Fixed situation where an Error with a confusing message was thrown. Added BasicIo::path(). Further code and doc clean-up.

src/basicio.cpp

@@ -163,7 +163,7 @@ namespace Exiv2 {
                 throw Error(10, path_, "w+b", strError());
             }
             if (src.open() != 0) {
-                throw Error(9, strError());
+                throw Error(9, src.path(), strError());
             }
             write(src);
             src.close();
@@ -305,6 +305,10 @@ namespace Exiv2 {
         return feof(fp_) != 0;
     }
 
+    std::string FileIo::path() const
+    {
+        return path_;
+    }
 
     MemIo::MemIo(const byte* data, long size)
     {
@@ -349,7 +353,9 @@ namespace Exiv2 {
             // Generic reopen to reset position to start
             data_.clear();
             idx_ = 0;
-            if (src.open() != 0) throw Error(9, strError());
+            if (src.open() != 0) {
+                throw Error(9, src.path(), strError());
+            }
             write(src);
             src.close();    
         }
@@ -461,4 +467,9 @@ namespace Exiv2 {
         return idx_ == data_.size();
     }
 
+    std::string MemIo::path() const
+    {
+        return "MemIo";
+    }
+
 }                                       // namespace Exiv2

src/basicio.hpp

@@ -194,6 +194,12 @@ namespace Exiv2 {
         virtual int error() const = 0;
         //!Returns true if the IO position has reach the end, otherwise false.
         virtual bool eof() const = 0;
+        /*!
+          @brief Return the path to the IO resource. Often used to form
+              comprehensive error messages where only a BasicIo instance is
+              available.
+         */
+        virtual std::string path() const =0;
         /*!
           @brief Returns a temporary data storage location. This is often
               needed to rewrite an IO source. 
@@ -404,12 +410,14 @@ namespace Exiv2 {
                  -1 if failure;
          */
         virtual long size() const;
-        //!Returns true if the file is open, otherwise false.
+        //! Returns true if the file is open, otherwise false.
         virtual bool isopen() const;
-        //!Returns 0 if the file is in a valid state, otherwise nonzero.
+        //! Returns 0 if the file is in a valid state, otherwise nonzero.
         virtual int error() const;
-        //!Returns true if the file position has reach the end, otherwise false.
+        //! Returns true if the file position has reach the end, otherwise false.
         virtual bool eof() const;
+        //! Returns the path of the file
+        virtual std::string path() const;
         /*!
           @brief Returns a temporary data storage location. The actual type
               returned depends upon the size of the file represented a FileIo
@@ -590,6 +598,8 @@ namespace Exiv2 {
         virtual int error() const;
         //!Returns true if the IO position has reach the end, otherwise false.
         virtual bool eof() const;
+        //! Returns a dummy path, indicating that memory access is used
+        virtual std::string path() const;
         /*!
           @brief Returns a temporary data storage location. Currently returns
               an empty MemIo object, but callers should not rely on this

src/error.cpp

@@ -52,7 +52,7 @@ namespace Exiv2 {
         ErrMsg(  6, "Invalid key `%1'"), // %1=key
         ErrMsg(  7, "Invalid tag name or ifdId `%1', ifdId %2"), // %1=tag name, %2=ifdId
         ErrMsg(  8, "Value not set"), 
-        ErrMsg(  9, "Failed to open the data source: %1"), // %1=strerror
+        ErrMsg(  9, "%1: Failed to open the data source: %2"), // %1=path, %2=strerror
         ErrMsg( 10, "%1: Failed to open file (%2): %3"), // %1=path, %2=mode, %3=strerror
         ErrMsg( 11, "%1: The file contains data of an unknown image type"), // %1=path
         ErrMsg( 12, "The memory contains data of an unknown image type"),

src/image.cpp

@@ -115,7 +115,7 @@ namespace Exiv2 {
     Image::AutoPtr ImageFactory::open(const std::string& path)
     {
         BasicIo::AutoPtr io(new FileIo(path));
-        Image::AutoPtr image(open(io));
+        Image::AutoPtr image = open(io); // may throw
         if (image.get() == 0) throw Error(11, path);
         return image;
     }
@@ -123,20 +123,20 @@ namespace Exiv2 {
     Image::AutoPtr ImageFactory::open(const byte* data, long size)
     {
         BasicIo::AutoPtr io(new MemIo(data, size));
-        Image::AutoPtr image(open(io));
+        Image::AutoPtr image = open(io); // may throw
         if (image.get() == 0) throw Error(12);
         return image;
     }
 
     Image::AutoPtr ImageFactory::open(BasicIo::AutoPtr io)
     {
+        if (io->open() != 0) {
+            throw Error(9, io->path(), strError());
+        }
         Image::AutoPtr image;
-        if (io->open() != 0) return image;
-        IoCloser closer(*io);
         Registry::const_iterator b = registry_->begin();
         Registry::const_iterator e = registry_->end();
-        for (Registry::const_iterator i = b; i != e; ++i)
-        {
+        for (Registry::const_iterator i = b; i != e; ++i) {
             if (i->second.isThisType(*io, false)) {
                 image = i->second.newInstance(io, false);
                 break;
@@ -155,7 +155,7 @@ namespace Exiv2 {
         }
         fileIo->close();
         BasicIo::AutoPtr io(fileIo);
-        Image::AutoPtr image(create(type, io));
+        Image::AutoPtr image = create(type, io);
         if (image.get() == 0) throw Error(13, type);
         return image;
     }
@@ -163,7 +163,7 @@ namespace Exiv2 {
     Image::AutoPtr ImageFactory::create(Image::Type type)
     {
         BasicIo::AutoPtr io(new MemIo);
-        Image::AutoPtr image(create(type, io));
+        Image::AutoPtr image = create(type, io);
         if (image.get() == 0) throw Error(13, type);
         return image;
     }

