Issue #41 - Bring method of determining IE version up to date

src/shared/IE_version.cpp

 #include "IE_version.h"
 #include "Registry.h"
+#include <cstdlib>
 
 using namespace AdblockPlus;
 
 /**
  * Internal implementation of the IE version string.
  *
  * This version throws exceptions for its errors, relying on its caller to handle them.
  *
  * Quoting http://support.microsoft.com/kb/969393:
  *   "Note The version string value for Internet Explorer 10 is 9.10.9200.16384, and the svcVersion string value is 10.0.9200.16384."
  * [EH 2014-06-20] My current version of IE 11 is reporting these values:
  *   Version 9.11.9600.17041
  *   svcVersion 11.0.9600.17041
  *
  * Warning: IE version 12 and later might not behave the same, so this function should be reviewed with each new release.
+ *
+ * \par postcondition
+ *   Return value matches regex `^[0-9]{1,2}\.$`; this is a sanity check on the format.
  */
-std::wstring IE_version_string()
+std::wstring IeVersionString()
 {
-  Registry_Key IE_key(Registry_Key::Predefined::HKLM, L"Software\\Microsoft\\Internet Explorer");
-  std::wstring version(IE_key.value_wstring(L"Version"));
+  RegistryKey ieKey(HKEY_LOCAL_MACHINE, L"Software\\Microsoft\\Internet Explorer");
+  std::wstring version(ieKey.value_wstring(L"Version"));
   /*
-    * We're expecting a version string that matches the regex "^[1-9]\.".
-    * Since IE versions 10 and 11 use a version string that begins with "9.", this simplistic parsing method works adequately.
-    */
-  if (version[1] != '.' || version[0] < L'0' || version[0] > L'9')
+   * We're expecting a version string that matches the regex "^[1-9]\.".
+   * Since IE versions 10 and 11 use a version string that begins with "9.", this simplistic parsing method works adequately.
+   */
+  if (version.length() < 2 || version[1] != '.' || version[0] < L'0' || version[0] > L'9')
   {
     throw std::runtime_error("IE version string has unexpected format");
   }
   if (version[0] != L'9')
   {
     return version;
   }
   // Assert the major version in the "Version" value is 9.
   /*
-    * Version 9 might either be an actual version 9 or it might represent a version >= 10
-    * If the value named "svcVersion" exists, we'll report that instead.
-    */
+   * Version 9 might either be an actual version 9 or it might represent a version >= 10
+   * If the value named "svcVersion" exists, we'll report that instead.
+   */
   try
   {
-    return IE_key.value_wstring(L"svcVersion");
+    version = ieKey.value_wstring(L"svcVersion"); // throws if value not found
   }
   catch (...)
   {
+    // Assert svcVersion value not found
+    // Thus the major version is 9
     return version;
+  } 
+  // Assert major version is >= 10
+  if (version.length() < 3 || version[0] < L'0' || version[0] > L'9' || version[1] < L'0' || version[1] > L'9' || version[2] != L'.')
+  {
+    throw std::runtime_error("IE version string has unexpected format");
   }
+  return version;
 }
 
-std::wstring AdblockPlus::IE::installed_version_string()
+std::wstring AdblockPlus::IE::InstalledVersionString()
 {
   try
   {
-    return IE_version_string();
+    return IeVersionString();
   }
   catch (...)
   {
     return L"";
   }
 }
 
-int AdblockPlus::IE::installed_major_version()
+int AdblockPlus::IE::InstalledMajorVersion()
 {
   try
   {
-    std::wstring version = IE_version_string();
+    std::wstring version = IeVersionString();
     /*
-     * If the second character is a period, we assume that the major version is a single digit.
+     * The version number is either one or two digits,
+     *   and thus either the second or third character is a period,
      */
-    if (version[ 1 ] == L'.')
+    if (version[1] == L'.')
     {
-      return version[ 0 ] - L'0';
+      return version[0] - L'0';
+    } 
+    else if (version[2] == L'.')
+    {
+      return 10 * (version[0] - L'0') + (version[1] - L'0');
     }
-    // Assert IE_version_string() did not verify the syntax of the version string.
-    /*
-     * In this case, we'll assume that the version returned is two digits followed by a period.
-     * If not, we'll assume an error.
-     */
-    if (version[ 0 ] < L'0' || version[ 0 ] > L'9' || version[ 1 ] < L'0' || version[ 1 ] > L'9' || version[ 2 ] != L'.')
-    {
-      return 0;
-    }
-    return 10 * (version[ 0 ] - L'0') + (version[ 1 ] - L'0');
   }
   catch (...)
   {
-    return 0;
   }
+  return 0;
 }