OOJSScript.m

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/*
 
OOJSScript.m
 
JavaScript support for Oolite
Copyright (C) 2007-2013 David Taylor and Jens Ayton.
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
 
*/
 
#ifndef OO_CACHE_JS_SCRIPTS
#define OO_CACHE_JS_SCRIPTS     1
#endif
 
 
#import "OOJSScript.h"
#import "OOJavaScriptEngine.h"
#import "OOJSEngineTimeManagement.h"
 
#import "OOLogging.h"
#import "OOConstToString.h"
#import "Entity.h"
#import "NSStringOOExtensions.h"
#import "EntityOOJavaScriptExtensions.h"
#import "OOConstToJSString.h"
#import "OOManifestProperties.h"
#import "OOCollectionExtractors.h"
#import "OOPListParsing.h"
#import "OODebugStandards.h"
 
#if OO_CACHE_JS_SCRIPTS
#include <jsxdrapi.h>
#import "OOCacheManager.h"
#endif
 
 
typedef struct RunningStack RunningStack;
struct RunningStack
{
    RunningStack        *back;
    OOJSScript          *current;
};
 
 
static JSObject         *sScriptPrototype;
static RunningStack     *sRunningStack = NULL;
 
 
static void AddStackToArrayReversed(NSMutableArray *array, RunningStack *stack);
 
static JSScript *LoadScriptWithName(JSContext *context, NSString *path, JSObject *object, JSObject **outScriptObject, NSString **outErrorMessage);
 
#if OO_CACHE_JS_SCRIPTS
static NSData *CompiledScriptData(JSContext *context, JSScript *script);
static JSScript *ScriptWithCompiledData(JSContext *context, NSData *data);
#endif
 
static NSString *StrippedName(NSString *string);
 
 
static JSBool ScriptAddProperty(JSContext *context, JSObject *this, jsid propID, jsval *value);
 
 
static JSClass sScriptClass =
{
    "Script",
    JSCLASS_HAS_PRIVATE,
    
    ScriptAddProperty,
    JS_PropertyStub,
    JS_PropertyStub,
    JS_StrictPropertyStub,
    JS_EnumerateStub,
    JS_ResolveStub,
    JS_ConvertStub,
    OOJSObjectWrapperFinalize
};
 
 
static JSFunctionSpec sScriptMethods[] =
{
    // JS name                  Function                    min args
    { "toString",               OOJSObjectWrapperToString,  0, },
    { 0 }
};
 
 
@interface OOJSScript (OOPrivate)
 
- (NSString *)scriptNameFromPath:(NSString *)path;
- (NSDictionary *)defaultPropertiesFromPath:(NSString *)path;
 
@end
 
 
@implementation OOJSScript
 
+ (id) scriptWithPath:(NSString *)path properties:(NSDictionary *)properties
{
    return [[[self alloc] initWithPath:path properties:properties] autorelease];
}
 
 
- (id) initWithPath:(NSString *)path properties:(NSDictionary *)properties
{
    JSContext               *context = NULL;
    NSString                *problem = nil;     // Acts as error flag.
    JSScript                *script = NULL;
    JSObject                *scriptObject = NULL;
    jsval                   returnValue = JSVAL_VOID;
    NSEnumerator            *keyEnum = nil;
    NSString                *key = nil;
    id                      property = nil;
    
    self = [super init];
    if (self == nil) problem = @"allocation failure";
    else
    {
        context = OOJSAcquireContext();
        
        if (JS_IsExceptionPending(context))
        {
            JS_ClearPendingException(context);
            OOLogERR(@"script.javaScript.load.waitingException", @"Prior to loading script %@, there was a pending JavaScript exception, which has been cleared. This is an internal error, please report it.", path);
        }
        
        // Set up JS object
        if (!problem)
        {
            _jsSelf = JS_NewObject(context, &sScriptClass, sScriptPrototype, NULL);
            if (_jsSelf == NULL) problem = @"allocation failure";
        }
        
        if (!problem && !OOJSAddGCObjectRoot(context, &_jsSelf, "Script object"))
        {
            problem = @"could not add JavaScript root object";
        }
        
        if (!problem && !OOJSAddGCObjectRoot(context, &scriptObject, "Script GC holder"))
        {
            problem = @"could not add JavaScript root object";
        }
        
        if (!problem)
        {
            if (!JS_SetPrivate(context, _jsSelf, OOConsumeReference([self weakRetain])))
            {
                problem = @"could not set private backreference";
            }
        }
        
