private static string[] GetArguments(GhostscriptSettings settings)
{
// Flatten Ghostscript engine settings into string array
// - first argument ignore (argv[0])
// - input path as last argument
string[] arguments;
List <string> argumentItems = new List <string> {
string.Empty
};
foreach (string key in settings.AllKeys)
{
string[] values = settings.GetValues(key);
if (values == null)
{
// No value
argumentItems.Add(key);
}
else
{
IEnumerable <string> items = values.Select(value => string.Concat(key, value));
argumentItems.AddRange(items);
}
}
arguments = argumentItems.ToArray();
return(arguments);
}
public string Execute(GhostscriptSettings settings)
{
if (settings == null)
{
throw new ArgumentNullException("settings");
}
// Flatten settings into Ghostscript arguments
string[] arguments = GetArguments(settings);
// Use callback handlers to capture stdout and stderr.
// NOTE: Delegates do not need to be pinned.
StringBuilder outputBuilder = new StringBuilder();
StringBuilder errorBuilder = new StringBuilder();
GhostscriptMessageEventHandler outputHandler = (i, s, l) => HandleOutputMessage(outputBuilder, s, l);
GhostscriptMessageEventHandler errorHandler = (i, s, l) => HandleOutputMessage(errorBuilder, s, l);
GhostscriptMessageEventHandler inputHandler = (i, s, l) => l;
// NOTE: Ghostscript supports only one instance per process
int result;
lock (_syncObject)
{
// Create a new instance of Ghostscript. This instance is passed to most other gsapi functions.
// The caller_handle will be provided to callback functions.
IntPtr instance;
GhostscriptNativeMethods.NewInstance(out instance, IntPtr.Zero);
// Set the callback functions for stdio.
GhostscriptNativeMethods.SetMessageHandlers(instance, inputHandler, outputHandler, errorHandler);
// Initialise the interpreter.
// This calls gs_main_init_with_args() in imainarg.c. See below for return codes.
// The arguments are the same as the "C" main function: argv[0] is ignored and the user supplied arguments are
// argv[1] to argv[argc-1].
result = GhostscriptNativeMethods.InitializeWithArguments(instance, arguments.Length, arguments);
// Exit the interpreter.
// This must be called on shutdown if gsapi_init_with_args() has been called, and just before gsapi_delete_instance().
GhostscriptNativeMethods.Exit(instance);
// Destroy an instance of Ghostscript.
// Before you call this, Ghostscript must have finished.
// If Ghostscript has been initialised, you must call gsapi_exit before gsapi_delete_instance.
GhostscriptNativeMethods.DeleteInstance(instance);
}
// Check for errors. Zero and e_Quit(-101) are not errors.
string output = outputBuilder.ToString();
if (result != 0 && result != -101)
{
// Use error as message if output is empty
string error = errorBuilder.ToString();
if (string.IsNullOrEmpty(output))
{
output = error;
}
GhostscriptException exception = new GhostscriptException(output);
exception.Data["args"] = arguments;
exception.Data["stderr"] = error;
throw exception;
}
// Return the output message
return(output);
}