Implement directory download as ZIP

Thanks to the fdzipstream library [1] and zlib [2], it is possible to
generate ZIP files on-the-fly, therefore requiring no extra disk space
usage and only a small amount of memory.

Unfortunately, as of the time of this writing fdzipstream is not
packaged by any distributions yet [3], so it had to be imported as a git
submodule as a workaround.

While libarchive [4] could be an interesting alternative, writing ZIP
files is only supported by very recent versions (>= 3.8.0), which are
still not packaged by many distributions [5], either.

Moreover, libarchive is a package with several dependencies other than
zlib and is significantly larger compared to fdzipstreams, so
fdzipstreams was ultimately considered a better fit for this purpose.

[1]: https://github.com/CTrabant/fdzipstream.git
[2]: http://zlib.net/
[3]: https://repology.org/projects/?search=fdzipstream
[4]: https://www.libarchive.org/
[5]: https://repology.org/project/libarchive/versions

1 files changed, 7 insertions, 7 deletions

diff --git a/main.c b/main.c
index 104a381..7a367b0 100644
--- a/main.c
+++ b/main.c
@@ -822,7 +822,7 @@ static int search(const struct http_payload *const p,
     *r = (const struct http_response)
     {
         .step.payload = search_step,
-        .step_args = s
+        .args = s
     };
 
     s->search.root = s->root.str;
@@ -1014,10 +1014,10 @@ static int check_quota(const unsigned long long len,
 
 static int check_length_step(const unsigned long long len,
     const struct http_cookie *const c, struct http_response *const r,
-    void *const user, void *const step_args)
+    void *const user, void *const args)
 {
     int ret = 0;
-    struct quota *const q = step_args;
+    struct quota *const q = args;
 
     switch (cftw_step(q->cftw))
     {
@@ -1079,7 +1079,7 @@ static int check_length(const unsigned long long len,
         *r = (const struct http_response)
         {
             .step.length = check_length_step,
-            .step_args = q
+            .args = q
         };
     }
 
@@ -1143,10 +1143,10 @@ end:
 }
 
 static int getnode_step(const struct http_payload *const p,
-    struct http_response *const r, void *const user, void *const step_args)
+    struct http_response *const r, void *const user, void *const args)
 {
     int ret = 0;
-    struct quota *const q = step_args;
+    struct quota *const q = args;
 
     switch (cftw_step(q->cftw))
     {
@@ -1214,7 +1214,7 @@ static int getnode(const struct http_payload *const p,
         *r = (const struct http_response)
         {
             .step.payload = getnode_step,
-            .step_args = q
+            .args = q
         };
     }
     else