feat(file): added saving a file snapshot to the object database

src/file.c

@@ -67,3 +67,74 @@ File* slice_file(File* original, uint64_t start, uint64_t end) {
     slice->lines = lines;
     return slice;
 }
+
+int snapshot_file(char* path, char* root, size_t basefile_id, char* hash) {
+    File* file = new_file(path);
+    if (!file) return 1;
+
+    char** content = file->content;
+    size_t lines = file->lines;
+    size_t total_len = 0;
+    for (size_t i = 0; i < lines; i++) {
+        total_len += strlen(content[i]);
+        if (i < lines - 1) {
+            total_len++;
+        }
+    }
+    total_len += 1;
+
+    char* concat_file = calloc(total_len, sizeof(char));
+    if (!concat_file) return 1;
+
+    strcpy(concat_file, content[0]);
+    for (size_t i = 1; i < lines; i++) {
+        strcat(concat_file, "\n");
+        strcat(concat_file, content[i]);
+    }
+
+    char id[2+snprintf(NULL, 0, "%d", basefile_id)+strlen(path)];
+    snprintf(id, sizeof(id), "%s_%d", path, basefile_id);
+    object_hash(FileObject, id, hash);
+
+    char dir_path[PATH_MAX];
+    char file_path[PATH_MAX];
+    snprintf(dir_path, sizeof(dir_path), "%s/.merk/objects/%.2s", root, hash);
+    mkdir(dir_path, 0755);
+    snprintf(file_path, sizeof(file_path), "%s/%s", dir_path, hash+2);
+
+    FILE* fp = fopen(file_path, "wb");
+    if (!fp) {
+        perror("ERROR: cannot open path in snapshot_file!\n");
+        free(concat_file);
+        return 1;
+    }
+
+    uLong originalLen = strlen(concat_file) + 1;
+    uLong compressedLen = compressBound(originalLen);
+    Bytef* compressed = malloc(compressedLen);
+    if (!compressed) {
+        fclose(fp);
+        free(concat_file);
+        return 1;
+    }
+
+    if (compress(compressed, &compressedLen, (const Bytef*)concat_file, originalLen) != Z_OK) {
+        perror("ERROR: compression failed in snapshot_file!");
+        free(compressed);
+        free(concat_file);
+        fclose(fp);
+        return 1;
+    }
+
+    fprintf(fp, "%lu ", (unsigned long)originalLen);
+
+    fwrite(compressed, 1, compressedLen, fp);
+
+    fclose(fp);
+
+    chmod(file_path, S_IRUSR | S_IRGRP | S_IROTH);
+
+    free(compressed);
+    free(concat_file);
+    return 0;
+}