archpkg: support provides

README.rst

@@ -438,7 +438,10 @@ archpkg
   Name of the Arch Linux package.
 
 strip-release
-  Strip the release part.
+  Strip the release part, only return part before ``-``.
+
+provided
+  Instead of the package version, return the version this package provides. Its value is what the package provides, and ``strip-release`` takes effect too. This is best used with libraries.
 
 Check Debian Linux official packages
 ------------------------------------

nvchecker/source/archpkg.py

@@ -14,6 +14,8 @@ get_cacheable_conf = conf_cacheable_with_name('archpkg')
 async def get_version(name, conf, **kwargs):
   pkg = conf.get('archpkg') or name
   strip_release = conf.getboolean('strip-release', False)
+  provided = conf.get('provided')
+
   async with session.get(URL, params={"name": pkg}) as res:
     data = await res.json()
 
@@ -22,7 +24,13 @@ async def get_version(name, conf, **kwargs):
     return
 
   r = [r for r in data['results'] if r['repo'] != 'testing'][0]
-  if strip_release:
+
+  if provided:
+    provides = dict(x.split('=', 1) for x in r['provides'])
+    version = provides.get(provided, None)
+    if strip_release:
+      version = version.split('-', 1)[0]
+  elif strip_release:
     version = r['pkgver']
   else:
     version = r['pkgver'] + '-' + r['pkgrel']

tests/test_archpkg.py

@@ -12,3 +12,19 @@ async def test_archpkg(get_version):
 @flaky
 async def test_archpkg_strip_release(get_version):
     assert await get_version("ipw2100-fw", {"archpkg": None, "strip-release": 1}) == "1.3"
+
+@flaky
+async def test_archpkg_provided(get_version):
+    assert await get_version("jsoncpp", {
+        "archpkg": None,
+        "provided": "libjsoncpp.so",
+    }) == "21-64"
+
+@flaky
+async def test_archpkg_provided_strip(get_version):
+    assert await get_version("jsoncpp", {
+        "archpkg": None,
+        "provided": "libjsoncpp.so",
+        "strip-release": True,
+    }) == "21"
+