journal-import: extract helpers for handling arrays of iovec and make them available for others

src/basic/io-util.c

@@ -270,3 +270,56 @@ char* set_iovec_string_field_free(struct iovec *iovec, size_t *n_iovec, const ch
         free(value);
         return x;
 }
+
+struct iovec_wrapper *iovw_new(void) {
+        return malloc0(sizeof(struct iovec_wrapper));
+}
+
+void iovw_free_contents(struct iovec_wrapper *iovw, bool free_vectors) {
+        if (free_vectors)
+                for (size_t i = 0; i < iovw->count; i++)
+                        free(iovw->iovec[i].iov_base);
+
+        iovw->iovec = mfree(iovw->iovec);
+        iovw->count = 0;
+        iovw->size_bytes = 0;
+}
+
+struct iovec_wrapper *iovw_free_free(struct iovec_wrapper *iovw) {
+        iovw_free_contents(iovw, true);
+
+        return mfree(iovw);
+}
+
+struct iovec_wrapper *iovw_free(struct iovec_wrapper *iovw) {
+        iovw_free_contents(iovw, false);
+
+        return mfree(iovw);
+}
+
+int iovw_put(struct iovec_wrapper *iovw, void *data, size_t len) {
+        if (iovw->count >= IOV_MAX)
+                return -E2BIG;
+
+        if (!GREEDY_REALLOC(iovw->iovec, iovw->size_bytes, iovw->count + 1))
+                return log_oom();
+
+        iovw->iovec[iovw->count++] = IOVEC_MAKE(data, len);
+        return 0;
+}
+
+void iovw_rebase(struct iovec_wrapper *iovw, char *old, char *new) {
+        size_t i;
+
+        for (i = 0; i < iovw->count; i++)
+                iovw->iovec[i].iov_base = (char *)iovw->iovec[i].iov_base - old + new;
+}
+
+size_t iovw_size(struct iovec_wrapper *iovw) {
+        size_t n = 0, i;
+
+        for (i = 0; i < iovw->count; i++)
+                n += iovw->iovec[i].iov_len;
+
+        return n;
+}

src/basic/io-util.h

@@ -74,3 +74,17 @@ static inline bool FILE_SIZE_VALID_OR_INFINITY(uint64_t l) {
 
 char* set_iovec_string_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value);
 char* set_iovec_string_field_free(struct iovec *iovec, size_t *n_iovec, const char *field, char *value);
+
+struct iovec_wrapper {
+        struct iovec *iovec;
+        size_t count;
+        size_t size_bytes;
+};
+
+struct iovec_wrapper *iovw_new(void);
+struct iovec_wrapper *iovw_free(struct iovec_wrapper *iovw);
+struct iovec_wrapper *iovw_free_free(struct iovec_wrapper *iovw);
+void iovw_free_contents(struct iovec_wrapper *iovw, bool free_vectors);
+int iovw_put(struct iovec_wrapper *iovw, void *data, size_t len);
+void iovw_rebase(struct iovec_wrapper *iovw, char *old, char *new);
+size_t iovw_size(struct iovec_wrapper *iovw);