[librsvg: 23/43] impl ParseToParseError for i32 instead of using an integer() function

[Federico Mena Quintero <federico src gnome org>]

commit 245f8735523f489ac8274c44d056e30b0e950c3c
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Dec 20 14:23:21 2019 -0600

    impl ParseToParseError for i32 instead of using an integer() function

 rsvg_internals/src/filters/convolve_matrix.rs | 49 +++++++++++++--------------
 rsvg_internals/src/filters/turbulence.rs      |  4 +--
 rsvg_internals/src/parsers.rs                 | 25 +++++++-------
 3 files changed, 38 insertions(+), 40 deletions(-)
---
diff --git a/rsvg_internals/src/filters/convolve_matrix.rs b/rsvg_internals/src/filters/convolve_matrix.rs
index 6c2b706f..1c24a022 100644
--- a/rsvg_internals/src/filters/convolve_matrix.rs
+++ b/rsvg_internals/src/filters/convolve_matrix.rs
@@ -7,7 +7,7 @@ use crate::drawing_ctx::DrawingCtx;
 use crate::error::*;
 use crate::node::{NodeResult, NodeTrait, RsvgNode};
 use crate::number_list::{NumberList, NumberListLength};
-use crate::parsers::{self, Parse, ParseValue};
+use crate::parsers::{self, Parse, ParseValue, ParseValueToParseError};
 use crate::property_bag::PropertyBag;
 use crate::rect::IRect;
 use crate::surface_utils::{
@@ -112,34 +112,32 @@ impl NodeTrait for FeConvolveMatrix {
         for (attr, value) in pbag.iter() {
             match attr.expanded() {
                 expanded_name!(svg "targetX") => {
-                    self.target_x = Some(
-                        parsers::integer(value)
-                            .and_then(|x| {
-                                if x >= 0 && x < self.order.0 as i32 {
-                                    Ok(x as u32)
-                                } else {
-                                    Err(ValueErrorKind::value_error(
+                    self.target_x = {
+                        let v = attr.parse_to_parse_error_and_validate(value, |v: i32| {
+                            if v >= 0 && v < self.order.0 as i32 {
+                                Ok(v)
+                            } else {
+                                Err(ValueErrorKind::value_error(
                                     "targetX must be greater or equal to zero and less than orderX",
                                 ))
-                                }
-                            })
-                            .attribute(attr)?,
-                    )
+                            }
+                        })?;
+                        Some(v as u32)
+                    }
                 }
                 expanded_name!(svg "targetY") => {
-                    self.target_y = Some(
-                        parsers::integer(value)
-                            .and_then(|x| {
-                                if x >= 0 && x < self.order.1 as i32 {
-                                    Ok(x as u32)
-                                } else {
-                                    Err(ValueErrorKind::value_error(
+                    self.target_y = {
+                        let v = attr.parse_to_parse_error_and_validate(value, |v: i32| {
+                            if v >= 0 && v < self.order.1 as i32 {
+                                Ok(v)
+                            } else {
+                                Err(ValueErrorKind::value_error(
                                     "targetY must be greater or equal to zero and less than orderY",
                                 ))
-                                }
-                            })
-                            .attribute(attr)?,
-                    )
+                            }
+                        })?;
+                        Some(v as u32)
+                    }
                 }
                 _ => (),
             }
@@ -163,8 +161,9 @@ impl NodeTrait for FeConvolveMatrix {
 
                 // #352: Parse as an unbounded list rather than exact length to prevent aborts due
                 //       to huge allocation attempts by underlying Vec::with_capacity().
-                let NumberList(v) = NumberList::parse_str_to_parse_error(value, NumberListLength::Unbounded)
-                    .attribute(attr.clone())?;
+                let NumberList(v) =
+                    NumberList::parse_str_to_parse_error(value, NumberListLength::Unbounded)
+                        .attribute(attr.clone())?;
 
                 if v.len() != number_of_elements {
                     return Err(ValueErrorKind::value_error(&format!(
diff --git a/rsvg_internals/src/filters/turbulence.rs b/rsvg_internals/src/filters/turbulence.rs
index e562f6bd..50a5b020 100644
--- a/rsvg_internals/src/filters/turbulence.rs
+++ b/rsvg_internals/src/filters/turbulence.rs
@@ -5,7 +5,7 @@ use markup5ever::{expanded_name, local_name, namespace_url, ns};
 use crate::drawing_ctx::DrawingCtx;
 use crate::error::*;
 use crate::node::{CascadedValues, NodeResult, NodeTrait, RsvgNode};
-use crate::parsers::{self, Parse, ParseValue};
+use crate::parsers::{self, Parse, ParseValue, ParseValueToParseError};
 use crate::property_bag::PropertyBag;
 use crate::surface_utils::{
     shared_surface::{SharedImageSurface, SurfaceType},
@@ -76,7 +76,7 @@ impl NodeTrait for FeTurbulence {
                         .attribute(attr)?
                 }
                 expanded_name!(svg "numOctaves") => {
-                    self.num_octaves = parsers::integer(value).attribute(attr)?
+                    self.num_octaves = attr.parse_to_parse_error(value)?;
                 }
                 // Yes, seed needs to be parsed as a number and then truncated.
                 expanded_name!(svg "seed") => {
diff --git a/rsvg_internals/src/parsers.rs b/rsvg_internals/src/parsers.rs
index 31adbd35..c96c59ed 100644
--- a/rsvg_internals/src/parsers.rs
+++ b/rsvg_internals/src/parsers.rs
@@ -153,14 +153,13 @@ pub fn number_optional_number(s: &str) -> Result<(f64, f64), ValueErrorKind> {
     }
 }
 
-// integer
-//
-// https://www.w3.org/TR/SVG11/types.html#DataTypeInteger
-pub fn integer(s: &str) -> Result<i32, ValueErrorKind> {
-    let mut input = ParserInput::new(s);
-    let mut parser = Parser::new(&mut input);
-
-    Ok(parser.expect_integer()?)
+impl ParseToParseError for i32 {
+    /// CSS integer
+    ///
+    /// https://www.w3.org/TR/SVG11/types.html#DataTypeInteger
+    fn parse_to_parse_error<'i>(parser: &mut Parser<'i, '_>) -> Result<Self, CssParseError<'i>> {
+        Ok(parser.expect_integer()?)
+    }
 }
 
 // integer-optional-integer
@@ -240,15 +239,15 @@ mod tests {
 
     #[test]
     fn parses_integer() {
-        assert_eq!(integer("1"), Ok(1));
-        assert_eq!(integer("-1"), Ok(-1));
+        assert_eq!(i32::parse_str_to_parse_error("1"), Ok(1));
+        assert_eq!(i32::parse_str_to_parse_error("-1"), Ok(-1));
     }
 
     #[test]
     fn invalid_integer() {
-        assert!(integer("").is_err());
-        assert!(integer("1x").is_err());
-        assert!(integer("1.5").is_err());
+        assert!(i32::parse_str_to_parse_error("").is_err());
+        assert!(i32::parse_str_to_parse_error("1x").is_err());
+        assert!(i32::parse_str_to_parse_error("1.5").is_err());
     }
 
     #[test]