Use the return value to signal success for VTTParser helpers

Source/core/html/track/vtt/VTTParser.cpp

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include "core/dom/Text.h"
 #include "core/html/track/vtt/VTTElement.h"
 #include "platform/text/SegmentedString.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
 const double secondsPerHour = 3600;
 const double secondsPerMinute = 60;
 const double secondsPerMillisecond = 0.001;
-const double malformedTime = -1;
 const unsigned fileIdentifierLength = 6;
 
 static unsigned scanDigits(const String& input, unsigned* position)
 {
     unsigned startPosition = *position;
     while (*position < input.length() && isASCIIDigit(input[*position]))
         (*position)++;
     return *position - startPosition;
 }
 
@@ skipping 27 matching lines @@
         string.append(input[(*position)++]);
     return string.toString();
 }
 
 void VTTParser::skipWhiteSpace(const String& line, unsigned* position)
 {
     while (*position < line.length() && isASpace(line[*position]))
         (*position)++;
 }
 
-float VTTParser::parseFloatPercentageValue(const String& value, bool& isValidSetting)
+bool VTTParser::parseFloatPercentageValue(const String& value, float& percentage)
 {
     // '%' must be present and at the end of the setting value.
-    if (value.find('%', 1) != value.length() - 1) {
-        isValidSetting = false;
-        return 0;
-    }
+    if (value.isEmpty() || value[value.length() - 1] != '%')
+        return false;
 
     unsigned position = 0;
     unsigned digitsBeforeDot = scanDigits(value, &position);
     unsigned digitsAfterDot = 0;
     if (value[position] == '.') {
         position++;
 
         digitsAfterDot = scanDigits(value, &position);
     }
 
     // At least one digit required.
-    if (!digitsBeforeDot && !digitsAfterDot) {
-        isValidSetting = false;
-        return 0;
-    }
+    if (!digitsBeforeDot && !digitsAfterDot)
+        return false;
 
     float number = value.toFloat();
-    isValidSetting = number >= 0 && number <= 100;
-    return number;
+    if (number < 0 || number > 100)
+        return false;
+
+    percentage = number;
+    return true;
 }
 
-FloatPoint VTTParser::parseFloatPercentageValuePair(const String& value, char delimiter, bool& isValidSetting)
+bool VTTParser::parseFloatPercentageValuePair(const String& value, char delimiter, FloatPoint& valuePair)
 {
     // The delimiter can't be the first or second value because a pair of
     // percentages (x%,y%) implies that at least the first two characters
     // are the first percentage value.
     size_t delimiterOffset = value.find(delimiter, 2);
-    if (delimiterOffset == kNotFound || delimiterOffset == value.length() - 1) {
-        isValidSetting = false;
-        return FloatPoint(0, 0);
-    }
+    if (delimiterOffset == kNotFound || delimiterOffset == value.length() - 1)
+        return false;
 
-    bool isFirstValueValid;
-    float firstCoord = parseFloatPercentageValue(value.substring(0, delimiterOffset), isFirstValueValid);
+    float firstCoord;
+    if (!parseFloatPercentageValue(value.substring(0, delimiterOffset), firstCoord))
+        return false;
 
-    bool isSecondValueValid;
-    float secondCoord = parseFloatPercentageValue(value.substring(delimiterOffset + 1, value.length() - 1), isSecondValueValid);
+    float secondCoord;
+    if (!parseFloatPercentageValue(value.substring(delimiterOffset + 1, value.length() - 1), secondCoord))
+        return false;
 
-    isValidSetting = isFirstValueValid && isSecondValueValid;
-    return FloatPoint(firstCoord, secondCoord);
+    valuePair = FloatPoint(firstCoord, secondCoord);
+    return true;
 }
 
 VTTParser::VTTParser(VTTParserClient* client, Document& document)
     : m_document(&document)
     , m_state(Initial)
     , m_decoder(TextResourceDecoder::create("text/plain", UTF8Encoding()))
     , m_currentStartTime(0)
     , m_currentEndTime(0)
     , m_client(client)
 {
@@ skipping 157 matching lines @@
 }
 
 VTTParser::ParseState VTTParser::collectTimingsAndSettings(const String& line)
 {
     // Collect WebVTT cue timings and settings. (5.3 WebVTT cue timings and settings parsing.)
     // Steps 1 - 3 - Let input be the string being parsed and position be a pointer into input.
     unsigned position = 0;
     skipWhiteSpace(line, &position);
 
     // Steps 4 - 5 - Collect a WebVTT timestamp. If that fails, then abort and return failure. Otherwise, let cue's text track cue start time be the collected time.
-    m_currentStartTime = collectTimeStamp(line, &position);
-    if (m_currentStartTime == malformedTime)
+    if (!collectTimeStamp(line, &position, m_currentStartTime))
         return BadCue;
     if (position >= line.length())
         return BadCue;
 
     skipWhiteSpace(line, &position);
 
