[librsvg: 26/32] Replace LoadingError::Glib(gerror) with LoadingError::Io(String)

[Federico Mena Quintero <federico src gnome org>]

commit d76aba8f5d4f54f4278be8d34fb250fba254d6ec
Author: Federico Mena Quintero <federico gnome org>
Date:   Thu Dec 3 14:32:01 2020 -0600

    Replace LoadingError::Glib(gerror) with LoadingError::Io(String)
    
    This is not ideal; not all Glib errors are I/O errors, but we don't do
    anything to distinguish them elsewhere.
    
    It may make sense to move to a Box<dyn Error> at some point.

 src/error.rs         | 12 +++++++-----
 src/xml/mod.rs       |  2 +-
 src/xml/xml2_load.rs |  2 +-
 3 files changed, 9 insertions(+), 7 deletions(-)
---
diff --git a/src/error.rs b/src/error.rs
index 249ed694..65902b82 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -337,8 +337,8 @@ pub enum LoadingError {
     /// There is no `<svg>` root element in the XML.
     NoSvgRoot,
 
-    /// Generally an I/O error, or another error from GIO.
-    Glib(glib::Error),
+    /// I/O error.
+    Io(String),
 
     /// A particular implementation-defined limit was exceeded.
     LimitExceeded(String),
@@ -357,7 +357,7 @@ impl fmt::Display for LoadingError {
             LoadingError::BadUrl => write!(f, "invalid URL"),
             LoadingError::BadCss => write!(f, "invalid CSS"),
             LoadingError::NoSvgRoot => write!(f, "XML does not have <svg> root"),
-            LoadingError::Glib(ref e) => e.fmt(f),
+            LoadingError::Io(ref s) => write!(f, "I/O error: {}", s),
             LoadingError::LimitExceeded(ref s) => write!(f, "limit exceeded: {}", s),
             LoadingError::Other(ref s) => write!(f, "{}", s),
         }
@@ -366,7 +366,9 @@ impl fmt::Display for LoadingError {
 
 impl From<glib::Error> for LoadingError {
     fn from(e: glib::Error) -> LoadingError {
-        LoadingError::Glib(e)
+        // FIXME: this is somewhat fishy; not all GError are I/O errors, but in librsvg
+        // most GError do come from gio.  Some come from GdkPixbufLoader, though.
+        LoadingError::Io(format!("{}", e))
     }
 }
 
@@ -374,7 +376,7 @@ impl From<IoError> for LoadingError {
     fn from(e: IoError) -> LoadingError {
         match e {
             IoError::BadDataUrl => LoadingError::BadUrl,
-            IoError::Glib(e) => LoadingError::Glib(e),
+            IoError::Glib(e) => LoadingError::Io(format!("{}", e)),
         }
     }
 }
diff --git a/src/xml/mod.rs b/src/xml/mod.rs
index 89f4e899..a7c125de 100644
--- a/src/xml/mod.rs
+++ b/src/xml/mod.rs
@@ -561,7 +561,7 @@ impl XmlState {
 
         // FIXME: pass a cancellable
         self.parse_from_stream(&stream, None).map_err(|e| match e {
-            LoadingError::Glib(_) => AcquireError::ResourceError,
+            LoadingError::Io(_) => AcquireError::ResourceError,
             LoadingError::XmlParseError(s) => AcquireError::FatalError(s),
             _ => AcquireError::FatalError(String::from("unknown error")),
         })
diff --git a/src/xml/xml2_load.rs b/src/xml/xml2_load.rs
index 3954fcf9..10ecf712 100644
--- a/src/xml/xml2_load.rs
+++ b/src/xml/xml2_load.rs
@@ -457,7 +457,7 @@ impl Xml2Parser {
             let io_error = err_ref.take();
 
             if let Some(io_error) = io_error {
-                Err(LoadingError::Glib(io_error))
+                Err(LoadingError::from(io_error))
             } else if !xml_parse_success {
                 let xerr = xmlCtxtGetLastError(parser as *mut _);
                 let msg = xml2_error_to_string(xerr);