OSX/libsecurity_transform/lib/StreamSource.cpp

   1 #include "StreamSource.h"
   2 #include <string>
   3 #include "misc.h"
   4
   5 using namespace std;
   6
   7 CFStringRef gStreamSourceName = CFSTR("StreamSource");
   8
   9 const CFIndex kMaximumSize = 2048;
  10
  11 StreamSource::StreamSource(CFReadStreamRef input, Transform* transform, CFStringRef name)
  12         : Source(gStreamSourceName, transform, name),
  13         mReadStream(input),
  14         mReading(dispatch_group_create())
  15 {
  16         dispatch_group_enter(mReading);
  17         CFRetain(mReadStream);
  18 }
  19
  20 void StreamSource::BackgroundActivate()
  21 {
  22         CFIndex result = 0;
  23
  24         do
  25         {
  26                 // make a buffer big enough to handle the object
  27                 // NOTE: allocating this on the stack and letting CFDataCreate copy it is _faster_ then malloc and CFDataCreateWithBytes(..., kCFAllactorMalloc) by a fair margin.   At least for 2K chunks.   Retest if changing the size.
  28                 UInt8 buffer[kMaximumSize];
  29
  30                 result = CFReadStreamRead(mReadStream, buffer, kMaximumSize);
  31
  32                 if (result > 0) // was data returned?
  33                 {
  34                         // make the data and send it to the transform
  35                         CFDataRef data = CFDataCreate(NULL, buffer, result);
  36
  37                         CFErrorRef error = mDestination->SetAttribute(mDestinationName, data);
  38
  39                         CFRelease(data);
  40
  41                         if (error != NULL) // we have a problem, there was probably an abort on the chain
  42                         {
  43                                 return; // quiesce the source
  44                         }
  45                 }
  46         } while (result > 0);
  47
  48         if (result < 0)
  49         {
  50                 // we got an error!
  51                 CFErrorRef error = CFReadStreamCopyError(mReadStream);
  52                 mDestination->SetAttribute(mDestinationName, error);
  53                 if (error)
  54                 {
  55                         // NOTE: CF doesn't always tell us about this error.   Arguably it could be better to
  56                         // "invent" a generic error, but it is a hard argument that we want to crash in CFRelease(NULL)...
  57                         CFRelease(error);
  58                 }
  59         }
  60         else
  61         {
  62                 // send an EOS
  63                 mDestination->SetAttribute(mDestinationName, NULL); // end of stream
  64         }
  65 }
  66
  67 void StreamSource::DoActivate()
  68 {
  69         CFRetain(mDestination->GetCFObject());
  70         dispatch_group_async(mReading, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
  71                 this->BackgroundActivate();
  72                 CFRelease(mDestination->GetCFObject());
  73         });
  74         dispatch_group_leave(mReading);
  75 }
  76
  77 void StreamSource::Finalize()
  78 {
  79         dispatch_group_notify(mReading, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
  80                 delete this;
  81         });
  82 }
  83
  84 StreamSource::~StreamSource()
  85 {
  86         CFRelease(mReadStream);
  87         mReadStream = NULL;
  88         dispatch_release(mReading);
  89         mReading = NULL;
  90 }
  91
  92
  93 Boolean StreamSource::Equal(const CoreFoundationObject* object)
  94 {
  95         // not equal if we are not the same object
  96         if (Source::Equal(object))
  97         {
  98                 const StreamSource* ss = (StreamSource*) object;
  99                 return CFEqual(ss->mReadStream, mReadStream);
 100         }
 101
 102         return false;
 103 }
 104
 105
 106
 107 CFTypeRef StreamSource::Make(CFReadStreamRef input, Transform* transform, CFStringRef name)
 108 {
 109         return CoreFoundationHolder::MakeHolder(gInternalCFObjectName, new StreamSource(input, transform, name));
 110 }
 111
 112
 113
 114 string StreamSource::DebugDescription()
 115 {
 116         string result = Source::DebugDescription() + ": Stream ";
 117
 118         char buffer[256];
 119         snprintf(buffer, sizeof(buffer), "(mReadStream = %p)", mReadStream);
 120
 121         result += buffer;
 122
 123         return result;
 124 }