        // Push self on stack of running scripts.
        RunningStack stackElement =
        {
            .back = sRunningStack,
            .current = self
        };
        sRunningStack = &stackElement;
        
        filePath = [path retain];
        
        if (!problem)
        {
            OOLog(@"script.javaScript.willLoad", @"About to load JavaScript %@", path);
            script = LoadScriptWithName(context, path, _jsSelf, &scriptObject, &problem);
        }
        OOLogIndentIf(@"script.javaScript.willLoad");
        
        // Set default properties from manifest.plist
        NSDictionary *defaultProperties = [self defaultPropertiesFromPath:path];
        for (keyEnum = [defaultProperties keyEnumerator]; (key = [keyEnum nextObject]); )
        {
            if ([key isKindOfClass:[NSString class]])
            {
                property = [defaultProperties objectForKey:key];
                if ([key isEqualToString:kLocalManifestProperty])
                {
                    // this must not be editable
                    [self defineProperty:property named:key];
                }
                else
                {
                    // can be overwritten by script itself
                    [self setProperty:property named:key];
                }
            }
        }
 
        // Set properties. (read-only)
        if (!problem && properties != nil)
        {
            for (keyEnum = [properties keyEnumerator]; (key = [keyEnum nextObject]); )
            {
                if ([key isKindOfClass:[NSString class]])
                {
                    property = [properties objectForKey:key];
                    [self defineProperty:property named:key];
                }
            }
        }
        
        /*  Set initial name (in case of script error during initial run).
            The "name" ivar is not set here, so the property can be fetched from JS
            if we fail during setup. However, the "name" ivar is set later so that
            the script object can't be renamed after the initial run. This could
            probably also be achieved by fiddling with JS property attributes.
        */
        jsid nameID = OOJSID("name");
        [self setProperty:[self scriptNameFromPath:path] withID:nameID inContext:context];
        
        // Run the script (allowing it to set up the properties we need, as well as setting up those event handlers)
        if (!problem)
        {
            OOJSStartTimeLimiterWithTimeLimit(kOOJSLongTimeLimit);
            if (!JS_ExecuteScript(context, _jsSelf, script, &returnValue))
            {
                problem = @"could not run script";
            }
            OOJSStopTimeLimiter();
            
            // We don't need the script any more - the event handlers hang around as long as the JS object exists.
            JS_DestroyScript(context, script);
        }
        
        JS_RemoveObjectRoot(context, &scriptObject);
        
        sRunningStack = stackElement.back;
        
        if (!problem)
        {
            // Get display attributes from script
            DESTROY(name);
            name = [StrippedName([[self propertyWithID:nameID inContext:context] description]) copy];
            if (name == nil)
            {
                name = [[self scriptNameFromPath:path] retain];
                [self setProperty:name withID:nameID inContext:context];
            }
            
            version = [[[self propertyWithID:OOJSID("version") inContext:context] description] copy];
            description = [[[self propertyWithID:OOJSID("description") inContext:context] description] copy];
            
            OOLog(@"script.javaScript.load.success", @"Loaded JavaScript: %@ -- %@", [self displayName], description ? description : (NSString *)@"(no description)");
        }
        
        OOLogOutdentIf(@"script.javaScript.willLoad");
        
        DESTROY(filePath);  // Only used for error reporting during startup.
    }
    
    if (problem)
    {
        OOLog(@"script.javaScript.load.failed", @"***** Error loading JavaScript script %@ -- %@", path, problem);
        JS_ReportPendingException(context);
        DESTROY(self);
    }
    
    OOJSRelinquishContext(context);
    
    if (self != nil)
    {
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(javaScriptEngineWillReset:)
                                                     name:kOOJavaScriptEngineWillResetNotification
                                                   object:[OOJavaScriptEngine sharedEngine]];
    }
    
    return self;
}
 
 
- (void) dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:kOOJavaScriptEngineWillResetNotification
                                                  object:[OOJavaScriptEngine sharedEngine]];
    
