static ClassFileWriter()
{
// Used to find blocks of code with no dependencies (aka dead code).
// Necessary for generating type information for dead code, which is
// expected by the Sun verifier. It is only necessary to store a single
// jump source to determine if a block is reachable or not.
// Figure out which classfile version should be generated. This assumes
// that the runtime used to compile the JavaScript files is the same as
// the one used to run them. This is important because there are cases
// when bytecode is generated at runtime, where it is not easy to pass
// along what version is necessary. Instead, we grab the version numbers
// from the bytecode of this class and use that.
//
// Based on the version numbers we scrape, we can also determine what
// bytecode features we need. For example, Java 6 bytecode (classfile
// version 50) should have stack maps generated.
Stream @is = null;
int major = 48;
int minor = 0;
try
{
@is = typeof(ClassFileWriter).GetResourceAsStream("ClassFileWriter.class");
if (@is == null)
{
@is = ClassLoader.GetSystemResourceAsStream("org/mozilla/classfile/ClassFileWriter.class");
}
byte[] header = new byte[8];
// read loop is required since JDK7 will only provide 2 bytes
// on the first read() - see bug #630111
int read = 0;
while (read < 8)
{
int c = @is.Read(header, read, 8 - read);
if (c < 0)
{
throw new IOException();
}
read += c;
}
minor = (header[4] << 8) | (header[5] & unchecked((int)(0xff)));
major = (header[6] << 8) | (header[7] & unchecked((int)(0xff)));
}
catch (Exception)
{
}
finally
{
// Unable to get class file, use default bytecode version
MinorVersion = minor;
MajorVersion = major;
GenerateStackMap = major >= 50;
if (@is != null)
{
try
{
@is.Close();
}
catch (IOException)
{
}
}
}
}
