[sugg/BUG?] NCONVERT plugin management: make it fool proof
Posted: Sun Mar 06, 2011 1:50 pm
(as started in messy thread: http://newsgroup.xnview.com/viewtopic.php?t=21685)
Problem: plugin management in NC is not very user friendly and fool-proof (+ possibly even buggy).
- Plugins are not accepted in same directory as NC
- It says "Error: Don't know how to read this picture" ... but better message would be "This format needs the plugin" (name) or "Plugin" (name) "failed" (additionally at startup: "Plugin" (name) "DLL load/init failed" or "NOT found")
- Loads same plugin 2 times (5.85: before and after opening the input file) (or even more is possible?) ??? Tries even wrong plugins (5.80) ...
- Very hard to debug, verbose option says nothing about attempts to find or use plugins
So I invented following (pseudo-code) to fix this (run at NC start, before opening any input files):
Later, when processing files, return (even if not verbose):
- "Error: Don't know how to read this picture" only if no plugin exists to handle it
- "This format needs the plugin" (name) if plugin could help, but (PluginMoHaArray (PluginIndex) == 0)
- "Plugin" (name) "failed" if plugin returned failure or GetProcAddress return "NOT found" for needed function
Example output:
---------------------------
Problem: plugin management in NC is not very user friendly and fool-proof (+ possibly even buggy).
- Plugins are not accepted in same directory as NC
- It says "Error: Don't know how to read this picture" ... but better message would be "This format needs the plugin" (name) or "Plugin" (name) "failed" (additionally at startup: "Plugin" (name) "DLL load/init failed" or "NOT found")
- Loads same plugin 2 times (5.85: before and after opening the input file) (or even more is possible?) ??? Tries even wrong plugins (5.80) ...
- Very hard to debug, verbose option says nothing about attempts to find or use plugins
So I invented following (pseudo-code) to fix this (run at NC start, before opening any input files):
Code: Select all
X0 = GetFileAttributes ("PLUGINS")
IF (X0 says "exists and is a DIRECTORY") THEN
PluginSearchPath="PLUGINS\" // The old known behavior
ELSE
PluginSearchPath="" // Look in the same directory
ENDIF
PluginIndex := 0
DO
IF (PluginIndex says "no more plugins") THEN EXIT
PluginName = ArrayOfPluginNames (PluginIndex)
PluginMoHaArray (PluginIndex) := 0 // NOT available
S1 = PluginSearchPath + PluginName + ".DLL"
IF ("verbose") THEN PRINT "Plugin: " + S1 + " ... "
X2 = GetFileAttributes (S1)
IF (X2 says "exists and is a file") THEN
X3 = LoadLibrary (S1)
IF (X3 == "success") THEN
PluginMoHaArray (PluginIndex) := X3 // Save Module Handle
IF ("verbose") THEN PRINT "Loaded OK"
ELSE
IF ("verbose") THEN PRINT "DLL load/init failed"
// Most ^^^ likely some stupid 4th party DLL like
// MSVCxxxx was not found or has wrong version :-(
ENDIF (X3 == "success") // LoadLibrary result
ELSE // plugin file existence
IF ("verbose") THEN PRINT "NOT found"
ENDIF // plugin file existence
INC (PluginIndex)
IF ("verbose") THEN PRINT (EOL)
LOOP
- "Error: Don't know how to read this picture" only if no plugin exists to handle it
- "This format needs the plugin" (name) if plugin could help, but (PluginMoHaArray (PluginIndex) == 0)
- "Plugin" (name) "failed" if plugin returned failure or GetProcAddress return "NOT found" for needed function
Example output:
---------------------------
orPlugin: "webp.dll" ... Loaded OK
Plugin: "CADImage.DLL" ... NOT found
Plugin: "CS_DXF.DLL" ... NOT found
Plugin: "lwf.dll" ... NOT found
Plugin: "ldf.dll" ... DLL load/init failed
---------------------------Plugin: "PLUGINS\webp.dll" ... Loaded OK
Plugin: "PLUGINS\CADImage.DLL" ... Loaded OK
Plugin: "PLUGINS\CS_DXF.DLL" ... Loaded OK
Plugin: "PLUGINS\lwf.dll" ... Loaded OK
Plugin: "PLUGINS\ldf.dll" ... Loaded OK
orThis format needs the plugin "WEBP.DLL"
---------------------------Plugin "WEBP.DLL" failed
