getDataBuffer() now releases the GIL to allow other python threads to run

while reading image data.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/exiv2wrapper.cpp b/src/exiv2wrapper.cpp
index 8ee13de..c6a94de 100644
--- a/src/exiv2wrapper.cpp
+++ b/src/exiv2wrapper.cpp
@@ -486,6 +486,12 @@ void Image::copyMetadata(Image& other, bool exif, bool iptc, bool xmp) const
 
 std::string Image::getDataBuffer() const
 {
+    std::string buffer;
+
+    // Release the GIL to allow other python threads to run
+    // while reading the image data.
+    Py_BEGIN_ALLOW_THREADS
+
     Exiv2::BasicIo& io = _image->io();
     long size = io.size();
     long pos = -1;
@@ -508,7 +514,7 @@ std::string Image::getDataBuffer() const
     // because it would be truncated after the first occurence of a null
     // character. Therefore, it has to be copied character by character.
     // First allocate the memory for the whole string...
-    std::string buffer(size, ' ');
+    buffer.resize(size, ' ');
     // ... then fill it with the raw data.
     for (unsigned long i = 0; i < size; ++i)
     {
@@ -526,6 +532,9 @@ std::string Image::getDataBuffer() const
         io.seek(pos, Exiv2::BasicIo::beg);
     }
 
+    // Re-acquire the GIL
+    Py_END_ALLOW_THREADS
+
     return buffer;
 }