/*

Copyright (c) 2011 Andrew Goodale. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are

permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of

conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list

of conditions and the following disclaimer in the documentation and/or other materials

provided with the distribution.

THIS SOFTWARE IS PROVIDED BY ANDREW GOODALE "AS IS" AND ANY EXPRESS OR IMPLIED

WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR

CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those of the

authors and should not be interpreted as representing official policies, either expressed

or implied, of Andrew Goodale.

*/

#import "GAScriptEngine.h"

#import "GAScriptObject.h"

#import "GAScriptBlockObject.h"

#import "NSObject+GAJavaScript.h"

@interface GAScriptEngine ()

/**

* Loads the GAJavaScript runtime into this webview. This method should be called in the

* UIWebViewDelegate webViewDidFinishLoad: method.

*/

- (void)loadScriptRuntime;

- (BOOL)scriptRuntimeIsLoaded;

- (void)makeLotsaCalls;

- (void)callReceiversForSelector:(SEL)theSelector withArguments:(NSArray *)arguments;

@end

#pragma mark -

@implementation GAScriptEngine

@synthesize webView = m_webView;

@synthesize receivers = m_receivers;

- (id)initWithWebView:(UIWebView *)webView

{

if ((self = [super init]))

{

m_webView = [webView retain];

m_delegate = [webView delegate];

m_webView.delegate = self;

m_receivers = [[NSMutableArray alloc] initWithCapacity:4];

}

return self;

}

- (id)initWithSuperview:(UIView *)superview delegate:(id<UIWebViewDelegate>)delegate

{

UIWebView* webView = [[UIWebView alloc] initWithFrame:CGRectMake(0.0, 0.0, 0.0, 0.0)];

webView.delegate = delegate;

webView.hidden = YES;

// Setting these will hopefully reduce some memory and CPU consumption in the webview

//

webView.userInteractionEnabled = NO;

webView.dataDetectorTypes = UIDataDetectorTypeNone;

[superview addSubview:webView];

[webView release];

return [self initWithWebView:webView];

}

- (void)dealloc

{

[m_webView release];

[m_document release];

[m_window release];

[m_receivers release];

[super dealloc];

}

- (GAScriptObject *)documentObject

{

if (m_document == nil)

m_document = [[GAScriptObject alloc] initForReference:@"document" view:m_webView];

return m_document;

}

- (GAScriptObject *)windowObject

{

if (m_window == nil)

m_window = [[GAScriptObject alloc] initForReference:@"window" view:m_webView];

return m_window;

}

- (GAScriptObject *)newScriptObject

{

NSString* objRef = [m_webView stringByEvaluatingJavaScriptFromString:@"GAJavaScript.makeReference(new Object())"];

GAScriptObject* jsObject = [[GAScriptObject alloc] initForReference:objRef view:m_webView];

return jsObject;

}

- (GAScriptObject *)newScriptObject:(NSString *)constructorName

{

NSString* js = [NSString stringWithFormat:@"GAJavaScript.makeReference(new %@())", constructorName];

NSString* objRef = [m_webView stringByEvaluatingJavaScriptFromString:js];

GAScriptObject* jsObject = [[GAScriptObject alloc] initForReference:objRef view:m_webView];

return jsObject;

}

- (GAScriptObject *)scriptObjectWithReference:(NSString *)reference

{

GAScriptObject* jsObject = [[GAScriptObject alloc] initForReference:reference view:m_webView];

return [jsObject autorelease];

}

/**

* Call functions at global (window) scope.

