c-ipfs/merkledag/merkledag.c
jmjatlanta c2fe60949e Added the ability to retrieve the file using directories
Files can be refered to directly using their hash, or the hash of their
directory and the file name.
2016-12-29 19:05:44 -05:00

90 lines
2.6 KiB
C

/**
* A basic storage building block of the IPFS system
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libp2p/crypto/sha256.h"
#include "mh/multihash.h"
#include "mh/hashes.h"
#include "ipfs/merkledag/merkledag.h"
#include "ipfs/unixfs/unixfs.h"
/***
* Adds a node to the dagService and blockService
* @param node the node to add
* @param fs_repo the repo to add to
* @param bytes_written the number of bytes written
* @returns true(1) on success
*/
int ipfs_merkledag_add(struct Node* node, struct FSRepo* fs_repo, size_t* bytes_written) {
// taken from merkledag.go line 59
int retVal = 0;
// compute the hash if necessary
if (node->hash == NULL) {
size_t protobuf_size = ipfs_node_protobuf_encode_size(node);
unsigned char protobuf[protobuf_size];
size_t bytes_encoded;
retVal = ipfs_node_protobuf_encode(node, protobuf, protobuf_size, &bytes_encoded);
node->hash_size = 32;
node->hash = (unsigned char*)malloc(node->hash_size);
if (node->hash == NULL) {
return 0;
}
if (libp2p_crypto_hashing_sha256(protobuf, bytes_encoded, &node->hash[0]) == 0) {
free(node->hash);
return 0;
}
}
// write to block store & datastore
retVal = ipfs_repo_fsrepo_node_write(node, fs_repo, bytes_written);
if (retVal == 0) {
return 0;
}
// TODO: call HasBlock (unsure why as yet)
return 1;
}
/***
* Retrieves a node from the datastore based on the hash
* @param hash the key to look for
* @param hash_size the length of the key
* @param node the node to be created
* @param fs_repo the repository
* @returns true(1) on success
*/
int ipfs_merkledag_get(const unsigned char* hash, size_t hash_size, struct Node** node, const struct FSRepo* fs_repo) {
int retVal = 1;
size_t key_length = 100;
unsigned char key[key_length];
// look for the node in the datastore. If it is not there, it is not a node.
// If it exists, it is only a block.
retVal = fs_repo->config->datastore->datastore_get((char*)hash, hash_size, key, key_length, &key_length, fs_repo->config->datastore);
if (retVal == 0)
return 0;
// we have the record from the db. Go get the node from the blockstore
retVal = ipfs_repo_fsrepo_node_read(hash, hash_size, node, fs_repo);
if (retVal == 0) {
return 0;
}
return 1;
}
int ipfs_merkledag_get_by_multihash(const unsigned char* multihash, size_t multihash_length, struct Node** node, const struct FSRepo* fs_repo) {
// convert to hash
size_t hash_size = 0;
unsigned char* hash = NULL;
if (mh_multihash_digest(multihash, multihash_length, &hash, &hash_size) < 0) {
return 0;
}
return ipfs_merkledag_get(hash, hash_size, node, fs_repo);
}