c-ipfs/path/resolver.c

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C
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#include "ipfs/cid/cid.h"
#include "ipfs/path/path.h"
Resolver* ipfs_path_new_basic_resolver (DAGService *ds)
{
Resolver *ret = malloc(sizeof(Resolver));
if (!ret) return NULL;
ret->DAG = ds;
ret->ResolveOnce = ipfs_path_resolve_single;
return ret;
}
// ipfs_path_split_abs_path clean up and split fpath. It extracts the first component (which
// must be a Multihash) and return it separately.
int ipfs_path_split_abs_path (struct Cid* cid, char ***parts, char *fpath)
{
*parts = ipfs_path_split_segments(fpath);
if (strcmp (**parts, "ipfs") == 0) *parts++;
// if nothing, bail.
if (!**parts) return ErrNoComponents;
// first element in the path is a cid
cid_decode_from_string(**parts, strlen(**parts), cid);
return 0;
}
// ipfs_path_resolve_path fetches the node for given path. It returns the last item
// returned by ipfs_path_resolve_path_components.
int ipfs_path_resolve_path(Node **nd, Context ctx, Resolver *s, char *fpath)
{
int err = IsValid(fpath);
Node **ndd;
if (err) {
return err;
}
err = ipfs_path_resolve_path_components(&ndd, ctx, s, fpath);
if (err) {
return err;
}
if (ndd == NULL) {
return ErrBadPath;
}
while(*ndd) {
*nd = *ndd;
ndd++;
}
return 0;
}
int ipfs_path_resolve_single(NodeLink **lnk, Context ctx, DAGService *ds, Node **nd, char *name)
{
return ipfs_path_resolve_link(lnk, name);
}
// ipfs_path_resolve_path_components fetches the nodes for each segment of the given path.
// It uses the first path component as a hash (key) of the first node, then
// resolves all other components walking the links, with ipfs_path_resolve_links.
int ipfs_path_resolve_path_components(Node ***nd, Context ctx, Resolver *s, char *fpath)
{
int err;
struct Cid h;
char **parts;
err = ipfs_path_split_abs_path(&h, &parts, fpath);
if (err) {
return err;
}
//log.Debug("resolve dag get");
//*nd = s->DAG.Get(ctx, h);
//if (nd == DAG_ERR_VAL) {
// return DAG_ERR_VAL;
//}
return ipfs_path_resolve_links(ctx, *nd, parts);
}
// ipfs_path_resolve_links iteratively resolves names by walking the link hierarchy.
// Every node is fetched from the DAGService, resolving the next name.
// Returns the list of nodes forming the path, starting with ndd. This list is
// guaranteed never to be empty.
//
// ipfs_path_resolve_links(nd, []string{"foo", "bar", "baz"})
// would retrieve "baz" in ("bar" in ("foo" in nd.Links).Links).Links
int ipfs_path_resolve_links(Node ***result, Context ctx, Node *ndd, char **names)
{
int err, idx = 0, l;
NodeLink *lnk;
Node *nd;
*result = calloc (sizeof(Node*), ipfs_path_segments_length(names) + 1);
if (!*result) {
return -1;
}
memset (*result, NULL, sizeof(Node*) * (ipfs_path_segments_length(names)+1));
*result[idx++] = ndd;
nd = ndd; // dup arg workaround
while (*names) {
//TODO
//var cancel context.CancelFunc
//ctx, cancel = context.WithTimeout(ctx, time.Minute)
//defer cancel()
// for each of the path components
err = ipfs_path_resolve_link(&lnk, *names);
if (err) {
char msg[51];
*result[idx] = NULL;
snprintf(msg, sizeof(msg), ErrPath[ErrNoLinkFmt], *names, nd->Cid);
if (ErrPath[ErrNoLink]) {
free(ErrPath[ErrNoLink]);
}
l = strlen(msg) + 1;
ErrPath[ErrNoLink] = malloc(l);
if (ErrPath[ErrNoLink]) {
memcpy(ErrPath[ErrNoLink], msg, l);
}
free (*result);
return ErrNoLink;
}
names++;
}
return 0;
}