     // Steps 6 - 9 - If the next three characters are not "-->", abort and return failure.
     if (line.find("-->", position) == kNotFound)
         return BadCue;
     position += 3;
     if (position >= line.length())
         return BadCue;
 
     skipWhiteSpace(line, &position);
 
     // Steps 10 - 11 - Collect a WebVTT timestamp. If that fails, then abort and return failure. Otherwise, let cue's text track cue end time be the collected time.
-    m_currentEndTime = collectTimeStamp(line, &position);
-    if (m_currentEndTime == malformedTime)
+    if (!collectTimeStamp(line, &position, m_currentEndTime))
         return BadCue;
     skipWhiteSpace(line, &position);
 
     // Step 12 - Parse the WebVTT settings for the cue (conducted in TextTrackCue).
     m_currentSettings = line.substring(position, line.length()-1);
     return CueText;
 }
 
 VTTParser::ParseState VTTParser::collectCueText(const String& line)
 {
@@ skipping 117 matching lines @@
         if (m_regionList[i]->id() == region->id()) {
             m_regionList.remove(i);
             break;
         }
     }
 
     // Step 12.5.11
     m_regionList.append(region);
 }
 
-double VTTParser::collectTimeStamp(const String& line, unsigned* position)
+bool VTTParser::collectTimeStamp(const String& line, unsigned* position, double& timeStamp)
 {
     // Collect a WebVTT timestamp (5.3 WebVTT cue timings and settings parsing.)
     // Steps 1 - 4 - Initial checks, let most significant units be minutes.
     enum Mode { Minutes, Hours };
     Mode mode = Minutes;
 
     // Steps 5 - 7 - Collect a sequence of characters that are 0-9.
     // If not 2 characters or value is greater than 59, interpret as hours.
     int value1;
     unsigned value1Digits = collectDigitsToInt(line, position, value1);
     if (!value1Digits)
-        return malformedTime;
+        return false;
     if (value1Digits != 2 || value1 > 59)
         mode = Hours;
 
     // Steps 8 - 11 - Collect the next sequence of 0-9 after ':' (must be 2 chars).
     if (*position >= line.length() || line[(*position)++] != ':')
-        return malformedTime;
+        return false;
     int value2;
     if (collectDigitsToInt(line, position, value2) != 2)
-        return malformedTime;
+        return false;
 
     // Step 12 - Detect whether this timestamp includes hours.
     int value3;
     if (mode == Hours || (*position < line.length() && line[*position] == ':')) {
         if (*position >= line.length() || line[(*position)++] != ':')
-            return malformedTime;
+            return false;
         if (collectDigitsToInt(line, position, value3) != 2)
-            return malformedTime;
+            return false;
     } else {
         value3 = value2;
         value2 = value1;
         value1 = 0;
     }
 
     // Steps 13 - 17 - Collect next sequence of 0-9 after '.' (must be 3 chars).
     if (*position >= line.length() || line[(*position)++] != '.')
-        return malformedTime;
+        return false;
     int value4;
     if (collectDigitsToInt(line, position, value4) != 3)
-        return malformedTime;
+        return false;
     if (value2 > 59 || value3 > 59)
-        return malformedTime;
+        return false;
 
     // Steps 18 - 19 - Calculate result.
-    return (value1 * secondsPerHour) + (value2 * secondsPerMinute) + value3 + (value4 * secondsPerMillisecond);
+    timeStamp = (value1 * secondsPerHour) + (value2 * secondsPerMinute) + value3 + (value4 * secondsPerMillisecond);
+    return true;
 }
 
 static VTTNodeType tokenToNodeType(VTTToken& token)
 {
     switch (token.name().length()) {
     case 1:
         if (token.name()[0] == 'c')
             return VTTNodeTypeClass;
         if (token.name()[0] == 'v')
             return VTTNodeTypeVoice;
@@ skipping 77 matching lines @@
         }
         if (nodeType == VTTNodeTypeLanguage)
             m_languageStack.removeLast();
         if (m_currentNode->parentNode())
             m_currentNode = m_currentNode->parentNode();
         break;
     }
     case VTTTokenTypes::TimestampTag: {
         unsigned position = 0;
         String charactersString = m_token.characters();
-        double time = VTTParser::collectTimeStamp(charactersString, &position);
-        if (time != malformedTime)
+        double parsedTimeStamp;
+        if (VTTParser::collectTimeStamp(charactersString, &position, parsedTimeStamp))
             m_currentNode->parserAppendChild(ProcessingInstruction::create(document, "timestamp", charactersString));
         break;
     }
     default:
         break;
     }
 }
 
 }