alien.libraries.finder: linux code path for find-library

/sbin/ldconfig -p is used to figure out what the correct lib name
is. It is the same method as used in python ctypes.

basis/alien/libraries/finder/finder.factor

@@ -2,16 +2,23 @@ USING:
     alien.libraries
     arrays
     assocs
+    combinators
     formatting
-    io.pathnames
+    io io.encodings.utf8 io.launcher io.pathnames
     kernel
     sequences
+    splitting
     system ;
 IN: alien.libraries.finder
 
+! Util
+: vsprintf1 ( obj fmt -- str )
+    [ 1array ] dip vsprintf ;
+
 CONSTANT: name-formats {
     { windows { "lib%s.dll" "%s.dll" } }
-    { unix { "lib%s.so.0" } }
+    { linux { "lib%s.so" } }
+    { unix { "lib%s.so" } }
     { macosx { "lib%s.0.dylib" } }
 }
 
@@ -24,15 +31,36 @@ CONSTANT: search-paths {
     { macosx { "" } }
 }
 
-: vsprintf1 ( obj fmt -- str )
-    [ 1array ] dip vsprintf ;
-
 : path-formats ( -- path-formats )
     search-paths name-formats [ os of ] bi@
     [ append-path ] cartesian-map concat ;
 
+! Find lib using ldconfig
+CONSTANT: mach-map {
+    { ppc.64 "libc6,64bit" }
+    { x86.32 "libc6,x86-32" }
+    { x86.64 "libc6,x86-64" }
+}
+
+: ldconfig-cache ( -- seq )
+    "/sbin/ldconfig -p" utf8 [ lines ] with-process-reader rest
+    [ "=>" "" replace "\t " split harvest ] map ;
+
+: ldconfig-filter ( -- str )
+    mach-map cpu of dup "libc6" ? "(" ")" surround ;
+
+: ldconfig-matches? ( lib this-lib this-arch -- ? )
+    [ start 0 = ] [ ldconfig-filter = ] bi* and ;
+
+: ldconfig-find-soname ( lib -- seq )
+    name-formats os of first vsprintf1
+    ldconfig-cache [ first2 ldconfig-matches? ] with filter [ first ] map ;
+
 : candidate-paths ( name -- paths )
-    path-formats [ vsprintf1 ] with map ;
+    {
+        { [ os windows? ] [ path-formats [ vsprintf1 ] with map ] }
+        { [ os linux? ] [ ldconfig-find-soname ] }
+    } cond ;
 
 : find-library ( name -- path/f )
     candidate-paths [ dlopen dll-valid? ] map-find nip ;