src/image.hpp

@@ -302,13 +302,15 @@ namespace Exiv2 {
               (re)opened by this method. 
           @param io An auto-pointer that owns a BasicIo instance that provides
               image data. The contents of the image data are tested to determine
-              the type. \b Important: This method takes ownership of the passed
+              the type. 
+          @note This method takes ownership of the passed
               in BasicIo instance through the auto-pointer. Callers should not
               continue to use the BasicIo instance after it is passed to this method.
-              Use theImage::io() method to get a temporary reference.
+              Use the Image::io() method to get a temporary reference.
           @return An auto-pointer that owns an Image instance whose type 
               matches that of the \em io data. If no image type could be
               determined, the pointer is 0.
+          @throw Error If opening the BasicIo fails
          */
         static Image::AutoPtr open(BasicIo::AutoPtr io);
         /*!
@@ -336,11 +338,11 @@ namespace Exiv2 {
               contains data, it will be overwritten.
           @param type Type of the image to be created.
           @param io An auto-pointer that owns a BasicIo instance that will
-              be written to when creating a new image. \b Important: This
-              method takes ownership of the passed in BasicIo instance through
-              the auto-pointer. Callers should not continue to use the BasicIo
-              instance after it is passed to this method.  Use theImage::io()
-              method to get a temporary reference.
+              be written to when creating a new image. 
+          @note This method takes ownership of the passed in BasicIo instance
+              through the auto-pointer. Callers should not continue to use the 
+              BasicIo instance after it is passed to this method.  Use the 
+              Image::io() method to get a temporary reference.
           @return An auto-pointer that owns an Image instance of the requested
               type. If the image type is not supported, the pointer is 0.
          */

src/iotest.cpp

@@ -58,7 +58,7 @@ try {
 
     FileIo fileIn(argv[1]);
     if (fileIn.open() != 0) {
-        throw Error(9, strError());
+        throw Error(9, fileIn.path(), strError());
     }
 
     FileIo fileOut1(argv[2]);
@@ -139,7 +139,7 @@ int WriteReadSeek(BasicIo &io)
     const long len2 = (long)strlen(tester2) + 1;
 
     if (io.open() != 0) {
-        throw Error(9, strError());
+        throw Error(9, io.path(), strError());
     }
     IoCloser closer(io);
     if (io.write((byte*)tester1, len1) != len1) {
@@ -202,7 +202,7 @@ int WriteReadSeek(BasicIo &io)
 
     // open should seek to beginning
     if (io.open() != 0)  {
-        throw Error(9, strError());
+        throw Error(9, io.path(), strError());
     }
     memset(buf, -1, sizeof(buf));
     if (io.read(buf, sizeof(buf)) != insert + len2) {

src/jpgimage.cpp

@@ -86,7 +86,7 @@ namespace Exiv2 {
         : io_(io)
     {
         if (create) {
-            initImage(initData, dataSize); // may throw
+            initImage(initData, dataSize);
         }
     }
 
@@ -171,7 +171,7 @@ namespace Exiv2 {
     void JpegBase::readMetadata()
     {
         if (io_->open() != 0) {
-            throw Error(9, strError());
+            throw Error(9, io_->path(), strError());
         }
         IoCloser closer(*io_);
         // Ensure that this is the correct image type
@@ -298,7 +298,9 @@ namespace Exiv2 {
 
     void JpegBase::writeMetadata()
     {
-        if (io_->open() != 0) throw Error(9, strError());
+        if (io_->open() != 0) {
+            throw Error(9, io_->path(), strError());
+        }
         IoCloser closer(*io_);
         BasicIo::AutoPtr tempIo(io_->temporary()); // may throw
         assert (tempIo.get() != 0);
@@ -574,13 +576,7 @@ namespace Exiv2 {
 
     Image::AutoPtr newJpegInstance(BasicIo::AutoPtr io, bool create)
     {
-        Image::AutoPtr image;
-        if (create) {
-            image = Image::AutoPtr(new JpegImage(io, true));
-        }
-        else {
-            image = Image::AutoPtr(new JpegImage(io, false));
-        }
+        Image::AutoPtr image = Image::AutoPtr(new JpegImage(io, create));
         if (!image->good()) {
             image.reset();
         }
@@ -654,8 +650,8 @@ namespace Exiv2 {
         iIo.read(tmpBuf, 7);
         if (iIo.error() || iIo.eof()) return false;
 
-        if (0xff!=tmpBuf[0] || 0x01!=tmpBuf[1] || 
-                    memcmp(tmpBuf + 2, ExvImage::exiv2Id_, 5) != 0) {
+        if (   0xff != tmpBuf[0] || 0x01 != tmpBuf[1] 
+            || memcmp(tmpBuf + 2, ExvImage::exiv2Id_, 5) != 0) {
             result = false;
         }
         if (!advance || !result ) iIo.seek(-7, BasicIo::cur);

src/jpgimage.hpp

@@ -235,9 +235,7 @@ namespace Exiv2 {
                 writing all buffered metadata to the provided BasicIo. 
           @param oIo BasicIo instance to write to (a temporary location).
 
-          @throw Error if reading from input file failed, the output file
-                can not be written to, or the input file does not contain 
-                a valid image.
+          @return 4 if opening or writing to the associated BasicIo fails
          */
         void doWriteMetadata(BasicIo& oIo);