Add multi_curl handle to ALPM global context

To be able to run multiple download in parallel efficiently we need to
use curl_multi interface [1]. It introduces a set of APIs over new type
of handler 'CURLM'.

Create CURLM object at the application start and set it to global ALPM
context.

The 'single-download' CURL handle moves to payload struct. A new CURL
handle is created for each payload with intention to be processed by CURLM.

Note that curl_download_internal() is not ported to CURLM interface due
to the fact that the function will go away soon.

[1] https://curl.haxx.se/libcurl/c/libcurl-multi.html

Signed-off-by: Allan McRae <allan@archlinux.org>

lib/libalpm/alpm.c

@@ -70,6 +70,11 @@ alpm_handle_t SYMEXPORT *alpm_initialize(const char *root, const char *dbpath,
 		goto cleanup;
 	}
 
+#ifdef HAVE_LIBCURL
+	curl_global_init(CURL_GLOBAL_ALL);
+	myhandle->curlm = curl_multi_init();
+#endif
+
 #ifdef ENABLE_NLS
 	bindtextdomain("libalpm", LOCALEDIR);
 #endif
@@ -104,13 +109,14 @@ int SYMEXPORT alpm_release(alpm_handle_t *myhandle)
 		ret = -1;
 	}
 
-	_alpm_handle_unlock(myhandle);
-	_alpm_handle_free(myhandle);
-
 #ifdef HAVE_LIBCURL
+	curl_multi_cleanup(myhandle->curlm);
 	curl_global_cleanup();
 #endif
 
+	_alpm_handle_unlock(myhandle);
+	_alpm_handle_free(myhandle);
+
 	return ret;
 }
 

lib/libalpm/dload.c

@@ -72,15 +72,6 @@ static char *get_fullpath(const char *path, const char *filename,
 	return filepath;
 }
 
-static CURL *get_libcurl_handle(alpm_handle_t *handle)
-{
-	if(!handle->curl) {
-		curl_global_init(CURL_GLOBAL_SSL);
-		handle->curl = curl_easy_init();
-	}
-	return handle->curl;
-}
-
 enum {
 	ABORT_SIGINT = 1,
 	ABORT_OVER_MAXFILESIZE
@@ -241,7 +232,7 @@ static size_t dload_parseheader_cb(void *ptr, size_t size, size_t nmemb, void *u
 		}
 	}
 
-	curl_easy_getinfo(payload->handle->curl, CURLINFO_RESPONSE_CODE, &respcode);
+	curl_easy_getinfo(payload->curl, CURLINFO_RESPONSE_CODE, &respcode);
 	if(payload->respcode != respcode) {
 		payload->respcode = respcode;
 	}
@@ -377,8 +368,9 @@ static int curl_download_internal(struct dload_payload *payload,
 	struct sigaction orig_sig_pipe, orig_sig_int;
 	/* shortcut to our handle within the payload */
 	alpm_handle_t *handle = payload->handle;
-	CURL *curl = get_libcurl_handle(handle);
+	CURL *curl = curl_easy_init();
 	handle->pm_errno = ALPM_ERR_OK;
+	payload->curl = curl;
 
 	/* make sure these are NULL */
 	FREE(payload->tempfile_name);
@@ -592,6 +584,9 @@ cleanup:
 		unlink(payload->tempfile_name);
 	}
 
+	curl_easy_cleanup(curl);
+	payload->curl = NULL;
+
 	/* restore the old signal handlers */
 	unmask_signal(SIGINT, &orig_sig_int);
 	unmask_signal(SIGPIPE, &orig_sig_pipe);

lib/libalpm/dload.h

@@ -44,6 +44,7 @@ struct dload_payload {
 	int trust_remote_name;
 	int cb_initialized;
 #ifdef HAVE_LIBCURL
+	CURL *curl;
 	CURLcode curlerr;       /* last error produced by curl */
 #endif
 };

lib/libalpm/handle.c

@@ -64,11 +64,6 @@ void _alpm_handle_free(alpm_handle_t *handle)
 		closelog();
 	}
 
-#ifdef HAVE_LIBCURL
-	/* release curl handle */
-	curl_easy_cleanup(handle->curl);
-#endif
-
 #ifdef HAVE_LIBGPGME
 	FREELIST(handle->known_keys);
 #endif

lib/libalpm/handle.h

@@ -59,7 +59,7 @@ struct __alpm_handle_t {
 
 #ifdef HAVE_LIBCURL
 	/* libcurl handle */
-	CURL *curl;             /* reusable curl_easy handle */
+	CURLM *curlm;
 	unsigned short disable_dl_timeout;
 	unsigned int parallel_downloads; /* number of download streams */
 #endif