unix: factor out reusable sysinfo memory lookup

On Linux we use `sysinfo(2)` to look up available memory.
Factor out a dedicated source file to make this implementation
available for use on other platforms that support it.

PR-URL: https://github.com/libuv/libuv/pull/1312
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

Makefile.am

@@ -377,7 +377,8 @@ libuv_la_SOURCES += src/unix/linux-core.c \
                     src/unix/linux-inotify.c \
                     src/unix/linux-syscalls.c \
                     src/unix/linux-syscalls.h \
-                    src/unix/proctitle.c
+                    src/unix/proctitle.c \
+                    src/unix/sysinfo-memory.c
 test_run_tests_LDFLAGS += -lutil
 endif
 

src/unix/linux-core.c

@@ -503,24 +503,6 @@ int uv_exepath(char* buffer, size_t* size) {
 }
 
 
-uint64_t uv_get_free_memory(void) {
-  struct sysinfo info;
-
-  if (sysinfo(&info) == 0)
-    return (uint64_t) info.freeram * info.mem_unit;
-  return 0;
-}
-
-
-uint64_t uv_get_total_memory(void) {
-  struct sysinfo info;
-
-  if (sysinfo(&info) == 0)
-    return (uint64_t) info.totalram * info.mem_unit;
-  return 0;
-}
-
-
 int uv_resident_set_memory(size_t* rss) {
   char buf[1024];
   const char* s;

src/unix/sysinfo-memory.c

@@ -0,0 +1,42 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "internal.h"
+
+#include <stdint.h>
+#include <sys/sysinfo.h>
+
+uint64_t uv_get_free_memory(void) {
+  struct sysinfo info;
+
+  if (sysinfo(&info) == 0)
+    return (uint64_t) info.freeram * info.mem_unit;
+  return 0;
+}
+
+uint64_t uv_get_total_memory(void) {
+  struct sysinfo info;
+
+  if (sysinfo(&info) == 0)
+    return (uint64_t) info.totalram * info.mem_unit;
+  return 0;
+}

uv.gyp

@@ -237,6 +237,7 @@
             'src/unix/linux-inotify.c',
             'src/unix/linux-syscalls.c',
             'src/unix/linux-syscalls.h',
+            'src/unix/sysinfo-memory.c',
           ],
           'link_settings': {
             'libraries': [ '-ldl', '-lrt' ],
@@ -251,6 +252,7 @@
             'src/unix/pthread-fixes.c',
             'src/unix/android-ifaddrs.c',
             'src/unix/pthread-barrier.c'
+            'src/unix/sysinfo-memory.c',
           ],
           'link_settings': {
             'libraries': [ '-ldl' ],