    DESTROY(name);
    DESTROY(description);
    DESTROY(version);
    DESTROY(filePath);
    
    if (_jsSelf != NULL)
    {
        JSContext *context = OOJSAcquireContext();
        
        OOJSObjectWrapperFinalize(context, _jsSelf);    // Release weakref to self
        JS_RemoveObjectRoot(context, &_jsSelf);         // Unroot jsSelf
        
        OOJSRelinquishContext(context);
    }
    
    [weakSelf weakRefDrop];
    
    [super dealloc];
}
 
 
- (NSString *) oo_jsClassName
{
    return @"Script";
}
 
 
- (NSString *)descriptionComponents
{
    if (_jsSelf != NULL)  return [super descriptionComponents];
    else  return @"invalid script";
}
 
 
- (void) javaScriptEngineWillReset:(NSNotification *)notification
{
    // All scripts become invalid when the JS engine resets.
    if (_jsSelf != NULL)
    {
        _jsSelf = NULL;
        JSContext *context = OOJSAcquireContext();
        JS_RemoveObjectRoot(context, &_jsSelf);
        OOJSRelinquishContext(context);
    }
}
 
 
+ (OOJSScript *) currentlyRunningScript
{
    if (sRunningStack == NULL)  return NULL;
    return sRunningStack->current;
}
 
 
+ (NSArray *) scriptStack
{
    NSMutableArray          *result = nil;
    
    result = [NSMutableArray array];
    AddStackToArrayReversed(result, sRunningStack);
    return result;
}
 
 
- (id) weakRetain
{
    if (weakSelf == nil)  weakSelf = [OOWeakReference weakRefWithObject:self];
    return [weakSelf retain];
}
 
 
- (void) weakRefDied:(OOWeakReference *)weakRef
{
    if (weakRef == weakSelf)  weakSelf = nil;
}
 
 
- (NSString *) name
{
    if (name == nil)  name = [[self propertyNamed:@"name"] copy];
    if (name == nil)  return [self scriptNameFromPath:filePath];    // Special case for parse errors during load.
    return name;
}
 
 
- (NSString *) scriptDescription
{
    return description;
}
 
 
- (NSString *) version
{
    return version;
}
 
 
- (void)runWithTarget:(Entity *)target
{
    
}
 
 
- (BOOL) callMethod:(jsid)methodID
          inContext:(JSContext *)context
      withArguments:(jsval *)argv count:(intN)argc
             result:(jsval *)outResult
{
    NSParameterAssert(name != NULL && (argv != NULL || argc == 0) && context != NULL && JS_IsInRequest(context));
    if (_jsSelf == NULL)  return NO;
    
    JSObject                *root = NULL;
    BOOL                    OK = NO;
    jsval                   method;
    jsval                   ignoredResult = JSVAL_VOID;
    
    if (outResult == NULL)  outResult = &ignoredResult;
    OOJSAddGCObjectRoot(context, &root, "OOJSScript method root");
    
    if (EXPECT(JS_GetMethodById(context, _jsSelf, methodID, &root, &method) && !JSVAL_IS_VOID(method)))
    {
#ifndef NDEBUG
        if (JS_IsExceptionPending(context))
        {
            OOLog(@"script.internalBug", @"Exception pending on context before calling method in %s, clearing. This is an internal error, please report it.", __PRETTY_FUNCTION__);
            JS_ClearPendingException(context);
        }
        
        OOLog(@"script.javaScript.call", @"Calling [%@].%@()", [self name], OOStringFromJSID(methodID));
        OOLogIndentIf(@"script.javaScript.call");
#endif
        
        // Push self on stack of running scripts.
        RunningStack stackElement =
        {
            .back = sRunningStack,
            .current = self
        };
        sRunningStack = &stackElement;
        
        // Call the method.
        OOJSStartTimeLimiter();
        OK = JS_CallFunctionValue(context, _jsSelf, method, argc, argv, outResult);
        OOJSStopTimeLimiter();
        
        if (JS_IsExceptionPending(context))
        {
            JS_ReportPendingException(context);
            OK = NO;
        }
        
        // Pop running scripts stack
        sRunningStack = stackElement.back;
        
