mxfreader: Don't immediately log essence read errors

Set the the MXF reader's mReadErrorMessage when less essence data is
read from a file than was requested, but don't log the error.
This avoids it being logged when reading a growing file where a later
attempt succeeds.

Note that this doesn't prevent non-essence read errors, e.g other KLVs.

include/bmx/BMXException.h

@@ -51,6 +51,14 @@
             BMX_EXCEPTION(("'%s' check failed", #cond));    \
     } while (0)
 
+#define BMX_CHECK_NOLOG(cond)                                                       \
+    do {                                                                            \
+        if (!(cond)) {                                                              \
+            throw BMXException(                                                     \
+                "'%s' check failed near %s:%d", #cond, __FILENAME__, __LINE__);     \
+        }                                                                           \
+    } while (0)
+
 #define BMX_CHECK_M(cond, err)      \
     do {                            \
         if (!(cond))                \

src/mxf_reader/EssenceReader.cpp

@@ -529,7 +529,7 @@ uint32_t EssenceReader::ReadClipWrappedSamples(uint32_t num_samples)
             frame->Grow((uint32_t)size);
             uint32_t num_read = mFile->read(frame->GetBytesAvailable(), (uint32_t)size);
             current_file_position += num_read;
-            BMX_CHECK(num_read == size);
+            BMX_CHECK_NOLOG(num_read == size);
 
             size -= mImageEndOffset;
             if (mImageStartOffset > 0) {
@@ -638,7 +638,7 @@ uint32_t EssenceReader::ReadFrameWrappedSamples(uint32_t num_samples)
                     if (!mParseOnly)
                     {
                         uint32_t num_read = mFile->read(frame->GetBytesAvailable(), (uint32_t)len);
-                        BMX_CHECK(num_read == len);
+                        BMX_CHECK_NOLOG(num_read == len);
                     } else {
                         mFile->skip(len);
                     }

test/growing_file/growing_file.md5

@@ -1 +1 @@
-2c0703daa26c571738c6f313cfd2b054
+aa99fd8e8e058b07af7db303dc58653c