Fix comparison of forward-declared and fully visible types

third_party/ocmock/OCMock/OCMBoxedReturnValueProvider.m

+//---------------------------------------------------------------------------------------
+//  $Id$
+//  Copyright (c) 2009 by Mulle Kybernetik. See License file for details.
+//---------------------------------------------------------------------------------------
+
+#import "OCMBoxedReturnValueProvider.h"
+
+static const char* OCMTypeWithoutQualifiers(const char* objCType)
+{
+    while(strchr("rnNoORV", objCType[0]) != NULL)
+        objCType += 1;
+    return objCType;
+}
+
+/*
+ * Sometimes an external type is an opaque struct (which will have an @encode of "{structName}"
+ * or "{structName=}") but the actual method return type, or property type, will know the contents
+ * of the struct (so will have an objcType of say "{structName=iiSS}".  This function will determine
+ * those are equal provided they have the same structure name, otherwise everything else will be
+ * compared textually.  This can happen particularly for pointers to such structures, which still
+ * encode what is being pointed to.
+ */
+static BOOL OCMTypesEqualAllowOpaqueStructs(const char *type1, const char *type2)
+{
+    type1 = OCMTypeWithoutQualifiers(type1);
+    type2 = OCMTypeWithoutQualifiers(type2);
+
+    switch (type1[0])
+    {
+        case '{':
+        case '(':
+        {
+            if (type2[0] != type1[0])
+                return NO;
+            char endChar = type1[0] == '{'? '}' : ')';
+            
+            const char *type1End = strchr(type1, endChar);
+            const char *type2End = strchr(type2, endChar);
+            const char *type1Equals = strchr(type1, '=');
+            const char *type2Equals = strchr(type2, '=');
+            
+            /* Opaque types either don't have an equals sign (just the name and the end brace), or
+             * empty content after the equals sign.
+             * We want that to compare the same as a type of the same name but with the content.
+             */
+            BOOL type1Opaque = (type1Equals == NULL || (type1End < type1Equals) || type1Equals[1] == endChar);
+            BOOL type2Opaque = (type2Equals == NULL || (type2End < type2Equals) || type2Equals[1] == endChar);
+            const char *type1NameEnd = (type1Equals == NULL || (type1End < type1Equals)) ? type1End : type1Equals;
+            const char *type2NameEnd = (type2Equals == NULL || (type2End < type2Equals)) ? type2End : type2Equals;
+            intptr_t type1NameLen = type1NameEnd - type1;
+            intptr_t type2NameLen = type2NameEnd - type2;
+            
+            /* If the names are not equal, return NO */
+            if (type1NameLen != type2NameLen || strncmp(type1, type2, type1NameLen))
+                return NO;
+            
+            /* If the same name, and at least one is opaque, that is close enough. */
+            if (type1Opaque || type2Opaque)
+                return YES;
+            
+            /* Otherwise, compare all the elements.  Use NSGetSizeAndAlignment to walk through the struct elements. */
+            type1 = type1Equals + 1;
+            type2 = type2Equals + 1;
+            while (type1[0] != endChar && type1[0] != '\0')
+            {
+                if (!OCMTypesEqualAllowOpaqueStructs(type1, type2))
+                    return NO;
+                type1 = NSGetSizeAndAlignment(type1, NULL, NULL);
+                type2 = NSGetSizeAndAlignment(type2, NULL, NULL);
+            }
+            return YES;
+        }
+        case '^':
+            /* for a pointer, make sure the other is a pointer, then recursively compare the rest */
+            if (type2[0] != type1[0])
+                return NO;
+            return OCMTypesEqualAllowOpaqueStructs(type1+1, type2+1);
+        
+        case '\0':
+            return type2[0] == '\0';
+
+        default:
+        {
+            // Move the type pointers past the current types, then compare that region
+            const char *afterType1 =  NSGetSizeAndAlignment(type1, NULL, NULL);
+            const char *afterType2 =  NSGetSizeAndAlignment(type2, NULL, NULL);
+            intptr_t type1Len = afterType1 - type1;
+            intptr_t type2Len = afterType2 - type2;
+            
+            return (type1Len == type2Len && (strncmp(type1, type2, type1Len) == 0));
+        }
+    }
+}
+
+static CFNumberType OCMNumberTypeForObjCType(const char *objcType)
+{
+    switch (objcType[0])
+    {
+        case 'c': return kCFNumberCharType;
+        case 'C': return kCFNumberCharType;
+        case 'B': return kCFNumberCharType;
+        case 's': return kCFNumberShortType;
+        case 'S': return kCFNumberShortType;
+        case 'i': return kCFNumberIntType;
+        case 'I': return kCFNumberIntType;
+        case 'l': return kCFNumberLongType;
