Handle buffer overflows

micronaut-projects · Nov 13, 2019 · 613e267 · 613e267
1 parent 8a82029
commit 613e267
Showing 1 changed file with 21 additions and 18 deletions.
diff --git a/views-soy/src/main/java/io/micronaut/views/soy/SoyResponseBuffer.java b/views-soy/src/main/java/io/micronaut/views/soy/SoyResponseBuffer.java
@@ -158,26 +158,34 @@ ByteBuf exportChunk(int maxBytes) {
     return buffer.readSlice(Math.min(maxBytes, availableBytes)).asReadOnly().retain();
   }
 
-  private void ensureChunkSize(int size) {
-    if (chunk.capacity() > (chunk.writerIndex() + size)) {
-      // we need to allocate a new chunk real fast
-      buffer.addComponent(true, chunk);
-      chunk = allocateChunk();
-    } else {
-      chunk.ensureWritable(size);
-    }
-  }
-
   // -- Incoming Data -- //
 
   @Override
   public AdvisingAppendable append(CharSequence charSequence) {
     int size = charSequence.length();
-    ensureChunkSize(size);
+    int available = (chunk.capacity() - chunk.writerIndex() - 1);
+    int balance = available - size;
+    if (balance < 0) {
+      // there is not enough space for the whole write to fit, but perhaps a partial
+      // write can be performed
+      CharSequence subSequence = charSequence.subSequence(0, available);
+      charSequence = charSequence.subSequence(available + 1, Math.abs(balance));
+      chunk.writeCharSequence(subSequence, charset);
+
+      if (LOG.isTraceEnabled()) {
+        LOG.trace("Appended partial char seq of size = " + subSequence.length() +
+          " (c: " + chunk.writerIndex() + ", b: " + buffer.writerIndex() + ")");
+      }
+      return this.append(charSequence);
+    }
+
+    // we can write it, there is either enough space or we made enough space
+    chunk.ensureWritable(size);
     chunk.writeCharSequence(charSequence, charset);
+
     if (LOG.isTraceEnabled()) {
       LOG.trace("Appended char seq of size = " + charSequence.length() +
-                " (c: " + chunk.writerIndex() + ", b: " + buffer.writerIndex() + ")");
+        " (c: " + chunk.writerIndex() + ", b: " + buffer.writerIndex() + ")");
     }
     return this;
   }
@@ -189,13 +197,8 @@ public AdvisingAppendable append(CharSequence csq, int start, int end) {
 
   @Override
   public AdvisingAppendable append(char c) {
-    ensureChunkSize(1);
     char[] item = {c};
-    chunk.writeCharSequence(CharBuffer.wrap(item), charset);
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Appended char seq of size = 1 (c: " +
-                chunk.writerIndex() + ", b: " + buffer.writerIndex() + ")");
-    }
+    append(CharBuffer.wrap(item));
     return this;
   }