#ifndef NDEBUG
        OOLogOutdentIf(@"script.javaScript.call");
#endif
    }
    
    JS_RemoveObjectRoot(context, &root);
    
    return OK;
}
 
 
- (id) propertyWithID:(jsid)propID inContext:(JSContext *)context
{
    NSParameterAssert(context != NULL && JS_IsInRequest(context));
    if (_jsSelf == NULL)  return nil;
    
    jsval jsValue = JSVAL_VOID;
    if (JS_GetPropertyById(context, _jsSelf, propID, &jsValue))
    {
        return OOJSNativeObjectFromJSValue(context, jsValue);
    }
    return nil;
}
 
 
- (BOOL) setProperty:(id)value withID:(jsid)propID inContext:(JSContext *)context
{
    NSParameterAssert(context != NULL && JS_IsInRequest(context));
    if (_jsSelf == NULL)  return NO;
    
    jsval jsValue = OOJSValueFromNativeObject(context, value);
    return JS_SetPropertyById(context, _jsSelf, propID, &jsValue);
}
 
 
- (BOOL) defineProperty:(id)value withID:(jsid)propID inContext:(JSContext *)context
{
    NSParameterAssert(context != NULL && JS_IsInRequest(context));
    if (_jsSelf == NULL)  return NO;
    
    jsval jsValue = OOJSValueFromNativeObject(context, value);
    return JS_DefinePropertyById(context, _jsSelf, propID, jsValue, NULL, NULL, OOJS_PROP_READONLY);
}
 
 
- (id) propertyNamed:(NSString *)propName
{
    if (propName == nil)  return nil;
    if (_jsSelf == NULL)  return nil;
    
    JSContext *context = OOJSAcquireContext();
    id result = [self propertyWithID:OOJSIDFromString(propName) inContext:context];
    OOJSRelinquishContext(context);
    
    return result;
}
 
 
- (BOOL) setProperty:(id)value named:(NSString *)propName
{
    if (value == nil || propName == nil)  return NO;
    if (_jsSelf == NULL)  return NO;
    
    JSContext *context = OOJSAcquireContext();
    BOOL result = [self setProperty:value withID:OOJSIDFromString(propName) inContext:context];
    OOJSRelinquishContext(context);
    
    return result;
}
 
 
- (BOOL) defineProperty:(id)value named:(NSString *)propName
{
    if (value == nil || propName == nil)  return NO;
    if (_jsSelf == NULL)  return NO;
    
    JSContext *context = OOJSAcquireContext();
    BOOL result = [self defineProperty:value withID:OOJSIDFromString(propName) inContext:context];
    OOJSRelinquishContext(context);
    
    return result;
}
 
 
- (jsval)oo_jsValueInContext:(JSContext *)context
{
    if (_jsSelf == NULL)  return JSVAL_VOID;
    return OBJECT_TO_JSVAL(_jsSelf);
}
 
 
+ (void)pushScript:(OOJSScript *)script
{
    RunningStack            *element = NULL;
    
    element = malloc(sizeof *element);
    if (element == NULL)  exit(EXIT_FAILURE);
    
    element->back = sRunningStack;
    element->current = script;
    sRunningStack = element;
}
 
 
+ (void)popScript:(OOJSScript *)script
{
    RunningStack            *element = NULL;
    
    assert(sRunningStack->current == script);
    
    element = sRunningStack;
    sRunningStack = sRunningStack->back;
    free(element);
}
 
@end
 
 
@implementation OOJSScript (OOPrivate)
 
 
 
/*  Generate default name for script which doesn't set its name property when
    first run.
 
