[gxml] Document.vala: add error handling to IO operations

[Richard Hans Schwarting <rschwart src gnome org>]

commit fe761d0a47599f104ce590ee64714e1fc0a8b1cb
Author: Richard Schwarting <aquarichy gmail com>
Date:   Mon Oct 14 02:48:40 2013 -0400

    Document.vala: add error handling to IO operations

 gxml/Document.vala |   63 ++++++++++++++++++++++++++++++++++++++--------------
 1 files changed, 46 insertions(+), 17 deletions(-)
---
diff --git a/gxml/Document.vala b/gxml/Document.vala
index 760401f..17878d3 100644
--- a/gxml/Document.vala
+++ b/gxml/Document.vala
@@ -397,8 +397,8 @@ namespace GXml {
                /**
                 * Creates a Document from the File fin.
                 */
-               public Document.from_gfile (File fin, Cancellable? can = null) {
-                       // TODO: accept cancellable
+               public Document.from_gfile (File fin, Cancellable? can = null) throws GLib.Error {
+                       // TODO: actually handle cancellable
                        InputStream instream;
 
                        try {
@@ -407,21 +407,26 @@ namespace GXml {
                                instream.close ();
                        } catch (GLib.Error e) {
                                GXml.warning (DomException.INVALID_DOC, "Could not load document from GFile: 
%s".printf (e.message));
+                               throw e;
                        }
                }
                /**
                 * Creates a Document from data provided through the InputStream instream.
                 */
-               public Document.from_stream (InputStream instream, Cancellable? can = null) {
-                       // TODO: accept Cancellable
-                       // Cancellable can = new Cancellable ();
+               public Document.from_stream (InputStream instream, Cancellable? can = null) throws GXml.Error 
{
                        InputStreamBox box = { instream, can };
                        Xml.Doc *doc;
                        Xml.TextReader reader = new Xml.TextReader.for_io ((Xml.InputReadCallback)_ioread,
                                                                           (Xml.InputCloseCallback)_ioinclose,
                                                                           &box, "", null, 0);
-                       reader.read ();
-                       reader.expand ();
+                       if (-1 == reader.read ()) {
+                               throw new GXml.Error.PARSER ("Error reading from stream");
+                               // TODO: see if we can pull an error from libxml2 somewhere
+                       }
+                       if (null == reader.expand ()) {
+                               throw new GXml.Error.PARSER ("Error expanding from stream");
+                               // TODO: see if we can pull an error from libxml2 somewhere
+                       }
                        doc = reader.current_doc ();
                        reader.close ();
 
@@ -475,11 +480,19 @@ namespace GXml {
                 * Saves a Document to the file at path file_path
                 */
                // TODO: is this a simple Unix file path, or does libxml2 do networks, too?
-               public void save_to_path (string file_path) {
+               public void save_to_path (string file_path) throws GXml.Error {
+                       int ret;
+
                        sync_dirty_elements ();
 
                        // TODO: change this to a GIO file so we can save to in a cool way
-                       this.xmldoc->save_file (file_path);
+
+                       ret = this.xmldoc->save_file (file_path);
+
+                       if (ret == -1) {
+                               // TODO: use xmlGetLastError to get the real error message
+                               throw new GXml.Error.WRITER ("Failed to write file to path '%s'".printf 
(file_path));
+                       }
                }
 
                /* TODO: consider adding a save_to_file, but then we
@@ -490,18 +503,34 @@ namespace GXml {
                /**
                 * Saves a Document to the OutputStream outstream.
                 */
-               public void save_to_stream (OutputStream outstream, Cancellable? can = null) {
+               public void save_to_stream (OutputStream outstream, Cancellable? can = null) throws 
GXml.Error {
                        OutputStreamBox box = { outstream, can };
+                       int ret;
 
                        sync_dirty_elements ();
 
-                       // TODO: make sure libxml2's vapi gets patched
-                       Xml.SaveCtxt *ctxt = new Xml.SaveCtxt.to_io ((Xml.OutputWriteCallback)_iowrite,
-                                                                    (Xml.OutputCloseCallback)_iooutclose,
-                                                                    &box, null, 0);
-                       ctxt->save_doc (this.xmldoc);
-                       ctxt->flush ();
-                       ctxt->close ();
+                       /* TODO: provide Cancellable as user data and let these check it
+                                so we can actually be interruptible */
+                       Xml.SaveCtxt *ctxt;
+                       ctxt = new Xml.SaveCtxt.to_io ((Xml.OutputWriteCallback)_iowrite,
+                                                      (Xml.OutputCloseCallback)_iooutclose,
+                                                      &box, null, 0);
+                       if (ctxt == null) {
+                               throw new GXml.Error.WRITER ("Failed to create serialization context when 
saving to stream");
+                       }
+                       
+                       ret = ctxt->save_doc (this.xmldoc);
+                       if (ret == -1) {
+                               throw new GXml.Error.WRITER ("Failed to save document");
+                       }
+                       ret = ctxt->flush ();
+                       if (ret == -1) {
+                               throw new GXml.Error.WRITER ("Failed to flush remainder of document when 
saving to stream");
+                       }
+                       ret = ctxt->close ();
+                       if (ret == -1) {
+                               throw new GXml.Error.WRITER ("Failed to close saving context when saving to 
stream");
+                       }
                }
 
                /* Public Methods */