IOFile: did not properly set m_mode upon open failure. (#2187)

One consequence is that format readers or writers that relied on
IOFile (such as PNG and JPEG) would not properly notice certain I/O
errors.

This failure of JPEG masked a minor bug in the JPEG reader where we
could destroy the compressor that had never been created (crashing
inside jpeg library).

src/jpeg.imageio/jpeg_pvt.h

@@ -102,10 +102,11 @@ class JpgInput final : public ImageInput {
 private:
     FILE* m_fd;
     std::string m_filename;
-    int m_next_scanline;  // Which scanline is the next to read?
-    bool m_raw;           // Read raw coefficients, not scanlines
-    bool m_cmyk;          // The input file is cmyk
-    bool m_fatalerr;      // JPEG reader hit a fatal error
+    int m_next_scanline;   // Which scanline is the next to read?
+    bool m_raw;            // Read raw coefficients, not scanlines
+    bool m_cmyk;           // The input file is cmyk
+    bool m_fatalerr;       // JPEG reader hit a fatal error
+    bool m_decomp_create;  // Have we created the decompressor?
     struct jpeg_decompress_struct m_cinfo;
     my_error_mgr m_jerr;
     jvirt_barray_ptr* m_coeffs;
@@ -119,6 +120,7 @@ class JpgInput final : public ImageInput {
         m_raw           = false;
         m_cmyk          = false;
         m_fatalerr      = false;
+        m_decomp_create = false;
         m_coeffs        = NULL;
         m_jerr.jpginput = this;
         m_io            = nullptr;

src/jpeg.imageio/jpeginput.cpp

@@ -255,6 +255,7 @@ JpgInput::open(const std::string& name, ImageSpec& newspec)
 
     // initialize decompressor
     jpeg_create_decompress(&m_cinfo);
+    m_decomp_create = true;
     // specify the data source
     if (!strcmp(m_io->proxytype(), "file")) {
         auto fd = ((Filesystem::IOFile*)m_io)->handle();
@@ -511,7 +512,9 @@ JpgInput::close()
 {
     if (m_io) {
         // unnecessary?  jpeg_abort_decompress (&m_cinfo);
-        jpeg_destroy_decompress(&m_cinfo);
+        if (m_decomp_create)
+            jpeg_destroy_decompress(&m_cinfo);
+        m_decomp_create = false;
         close_file();
     }
     init();  // Reset to initial state

src/libutil/filesystem.cpp

@@ -922,19 +922,20 @@ Filesystem::IOFile::IOFile(string_view filename, Mode mode)
 {
     // Call Filesystem::fopen since it handles UTF-8 file paths on Windows,
     // which std fopen does not.
-    m_file = Filesystem::fopen(m_filename.c_str(), mode == Write ? "wb" : "rb");
+    m_file = Filesystem::fopen(m_filename.c_str(),
+                               m_mode == Write ? "wb" : "rb");
     if (!m_file)
-        mode = Closed;
+        m_mode = Closed;
     m_auto_close = true;
-    if (mode == Read)
+    if (m_mode == Read)
         m_size = Filesystem::file_size(filename);
 }
 
 Filesystem::IOFile::IOFile(FILE* file, Mode mode)
     : IOProxy("", mode)
     , m_file(file)
 {
-    if (mode == Read) {
+    if (m_mode == Read) {
         m_pos = ftell(m_file);           // save old position
         fseek(m_file, 0, SEEK_END);      // seek to end
         m_size = size_t(ftell(m_file));  // size is end position

testsuite/python-imageinput/src/test_imageinput.py

@@ -4,7 +4,8 @@
 import OpenImageIO as oiio
 import os
 
-OIIO_TESTSUITE_IMAGEDIR = os.environ['OIIO_TESTSUITE_IMAGEDIR']
+OIIO_TESTSUITE_IMAGEDIR = os.environ.get('OIIO_TESTSUITE_IMAGEDIR',
+                                         '../../../../../oiio-images')
 
 # Print the contents of an ImageSpec
 def print_imagespec (spec, subimage=0, mip=0, msg="") :