    The generated name is <name>.anon-script, where <name> is selected as
    follows:
    * If path is nil (futureproofing), use the address of the script object.
    * If the file's name is something other than script.*, use the file name.
    * If the containing directory is something other than Config, use the
    containing directory's name.
    * Otherwise, use the containing directory's parent (which will generally
                                                        be an OXP root directory).
    * If either of the two previous steps results in an empty string, fall
    back on the full path.
*/
- (NSString *)scriptNameFromPath:(NSString *)path
{
    NSString        *lastComponent = nil;
    NSString        *truncatedPath = nil;
    NSString        *theName = nil;
    
    if (path == nil) theName = [NSString stringWithFormat:@"%p", self];
    else
    {
        lastComponent = [path lastPathComponent];
        if (![lastComponent hasPrefix:@"script."]) theName = lastComponent;
        else
        {
            truncatedPath = [path stringByDeletingLastPathComponent];
            if (NSOrderedSame == [[truncatedPath lastPathComponent] caseInsensitiveCompare:@"Config"])
            {
                truncatedPath = [truncatedPath stringByDeletingLastPathComponent];
            }
            if (NSOrderedSame == [[truncatedPath pathExtension] caseInsensitiveCompare:@"oxp"])
            {
                truncatedPath = [truncatedPath stringByDeletingPathExtension];
            }
            
            lastComponent = [truncatedPath lastPathComponent];
            theName = lastComponent;
        }
    }
    
    if (0 == [theName length]) theName = path;
    
    return StrippedName([theName stringByAppendingString:@".anon-script"]);
}
 
 
- (NSDictionary *) defaultPropertiesFromPath:(NSString *)path
{
    // remove file name, remove OXP subfolder, add manifest.plist
    NSString *manifestPath = [[[path stringByDeletingLastPathComponent] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"manifest.plist"];
    NSDictionary *manifest = OODictionaryFromFile(manifestPath);
    NSMutableDictionary *properties = [NSMutableDictionary dictionaryWithCapacity:3];
    /* __oolite.tmp.* is allocated for OXPs without manifests. Its
     * values are meaningless and shouldn't be used here */
    if (manifest != nil && ![[manifest oo_stringForKey:kOOManifestIdentifier] hasPrefix:@"__oolite.tmp."])
    {
        if ([manifest objectForKey:kOOManifestVersion] != nil)
        {
            [properties setObject:[manifest oo_stringForKey:kOOManifestVersion] forKey:@"version"];
        }
        if ([manifest objectForKey:kOOManifestIdentifier] != nil)
        {
            // used for system info
            [properties setObject:[manifest oo_stringForKey:kOOManifestIdentifier] forKey:kLocalManifestProperty];
        }
        if ([manifest objectForKey:kOOManifestAuthor] != nil)
        {
            [properties setObject:[manifest oo_stringForKey:kOOManifestAuthor] forKey:@"author"];
        }
        if ([manifest objectForKey:kOOManifestLicense] != nil)
        {
            [properties setObject:[manifest oo_stringForKey:kOOManifestLicense] forKey:@"license"];
        }
    }
    return properties;
}
 
@end
 
 
@implementation OOScript (JavaScriptEvents)
 
- (BOOL) callMethod:(jsid)methodID
          inContext:(JSContext *)context
      withArguments:(jsval *)argv count:(intN)argc
             result:(jsval *)outResult
{
    return NO;
}
 
@end
 
 
void InitOOJSScript(JSContext *context, JSObject *global)
{
    sScriptPrototype = JS_InitClass(context, global, NULL, &sScriptClass, OOJSUnconstructableConstruct, 0, NULL, sScriptMethods, NULL, NULL);
    OOJSRegisterObjectConverter(&sScriptClass, OOJSBasicPrivateObjectConverter);
}
 
 
static JSBool ScriptAddProperty(JSContext *context, JSObject *this, jsid propID, jsval *value)
{
    // Complain about attempts to set the property tickle.
    if (JSID_IS_STRING(propID))
    {
        JSString *propName = JSID_TO_STRING(propID);
        JSBool match;
        if (JS_StringEqualsAscii(context, propName, "tickle", &match) && match)
        {
            OOJSScript *thisScript = OOJSNativeObjectOfClassFromJSObject(context, this, [OOJSScript class]);
            OOJSReportWarning(context, @"Script %@ appears to use the tickle() event handler, which is no longer supported.", [thisScript name]);
        }
    }
    
    return YES;
}
 
 
static void AddStackToArrayReversed(NSMutableArray *array, RunningStack *stack)
{
    if (stack != NULL)
    {
        AddStackToArrayReversed(array, stack->back);
        [array addObject:stack->current];
    }
}
 
 
static JSScript *LoadScriptWithName(JSContext *context, NSString *path, JSObject *object, JSObject **outScriptObject, NSString **outErrorMessage)
{
#if OO_CACHE_JS_SCRIPTS
    OOCacheManager              *cache = nil;
#endif
    NSString                    *fileContents = nil;
    NSData                      *data = nil;
    JSScript                    *script = NULL;
    
