[pacman-dev] [PATCH 1/2] Add config option to specify amount of concurrent download streams

[Anatol Pomozov]

It includes pacman.conf new 'ConcurrentDownloadStreams' option that
specifies how many concurrent downloads curl starts in parallel.

The value is set to '5' by default. Setting it to '0' removes upper
limit on number of concurrent downloads.

Add alpm_option_set_concurrent_download_streams() ALPM function that
allows to set this config option programmatically.

Signed-off-by: Anatol Pomozov <anatol.pomozov at gmail.com>
---
 doc/pacman.conf.5.asciidoc |  5 +++++
 etc/pacman.conf.in         |  1 +
 lib/libalpm/alpm.h         |  1 +
 lib/libalpm/handle.c       | 12 ++++++++++++
 lib/libalpm/handle.h       |  1 +
 src/pacman/conf.c          |  6 ++++++
 src/pacman/conf.h          |  2 ++
 7 files changed, 28 insertions(+)

diff --git a/doc/pacman.conf.5.asciidoc b/doc/pacman.conf.5.asciidoc
index b297e332..fb00ad18 100644
--- a/doc/pacman.conf.5.asciidoc
+++ b/doc/pacman.conf.5.asciidoc
@@ -205,6 +205,11 @@ Options
 	Disable defaults for low speed limit and timeout on downloads. Use this
 	if you have issues downloading files with proxy and/or security gateway.
 
+*ConcurrentDownloadStreams*::
+	Specifies number of concurrent download streams. This value is set to 5
+	by default. Setting this value to 0 removes upper limit of concurrent
+	streams i.e. all files start downloading in parallel.
+
 
 Repository Sections
 -------------------
diff --git a/etc/pacman.conf.in b/etc/pacman.conf.in
index 7446944f..0a857ef2 100644
--- a/etc/pacman.conf.in
+++ b/etc/pacman.conf.in
@@ -34,6 +34,7 @@ Architecture = auto
 #TotalDownload
 CheckSpace
 #VerbosePkgLists
+#ConcurrentDownloadStreams = 5
 
 # PGP signature checking
 #SigLevel = Optional
diff --git a/lib/libalpm/alpm.h b/lib/libalpm/alpm.h
index c2a069ad..1e488847 100644
--- a/lib/libalpm/alpm.h
+++ b/lib/libalpm/alpm.h
@@ -902,6 +902,7 @@ int alpm_option_get_remote_file_siglevel(alpm_handle_t *handle);
 int alpm_option_set_remote_file_siglevel(alpm_handle_t *handle, int level);
 
 int alpm_option_set_disable_dl_timeout(alpm_handle_t *handle, unsigned short disable_dl_timeout);
+int alpm_option_set_concurrent_download_streams(alpm_handle_t *handle, unsigned int streams_num);
 
 /** @} */
 
diff --git a/lib/libalpm/handle.c b/lib/libalpm/handle.c
index fc7c1faf..a74086d9 100644
--- a/lib/libalpm/handle.c
+++ b/lib/libalpm/handle.c
@@ -856,3 +856,15 @@ int SYMEXPORT alpm_option_set_disable_dl_timeout(alpm_handle_t *handle,
 #endif
 	return 0;
 }
+
+int SYMEXPORT alpm_option_set_concurrent_download_streams(alpm_handle_t *handle,
+		unsigned int streams_num)
+{
+	CHECK_HANDLE(handle, return -1);
+#ifdef HAVE_LIBCURL
+	handle->concurrent_download_streams = streams_num;
+#else
+	(void)streams_num; /* silence unused variable warnings */
+#endif
+	return 0;
+}
\ No newline at end of file
diff --git a/lib/libalpm/handle.h b/lib/libalpm/handle.h
index c343f6e0..d6fe435c 100644
--- a/lib/libalpm/handle.h
+++ b/lib/libalpm/handle.h
@@ -61,6 +61,7 @@ struct __alpm_handle_t {
 	/* libcurl handle */
 	CURL *curl;             /* reusable curl_easy handle */
 	unsigned short disable_dl_timeout;
+	unsigned int concurrent_download_streams; /* Number of parallel downloads, 0 - no limit */
 #endif
 
 #ifdef HAVE_LIBGPGME
diff --git a/src/pacman/conf.c b/src/pacman/conf.c
index f9de386f..1b224eb6 100644
--- a/src/pacman/conf.c
+++ b/src/pacman/conf.c
@@ -110,6 +110,8 @@ config_t *config_new(void)
 		newconfig->localfilesiglevel = ALPM_SIG_USE_DEFAULT;
 		newconfig->remotefilesiglevel = ALPM_SIG_USE_DEFAULT;
 	}
+	/* By default use 5 concurrent download streams */
+	newconfig->concurrent_download_streams = 5;
 
 	newconfig->colstr.colon   = ":: ";
 	newconfig->colstr.title   = "";
@@ -677,6 +679,9 @@ static int _parse_options(const char *key, char *value,
 				return 1;
 			}
 			FREELIST(values);
+		} else if(strcmp(key, "ConcurrentDownloadStreams") == 0) {
+			/* TODO: what is the best way to handle int conversion errors? */
+			config->concurrent_download_streams = atoi(value);
 		} else {
 			pm_printf(ALPM_LOG_WARNING,
 					_("config file %s, line %d: directive '%s' in section '%s' not recognized.\n"),
@@ -845,6 +850,7 @@ static int setup_libalpm(void)
 	alpm_option_set_noextracts(handle, config->noextract);
 
 	alpm_option_set_disable_dl_timeout(handle, config->disable_dl_timeout);
+	alpm_option_set_concurrent_download_streams(handle, config->concurrent_download_streams);
 
 	for(i = config->assumeinstalled; i; i = i->next) {
 		char *entry = i->data;
diff --git a/src/pacman/conf.h b/src/pacman/conf.h
index d954e637..33773efd 100644
--- a/src/pacman/conf.h
+++ b/src/pacman/conf.h
@@ -115,6 +115,8 @@ typedef struct __config_t {
 	/* When downloading, display the amount downloaded, rate, ETA, and percent
 	 * downloaded of the total download list */
 	unsigned short totaldownload;
+	/* Number of concurrent download streams, 0 - no limit */
+	unsigned int concurrent_download_streams;
 	/* select -Sc behavior */
 	unsigned short cleanmethod;
 	alpm_list_t *holdpkg;
-- 
2.25.1