Only validate UTF-8 if we get UTF-8 input (UTF-16/32 validated at conversion)

source/dyaml/reader.d

@@ -121,14 +121,10 @@ final class Reader
 
             buffer8_ = utf8Result.utf8;
 
-            const validateResult = buffer8_.validateUTF8NoGC;
+            characterCount_ = utf8Result.characterCount;
-            enforce(validateResult.valid,
-                    new ReaderException(validateResult.msg ~
-                                        validateResult.sequence.to!string));
             // Check that all characters in buffer are printable.
             enforce(isPrintableValidUTF8(buffer8_),
                     new ReaderException("Special unicode characters are not allowed"));
-            characterCount_ = validateResult.characterCount;
 
             this.sliceBuilder = SliceBuilder(this);
         }
@@ -617,9 +613,10 @@ private:
 // A struct with the following members:
 //
 // $(D string errorMessage)   In case of an error, the error message is stored here. If
-//                          there was no error, errorMessage is NULL. Always check this
+//                            there was no error, errorMessage is NULL. Always check
-//                          first.
+//                            this first.
 // $(D char[] utf8)           input converted to UTF-8. May be a slice of input.
+// $(D size_t characterCount) Number of characters (code points) in input.
 auto toUTF8(ubyte[] input, const UTFEncoding encoding) @safe pure nothrow
 {
     // Documented in function ddoc.
@@ -627,6 +624,7 @@ auto toUTF8(ubyte[] input, const UTFEncoding encoding) @safe pure nothrow
     {
         string errorMessage;
         char[] utf8;
+        size_t characterCount;
     }
 
     Result result;
@@ -639,9 +637,7 @@ auto toUTF8(ubyte[] input, const UTFEncoding encoding) @safe pure nothrow
     // result = A Result struct to put encoded result and any error messages to.
     //
     // On error, result.errorMessage will be set.
-    static void encode(C)(C[] input, ref Result result) @safe pure nothrow
+    static void encode(C)(C[] input, ref Result result) @safe pure
-    {
-        try
     {
         // We can do UTF-32->UTF-8 in place because all UTF-8 sequences are 4 or
         // less bytes.
@@ -652,6 +648,7 @@ auto toUTF8(ubyte[] input, const UTFEncoding encoding) @safe pure nothrow
             auto length = 0;
             foreach(dchar c; input)
             {
+                ++result.characterCount;
                 // ASCII
                 if(c < 0x80)
                 {
@@ -674,20 +671,23 @@ auto toUTF8(ubyte[] input, const UTFEncoding encoding) @safe pure nothrow
         // Unfortunately we can't do UTF-16 in place so we just use std.conv.to
         else
         {
+            result.characterCount = std.utf.count(input);
             result.utf8 = input.to!(char[]);
         }
     }
-        catch(ConvException e) { result.errorMessage = e.msg; }
-        catch(UTFException e)  { result.errorMessage = e.msg; }
-        catch(Exception e)
-        {
-            assert(false, "Unexpected exception in encode(): " ~ e.msg);
-        }
-    }
 
-    final switch(encoding)
+    try final switch(encoding)
     {
-        case UTFEncoding.UTF_8:  result.utf8 = cast(char[])input; break;
+        case UTFEncoding.UTF_8:
+            result.utf8 = cast(char[])input;
+            const validateResult = result.utf8.validateUTF8NoGC();
+            if(!validateResult.valid)
+            {
+                result.errorMessage = "UTF-8 validation error: " ~ validateResult.msg ~
+                                      validateResult.sequence.to!string;
+            }
+            result.characterCount = validateResult.characterCount;
+            break;
         case UTFEncoding.UTF_16:
             assert(input.length % 2 == 0, "UTF-16 buffer size must be even");
             encode(cast(wchar[])input, result);
@@ -697,8 +697,12 @@ auto toUTF8(ubyte[] input, const UTFEncoding encoding) @safe pure nothrow
             encode(cast(dchar[])input, result);
             break;
     }
-
+    catch(ConvException e) { result.errorMessage = e.msg; }
-    if(result.errorMessage !is null) { return result; }
+    catch(UTFException e)  { result.errorMessage = e.msg; }
+    catch(Exception e)
+    {
+        assert(false, "Unexpected exception in encode(): " ~ e.msg);
+    }
 
     return result;
 }