Minor warning fix, and improvement to transaction signing API

CoreBitcoin/BTCBase58.m

@@ -27,7 +27,7 @@
     __block BIGNUM bn;     BN_init(&bn);     BN_zero(&bn);
     __block BIGNUM bnChar; BN_init(&bnChar);
 
-    void(^finish)() = ^{
+    void(^finish)(void) = ^{
         if (pctx) BN_CTX_free(pctx);
         BN_clear_free(&bn58);
         BN_clear_free(&bn);
@@ -134,7 +134,7 @@
     __block BIGNUM dv; BN_init(&dv); BN_zero(&dv);
     __block BIGNUM rem; BN_init(&rem); BN_zero(&rem);
 
-    void(^finish)() = ^{
+    void(^finish)(void) = ^{
         if (pctx) BN_CTX_free(pctx);
         BN_clear_free(&bn58);
         BN_clear_free(&bn0);

CoreBitcoin/BTCTransaction.h

@@ -11,6 +11,7 @@ static const BTCAmount BTCTransactionDefaultFeeRate = 10000; // 10K satoshis per
 @class BTCScript;
 @class BTCTransactionInput;
 @class BTCTransactionOutput;
+@class BTCKey;
 
 /*!
  * Converts string transaction ID (reversed tx hash in hex format) to transaction hash.
@@ -128,6 +129,9 @@ NSString* BTCTransactionIDFromHash(NSData* txhash) DEPRECATED_ATTRIBUTE;
 // You should supply the output script of the previous transaction, desired hash type and input index in this transaction.
 - (NSData*) signatureHashForScript:(BTCScript*)subscript inputIndex:(uint32_t)inputIndex hashType:(BTCSignatureHashType)hashType error:(NSError**)errorOut;
 
+// Attempts to sign the index at position i with key, returns failure / success
+- (BOOL)attemptToSignInputAtIndex:(uint32_t)i withKey:(BTCKey *)key error:(NSError **)errorOut;
+
 // Adds input script
 - (void) addInput:(BTCTransactionInput*)input;
 

CoreBitcoin/BTCTransaction.m

@@ -8,6 +8,8 @@
 #import "BTCScript.h"
 #import "BTCErrors.h"
 #import "BTCHashID.h"
+#import "BTCKey.h"
+#import "BTCAddress.h"
 
 NSData* BTCTransactionHashFromID(NSString* txid) {
     return BTCHashFromID(txid);
@@ -335,7 +337,52 @@ - (BOOL) parseStream:(NSInputStream*)stream {
 
 #pragma mark - Signing a transaction
 
+// Attempts to sign the index at position i with key, returns failure / success
+- (BOOL)attemptToSignInputAtIndex:(uint32_t)i withKey:(BTCKey *)key error:(NSError **)errorOut
+{
+    BTCTransactionInput *txin = self.inputs[i];
+
+    // We stored output script here earlier.
+    BTCScript* outputScript = txin.signatureScript;
+
+    NSData* cpk = key.compressedPublicKey;
+    NSData* ucpk = key.uncompressedPublicKey;
+
+    BTCSignatureHashType hashtype = SIGHASH_ALL;
+
+    NSData* sighash = [self signatureHashForScript:[outputScript copy] inputIndex:i hashType:hashtype error:errorOut];
+    if (!sighash) {
+        return NO;
+    }
+
+    // Most common case: P2PKH with compressed pubkey (because of BIP32)
+    BTCScript* p2cpkhScript = [[BTCScript alloc] initWithAddress:[BTCPublicKeyAddress addressWithData:BTCHash160(cpk)]];
+    if ([outputScript.data isEqual:p2cpkhScript.data]) {
+        txin.signatureScript = [[[BTCScript new] appendData:[key signatureForHash:sighash hashType:hashtype]] appendData:cpk];
+        return YES;
+    }
+
+    // Less common case: P2PKH with uncompressed pubkey (when not using BIP32)
+    BTCScript* p2ucpkhScript = [[BTCScript alloc] initWithAddress:[BTCPublicKeyAddress addressWithData:BTCHash160(ucpk)]];
+    if ([outputScript.data isEqual:p2ucpkhScript.data]) {
+        txin.signatureScript = [[[BTCScript new] appendData:[key signatureForHash:sighash hashType:hashtype]] appendData:ucpk];
+        return YES;
+    }
+
+    BTCScript* p2cpkScript = [[[BTCScript new] appendData:cpk] appendOpcode:OP_CHECKSIG];
+    BTCScript* p2ucpkScript = [[[BTCScript new] appendData:ucpk] appendOpcode:OP_CHECKSIG];
+
+    if ([outputScript.data isEqual:p2cpkScript] ||
+        [outputScript.data isEqual:p2ucpkScript]) {
+        txin.signatureScript = [[BTCScript new] appendData:[key signatureForHash:sighash hashType:hashtype]];
+        return YES;
+    } else {
+        // Not supported script type.
+        // Try custom signature.
+    }
 
+    return NO;
+}
 
 // Hash for signing a transaction.
 // You should supply the output script of the previous transaction, desired hash type and input index in this transaction.

CoreBitcoin/BTCTransactionBuilder.m

@@ -294,41 +294,7 @@ - (BOOL) attemptToSignTransactionInput:(BTCTransactionInput*)txin tx:(BTCTransac
     }
 
     if (key) {
-        NSData* cpk = key.compressedPublicKey;
-        NSData* ucpk = key.uncompressedPublicKey;
-
-        BTCSignatureHashType hashtype = SIGHASH_ALL;
-
-        NSData* sighash = [tx signatureHashForScript:[outputScript copy] inputIndex:i hashType:hashtype error:errorOut];
-        if (!sighash) {
-            return NO;
-        }
-
-        // Most common case: P2PKH with compressed pubkey (because of BIP32)
-        BTCScript* p2cpkhScript = [[BTCScript alloc] initWithAddress:[BTCPublicKeyAddress addressWithData:BTCHash160(cpk)]];
-        if ([outputScript.data isEqual:p2cpkhScript.data]) {
-            txin.signatureScript = [[[BTCScript new] appendData:[key signatureForHash:sighash hashType:hashtype]] appendData:cpk];
-            return YES;
-        }
-
-        // Less common case: P2PKH with uncompressed pubkey (when not using BIP32)
-        BTCScript* p2ucpkhScript = [[BTCScript alloc] initWithAddress:[BTCPublicKeyAddress addressWithData:BTCHash160(ucpk)]];
-        if ([outputScript.data isEqual:p2ucpkhScript.data]) {
-            txin.signatureScript = [[[BTCScript new] appendData:[key signatureForHash:sighash hashType:hashtype]] appendData:ucpk];
-            return YES;
-        }
-
-        BTCScript* p2cpkScript = [[[BTCScript new] appendData:cpk] appendOpcode:OP_CHECKSIG];
-        BTCScript* p2ucpkScript = [[[BTCScript new] appendData:ucpk] appendOpcode:OP_CHECKSIG];
-
-        if ([outputScript.data isEqual:p2cpkScript] ||
-            [outputScript.data isEqual:p2ucpkScript]) {
-            txin.signatureScript = [[BTCScript new] appendData:[key signatureForHash:sighash hashType:hashtype]];
-            return YES;
-        } else {
-            // Not supported script type.
-            // Try custom signature.
-        }
+        [tx attemptToSignInputAtIndex:i withKey:key error:errorOut];
     } // if key
 
     // Ask to sign the transaction input to sign this if that's some kind of special input or script.