+        case 'L': return kCFNumberLongType;
+        case 'q': return kCFNumberLongLongType;
+        case 'Q': return kCFNumberLongLongType;
+        case 'f': return kCFNumberFloatType;
+        case 'd': return kCFNumberDoubleType;
+    }
+    
+    return 0;
+}
+
+static NSNumber *OCMNumberForValue(NSValue *value)
+{
+#define CREATE_NUM(_type, _meth) ({ _type _v; [value getValue:&_v]; [NSNumber _meth _v]; })
+    switch ([value objCType][0])
+    {
+        case 'c': return CREATE_NUM(char,               numberWithChar:);
+        case 'C': return CREATE_NUM(unsigned char,      numberWithUnsignedChar:);
+        case 'B': return CREATE_NUM(bool,               numberWithBool:);
+        case 's': return CREATE_NUM(short,              numberWithShort:);
+        case 'S': return CREATE_NUM(unsigned short,     numberWithUnsignedShort:);
+        case 'i': return CREATE_NUM(int,                numberWithInt:);
+        case 'I': return CREATE_NUM(unsigned int,       numberWithUnsignedInt:);
+        case 'l': return CREATE_NUM(long,               numberWithLong:);
+        case 'L': return CREATE_NUM(unsigned long,      numberWithUnsignedLong:);
+        case 'q': return CREATE_NUM(long long,          numberWithLongLong:);
+        case 'Q': return CREATE_NUM(unsigned long long, numberWithUnsignedLongLong:);
+        case 'f': return CREATE_NUM(float,              numberWithFloat:);
+        case 'd': return CREATE_NUM(double,             numberWithDouble:);
+    }
+    
+    return nil;
+}
+
+@implementation OCMBoxedReturnValueProvider
+
+- (void)handleInvocation:(NSInvocation *)anInvocation
+{
+    const char *returnType = [[anInvocation methodSignature] methodReturnType];
+    NSUInteger returnTypeSize = [[anInvocation methodSignature] methodReturnLength];
+    char valueBuffer[returnTypeSize];
+    NSValue *value = (NSValue *)returnValue;
+    
+    if ([self getBytes:valueBuffer forValue:value compatibleWithType:returnType])
+    {
+        [anInvocation setReturnValue:valueBuffer];
+    }
+    else
+    {
+        [NSException raise:NSInvalidArgumentException
+                    format:@"Return value does not match method signature; signature declares '%s' but value is '%s'.", returnType, [value objCType]];
+    }
+}
+
+- (BOOL)isMethodReturnType:(const char *)returnType compatibleWithValueType:(const char *)valueType
+{
+    /* Allow void* for methods that return id, mainly to be able to handle nil */
+    if(strcmp(returnType, @encode(id)) == 0 && strcmp(valueType, @encode(void *)) == 0)
+        return YES;
+    
+    /* Same types are obviously compatible */
+    if(strcmp(returnType, valueType) == 0)
+        return YES;
+    
+    @try {
+        if(OCMTypesEqualAllowOpaqueStructs(returnType, valueType))
+            return YES;
+    }
+    @catch (NSException *e) {
+        /* Probably a bitfield or something that NSGetSizeAndAlignment chokes on, oh well */
+        return NO;
+    }
+
+    return NO;
+}
+
+- (BOOL)getBytes:(void *)outputBuf forValue:(NSValue *)inputValue compatibleWithType:(const char *)targetType
+{
+    /* If the types are directly compatible, use it */
+    if ([self isMethodReturnType:targetType compatibleWithValueType:[inputValue objCType]])
+    {
+        [inputValue getValue:outputBuf];
+        return YES;
+    }
+
+    /*
+     * See if they are similar number types, and if we can convert losslessly between them.
+     * For the most part, we set things up to use CFNumberGetValue, which returns false if
+     * conversion will be lossy.
+     */
+    CFNumberType inputType = OCMNumberTypeForObjCType([inputValue objCType]);
+    CFNumberType outputType = OCMNumberTypeForObjCType(targetType);
+    
+    if (inputType == 0 || outputType == 0) // one or both are non-number types
+        return NO;
+    
+
+    NSNumber *inputNumber = [inputValue isKindOfClass:[NSNumber class]]? (id)inputValue : OCMNumberForValue(inputValue);
+    
+    /*
+     * Due to some legacy, back-compatible requirements in CFNumber.c, CFNumberGetValue can return true for
+     * some conversions which should not be allowed (by reading source, conversions from integer types to
+     * 8-bit or 16-bit integer types).  So, check ourselves.
+     */
+    long long min = LLONG_MIN;
+    long long max = LLONG_MAX;
+    long long val = [inputNumber longLongValue];
+    switch (targetType[0])
+    {
+        case 'B':
+        case 'c': min = CHAR_MIN; max =  CHAR_MAX; break;
+        case 'C': min =        0; max = UCHAR_MAX; break;
+        case 's': min = SHRT_MIN; max =  SHRT_MAX; break;
+        case 'S': min =        0; max = USHRT_MAX; break;
+    }
+    if (val < min || val > max)
+        return NO;
+
+    /* Get the number, and return NO if the value was out of range or conversion was lossy */
+    return CFNumberGetValue((CFNumberRef)inputNumber, outputType, outputBuf);
+}
+
+@end