obtain the complete list of fragment pairs in envv format */
EXTERNL const char** ncurifragmentparams(NCURI*);
/* Obtain the complete list of query pairs in envv format */
EXTERNL const char** ncuriqueryparams(NCURI*);
/* URL Encode/Decode */
EXTERNL char* ncuridecode(const char* s);
/* Partial decode */
EXTERNL char* ncuridecodepartial(const char* s, const char* decodeset);
/* Encode using specified character set */
EXTERNL char* ncuriencodeonly(const char* s, const char* allowable);
/* Encode user or pwd */
EXTERNL char* ncuriencodeuserpwd(const char* s);
#if defined(_CPLUSPLUS_) || defined(__CPLUSPLUS__) || defined(__CPLUSPLUS)
}
#endif
#endif /*NCURI_H*/