    NSCParameterAssert(outScriptObject != NULL && outErrorMessage != NULL);
    *outErrorMessage = nil;
    
#if OO_CACHE_JS_SCRIPTS
    // Look for cached compiled script
    cache = [OOCacheManager sharedCache];
    data = [cache objectForKey:path inCache:@"compiled JavaScript scripts"];
    if (data != nil)
    {
        script = ScriptWithCompiledData(context, data);
    }
#endif
    
    if (script == NULL)
    {
        fileContents = [NSString stringWithContentsOfUnicodeFile:path];
 
        if (fileContents != nil) 
        {
#ifndef NDEBUG
        /* FIXME: this isn't strictly the right test, since strict
         * mode can be enabled with this string within a function
         * definition, but it seems unlikely anyone is actually doing
         * that here. */
        if ([fileContents rangeOfString:@"\"use strict\";"].location == NSNotFound && [fileContents rangeOfString:@"'use strict';"].location == NSNotFound)
        {
            OOStandardsDeprecated([NSString stringWithFormat:@"Script %@ does not \"use strict\";",path]);
            if (OOEnforceStandards())
            {
                // prepend it anyway
                // TODO: some time after 1.82, make this required
                fileContents = [@"\"use strict\";\n" stringByAppendingString:fileContents];
            }
        }
#endif
            data = [fileContents utf16DataWithBOM:NO];
        }
        if (data == nil)  *outErrorMessage = @"could not load file";
        else
        {
            script = JS_CompileUCScript(context, object, [data bytes], [data length] / sizeof(unichar), [path UTF8String], 1);
            if (script != NULL)  *outScriptObject = JS_NewScriptObject(context, script);
            else  *outErrorMessage = @"compilation failed";
        }
        
#if OO_CACHE_JS_SCRIPTS
        if (script != NULL)
        {
            // Write compiled script to cache
            data = CompiledScriptData(context, script);
            [cache setObject:data forKey:path inCache:@"compiled JavaScript scripts"];
        }
#endif
    }
    
    return script;
}
 
 
#if OO_CACHE_JS_SCRIPTS
static NSData *CompiledScriptData(JSContext *context, JSScript *script)
{
    JSXDRState                  *xdr = NULL;
    NSData                      *result = nil;
    uint32                      length;
    void                        *bytes = NULL;
    
    xdr = JS_XDRNewMem(context, JSXDR_ENCODE);
    if (xdr != NULL)
    {
        if (JS_XDRScript(xdr, &script))
        {
            bytes = JS_XDRMemGetData(xdr, &length);
            if (bytes != NULL)
            {
                result = [NSData dataWithBytes:bytes length:length];
            }
        }
        JS_XDRDestroy(xdr);
    }
    
    return result;
}
 
 
static JSScript *ScriptWithCompiledData(JSContext *context, NSData *data)
{
    JSXDRState                  *xdr = NULL;
    JSScript                    *result = NULL;
    
    if (data == nil)  return NULL;
    
    xdr = JS_XDRNewMem(context, JSXDR_DECODE);
    if (xdr != NULL)
    {
        NSUInteger length = [data length];
        if (EXPECT_NOT(length > UINT32_MAX))  return NULL;
        
        JS_XDRMemSetData(xdr, (void *)[data bytes], (uint32_t)length);
        if (!JS_XDRScript(xdr, &result))  result = NULL;
        
        JS_XDRMemSetData(xdr, NULL, 0); // Don't let it be freed by XDRDestroy
        JS_XDRDestroy(xdr);
    }
    
    return result;
}
#endif
 
 
static NSString *StrippedName(NSString *string)
{
    static NSCharacterSet *invalidSet = nil;
    if (invalidSet == nil)  invalidSet = [[NSCharacterSet characterSetWithCharactersInString:@"_ \t\n\r\v"] retain];
    
    return [string stringByTrimmingCharactersInSet:invalidSet];
}