began node hashing for improved cache

app/decoder/decoder.h

@@ -160,6 +160,13 @@ public:
    */
   virtual void Close() = 0;
 
+  /**
+   * @brief Get a media file's internal timestamp
+   *
+   * Used to determine which frame will be served at a given time, useful for caching.
+   */
+  virtual int64_t GetTimestampFromTime(const rational& time) = 0;
+
   /**
    * @brief Try to probe a Footage file by passing it through all available Decoders
    *

app/decoder/ffmpeg/ffmpegdecoder.cpp

@@ -195,10 +195,7 @@ FramePtr FFmpegDecoder::Retrieve(const rational &timecode, const rational &lengt
   }
 
   // Convert timecode to AVStream timebase
-  int64_t target_ts = qFloor(timecode.toDouble() * rational(avstream_->time_base).flipped().toDouble());
-
-  // Find closest actual timebase in the file
-  target_ts = GetClosestTimestampInIndex(target_ts);
+  int64_t target_ts = GetTimestampFromTime(timecode);
 
   if (target_ts < 0) {
     Error(tr("Index failed to produce a valid timestamp"));
@@ -323,6 +320,21 @@ QString FFmpegDecoder::id()
   return "ffmpeg";
 }
 
+int64_t FFmpegDecoder::GetTimestampFromTime(const rational &time)
+{
+  if (!open_ && !Open()) {
+    return -1;
+  }
+
+  // Convert timecode to AVStream timebase
+  int64_t target_ts = qFloor(time.toDouble() * rational(avstream_->time_base).flipped().toDouble());
+
+  // Find closest actual timebase in the file
+  target_ts = GetClosestTimestampInIndex(target_ts);
+
+  return target_ts;
+}
+
 bool FFmpegDecoder::Probe(Footage *f)
 {
   if (open_) {

app/decoder/ffmpeg/ffmpegdecoder.h

@@ -51,6 +51,8 @@ public:
 
   virtual QString id() override;
 
+  virtual int64_t GetTimestampFromTime(const rational& time) override;
+
 private:
   /**
    * @brief Handle an error
@@ -117,6 +119,8 @@ private:
    */
   void SaveFrameIndex();
 
+  int64_t GetClosestTimestampInIndex(const int64_t& ts);
+
   /**
    * @brief Returns an AVPixelFormat that can be
    * @param pix_fmt
@@ -124,8 +128,6 @@ private:
    */
   AVPixelFormat GetCompatiblePixelFormat(const AVPixelFormat& pix_fmt);
 
-  int64_t GetClosestTimestampInIndex(const int64_t& ts);
-
   AVFormatContext* fmt_ctx_;
   AVCodecContext* codec_ctx_;
   AVStream* avstream_;

app/node/input/media/media.cpp

@@ -97,6 +97,18 @@ void MediaInput::SetFootage(Footage *f)
   footage_input_->set_value(PtrToValue(f));
 }
 
+void MediaInput::Hash(QCryptographicHash *hash, const rational &time)
+{
+  Node::Hash(hash, time);
+
+  // Use frame value from Decoder
+  if (SetupDecoder()) {
+    hash->addData(QString::number(decoder_->GetTimestampFromTime(time)).toUtf8());
+    // FIXME: Add OCIO data
+    // FIXME: Add alpha association value
+  }
+}
+
 QVariant MediaInput::Value(NodeOutput *output, const rational &time)
 {
   // FIXME: Hardcoded value
@@ -111,27 +123,11 @@ QVariant MediaInput::Value(NodeOutput *output, const rational &time)
       return 0;
     }
 
-    // Get currently selected Footage
-    Footage* footage = ValueToPtr<Footage>(footage_input_->get_value(time));
-
-    // If no footage is selected, return nothing
-    if (footage == nullptr) {
+    // Make sure decoder is set up
+    if (!SetupDecoder()) {
       return 0;
     }
 
-    // Otherwise try to get frame of footage from decoder
-
-    // Determine which decoder to use
-    if (decoder_ == nullptr
-        && (decoder_ = Decoder::CreateFromID(footage->decoder())) == nullptr) {
-      return 0;
-    }
-
-    if (decoder_->stream() == nullptr) {
-      // FIXME: Hardcoded stream 0
-      decoder_->set_stream(footage->stream(0));
-    }
-
     // Get frame from Decoder
     FramePtr frame = decoder_->Retrieve(time);
 
@@ -247,3 +243,33 @@ QVariant MediaInput::Value(NodeOutput *output, const rational &time)
 
   return 0;
 }
+
+bool MediaInput::SetupDecoder()
+{
+  if (decoder_ != nullptr) {
+    return true;
+  }
+
+  // Get currently selected Footage
+  Footage* footage = ValueToPtr<Footage>(footage_input_->get_value(0));
+
+  // If no footage is selected, return nothing
+  if (footage == nullptr) {
+    return false;
+  }
+
+  // Otherwise try to get frame of footage from decoder
+
+  // Determine which decoder to use
+  if (decoder_ == nullptr
+      && (decoder_ = Decoder::CreateFromID(footage->decoder())) == nullptr) {
+    return false;
+  }
+
+  if (decoder_->stream() == nullptr) {
+    // FIXME: Hardcoded stream 0
+    decoder_->set_stream(footage->stream(0));
+  }
+
+  return true;
+}

app/node/input/media/media.h

@@ -51,10 +51,16 @@ public:
 
   void SetFootage(Footage* f);
 
+  virtual void Hash(QCryptographicHash *hash, const rational &time) override;
+
+
+
 protected:
   virtual QVariant Value(NodeOutput* output, const rational& time) override;
 
 private:
+  bool SetupDecoder();
+
   NodeInput* footage_input_;
 
   NodeInput* matrix_input_;

app/node/node.cpp

@@ -279,6 +279,29 @@ bool Node::OutputsTo(Node *n)
   return false;
 }
 
+void Node::Hash(QCryptographicHash *hash, NodeOutput* from, const rational &time)
+{
+  // Add this Node's ID
+  hash->addData(id().toUtf8());
+
+  // Add each value
+  QList<NodeParam*> params = parameters();
+  foreach (NodeParam* param, params) {
+    if (param->type() == NodeParam::kInput && !param->IsConnected()) {
+      // Get the value at this time
+      QVariant v = static_cast<NodeInput*>(param)->get_value(time);
+      hash->addData(v.toByteArray()); // FIXME: Does this work on all value types?
+    }
+  }
+
+  // Add each dependency node
+  QList<NodeDependency> deps = RunDependencies(from, time);
+  foreach (const NodeDependency& dep, deps) {
+    // Hash the connected node
+    dep.node()->parent()->Hash(hash, dep.node(), time);
+  }
+}
+
 QVariant Node::PtrToValue(void *ptr)
 {
   return reinterpret_cast<quintptr>(ptr);

app/node/node.h

@@ -21,6 +21,7 @@
 #ifndef NODE_H
 #define NODE_H
 
+#include <QCryptographicHash>
 #include <QMutex>
 #include <QObject>
 
@@ -147,6 +148,11 @@ public:
    */
   bool OutputsTo(Node* n);
 
+  /**
+   * @brief Add's unique information about this Node at the given time to a QCryptographicHash
+   */
+  virtual void Hash(QCryptographicHash* hash, NodeOutput *from, const rational& time);
+
   /**
    * @brief Convert a pointer to a value that can be sent between NodeParams
    */