sdl: use versioned library, cleanup ffi/util helpers

ffi/SDL2_0.lua

@@ -20,13 +20,7 @@ require("ffi/linux_input_h")
 
 -----------------------------------------------------------------
 
-local SDL = util.ffiLoadCandidates{
-    "SDL2",
-    -- this unfortunately needs to be written in full due to the . in the name
-    "libSDL2-2.0.so",
-    "libSDL2-2.0.so.0",
-    util.KO_DYLD_PREFIX .. "/lib/libSDL2.dylib",
-}
+local SDL = util.loadSDL2()
 
 -- Some features (like SDL_GameControllerRumble) may require a minimum version
 -- of SDL. These helper functions allow us to prevent any issues with calling

ffi/input.lua

@@ -1,9 +1,7 @@
 local util = require("ffi/util")
 
-if util.isSDL() then
-    if util.haveSDL2() then
-        return require("ffi/input_SDL2_0")
-    end
+if util.haveSDL2() then
+    return require("ffi/input_SDL2_0")
 elseif util.isAndroid() then
     return require("ffi/input_android")
 elseif util.isPocketbook() then

ffi/util.lua

@@ -646,17 +646,14 @@ end
 
 function util.ffiLoadCandidates(candidates)
     local lib_loaded, lib
-
     for _, candidate in ipairs(candidates) do
         lib_loaded, lib = pcall(ffi.load, candidate)
-
         if lib_loaded then
             return lib
         end
     end
-
     -- we failed, lib is the error message
-    return lib_loaded, lib
+    return false, lib
 end
 
 local isAndroid = nil
@@ -673,40 +670,37 @@ function util.isPocketbook()
     return lfs.attributes("/ebrmain/pocketbook")
 end
 
-local haveSDL2 = nil
---- Returns true if SDL2
-function util.haveSDL2()
-    local err
-
-    if haveSDL2 == nil then
-        local candidates
+local libSDL2 = nil
+--- Returns SDL2 library
+function util.loadSDL2()
+    if libSDL2 == nil then
+        local candidates, err
         if ffi.os == "OSX" then
-            candidates = {"libs/libSDL2.dylib", "SDL2", util.KO_DYLD_PREFIX .. "/lib/libSDL2.dylib"}
+            candidates = {"libs/libSDL2-2.0.dylib", util.KO_DYLD_PREFIX .. "/lib/libSDL2-2.0.0.dylib",  "SDL2"}
         else
-            candidates = {"SDL2", "libSDL2-2.0.so", "libSDL2-2.0.so.0"}
+            candidates = {"libs/libSDL2-2.0.so.0", "libSDL2-2.0.so.0", "SDL2"}
+        end
+        libSDL2, err = util.ffiLoadCandidates(candidates)
+        if not libSDL2 then
+            print("SDL2 not loaded:", libSDL2)
         end
-        haveSDL2, err = util.ffiLoadCandidates(candidates)
-    end
-    if not haveSDL2 then
-        print("SDL2 not loaded:", err)
     end
-
-    return haveSDL2
+    return libSDL2 or nil
 end
 
-local isSDL = nil
---- Returns true if SDL
-function util.isSDL()
-    if isSDL == nil then
-        isSDL = util.haveSDL2()
+local haveSDL2 = nil
+--- Returns true if SDL2 is available
+function util.haveSDL2()
+    if haveSDL2 == nil then
+        haveSDL2 = util.loadSDL2() and true or false
     end
-    return isSDL
+    return haveSDL2
 end
 
 --- Silence the SDL checks (solely for front's frontend/device.lua usage!)
 function util.noSDL()
     haveSDL2 = false
-    isSDL = false
+    libSDL2 = false
 end
 
 --- Division with integer result.

thirdparty/sdl2/CMakeLists.txt

@@ -2,8 +2,6 @@ list(APPEND PATCH_FILES
     # Remove workarounds for standalone applications and add
     # a couple of actions to be used from the osx main menu.
     cocoa.patch
-    # FIXME: koreader should really be using `libSDL2-2.0.so.0` instead.
-    no_library_versioning.patch
 )
 
 list(APPEND CMAKE_ARGS
@@ -21,7 +19,7 @@ list(APPEND BUILD_CMD COMMAND ninja)
 
 list(APPEND INSTALL_CMD COMMAND ${CMAKE_COMMAND} --install .)
 
-append_shared_lib_install_commands(INSTALL_CMD SDL2)
+append_shared_lib_install_commands(INSTALL_CMD SDL2-2.0 VERSION 0)
 
 external_project(
     DOWNLOAD URL a344eb827a03045c9b399e99af4af13d