*/

- (id)callFunction:(NSString *)functionName

{

return [self.windowObject callFunction:functionName];

}

- (id)callFunction:(NSString *)functionName withObject:(id)argument

{

return [self.windowObject callFunction:functionName withObject:argument];

}

#pragma mark Private

- (void)loadScriptRuntime

{

if ([self scriptRuntimeIsLoaded]) // Don't re-evaluate the runtime javascript, because it will destroy all existing object references.

return;

NSString* scriptFile = [[NSBundle mainBundle] pathForResource:@"ga-js-runtime" ofType:@"js"];

NSAssert(scriptFile != nil, @"The main bundle is missing the file 'ga-js-runtime.js'!");

NSString* scriptData = [NSString stringWithContentsOfFile:scriptFile

encoding:NSUTF8StringEncoding

error:nil];

NSAssert(scriptData != nil, @"The javascript code in ga-js-runtime.js could not be read");

[m_webView stringByEvaluatingJavaScriptFromString:scriptData];

}

- (BOOL)scriptRuntimeIsLoaded

{

return [[m_webView stringByEvaluatingJavaScriptFromString:@"typeof GAJavaScript"] isEqualToString:@"object"];

}

- (void)makeLotsaCalls

{

id calls = [self scriptObjectWithReference:@"GAJavaScript.calls"];

NSNumber* numCalls = [calls valueForKey:@"length"];

calls = [calls callFunction:@"splice"

withArguments:[NSArray arrayWithObjects:[NSNumber numberWithInt:0], numCalls, nil]];

for (NSInteger i = 0; i < [calls count]; ++i)

{

id call = [calls objectAtIndex:i];

NSString* selName = [call valueForKey:@"sel"];

NSNumber* invName = [call valueForKey:@"inv"];

NSArray* arguments = [call valueForKey:@"args"];

if (selName != nil && [selName isKindOfClass:[NSString class]])

{

SEL theSelector = NSSelectorFromString(selName);

[self callReceiversForSelector:theSelector withArguments:arguments];

}

else if (invName != nil && [invName isKindOfClass:[NSNumber class]])

{

// Will be the address of a block

//

GAScriptBlock theBlock = (GAScriptBlock) [invName unsignedLongLongValue];

if (theBlock)

theBlock(arguments);

}

}

}

- (void)callReceiversForSelector:(SEL)theSelector withArguments:(NSArray *)arguments

{

// The first argument is the selector name, so ignore it

//

arguments = [arguments subarrayWithRange:NSMakeRange(1, [arguments count] - 1)];

for (id receiver in self.receivers)

{

if (![receiver respondsToSelector:theSelector])

continue;

NSMethodSignature* methodSig = [receiver methodSignatureForSelector:theSelector];

NSInvocation* inv = [NSInvocation invocationWithMethodSignature:methodSig];

[inv setSelector:theSelector];

[inv setArgumentsFromJavaScript:arguments];

[inv invokeWithTarget:receiver];

// Ignore return values...

break;

}

}

#pragma mark UIWebViewDelegate

- (void)webViewDidStartLoad:(UIWebView *)webView

{

if ([m_delegate respondsToSelector:@selector(webViewDidStartLoad:)])

[m_delegate webViewDidStartLoad:webView];

}

- (void)webViewDidFinishLoad:(UIWebView *)webView

{

// Load the GAJavaScript runtime before calling the delegate, because the delegate may

// want to use features of the library.

[self loadScriptRuntime];

if ([m_delegate respondsToSelector:@selector(webViewDidFinishLoad:)])

[m_delegate webViewDidFinishLoad:webView];

}

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request

navigationType:(UIWebViewNavigationType)navigationType

{

NSURL* theUrl = [request URL];

if ([[theUrl scheme] isEqualToString:@"ga-js"])

{

if ([[theUrl resourceSpecifier] isEqualToString:@"makeLotsaCalls"])

{

[self makeLotsaCalls];

}

return NO;

}

// Let the delegate handle it if we have one.

if ([m_delegate respondsToSelector:@selector(webView:shouldStartLoadWithRequest:navigationType:)])

return [m_delegate webView:webView shouldStartLoadWithRequest:request navigationType:navigationType];

// TODO: Only YES for the inital HTML page

return YES;

}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error

{

if ([m_delegate respondsToSelector:@selector(webView:didFailLoadWithError:)])

[m_delegate webView:webView didFailLoadWithError:error];

}

@end