[librsvg: 1/3] FontSizeSpec: move to a font_props.rs file

[Federico Mena Quintero <federico src gnome org>]

commit 7ae2bb3053fbbe65e032f688d3c7c1aef58f5702
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Aug 8 17:55:46 2018 -0500

    FontSizeSpec: move to a font_props.rs file
    
    We'll use this file for various types/properties that need their own
    custom parsers.

 Makefile.am                      |   1 +
 rsvg_internals/src/font_props.rs | 123 +++++++++++++++++++++++++++++++++++++++
 rsvg_internals/src/length.rs     | 112 +----------------------------------
 rsvg_internals/src/lib.rs        |   1 +
 rsvg_internals/src/state.rs      |   3 +-
 5 files changed, 128 insertions(+), 112 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 69bf4bc3..f22aef00 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -80,6 +80,7 @@ RUST_SRC =                                                    \
        rsvg_internals/src/filters/turbulence.rs                \
        rsvg_internals/src/error.rs                             \
        rsvg_internals/src/float_eq_cairo.rs                    \
+       rsvg_internals/src/font_props.rs                        \
        rsvg_internals/src/gradient.rs                          \
        rsvg_internals/src/handle.rs                            \
        rsvg_internals/src/image.rs                             \
diff --git a/rsvg_internals/src/font_props.rs b/rsvg_internals/src/font_props.rs
new file mode 100644
index 00000000..32963869
--- /dev/null
+++ b/rsvg_internals/src/font_props.rs
@@ -0,0 +1,123 @@
+use cssparser::{Parser, Token};
+
+use drawing_ctx::DrawingCtx;
+use error::*;
+use length::{Length, LengthDir, LengthUnit, POINTS_PER_INCH};
+use parsers::Parse;
+use state::ComputedValues;
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum FontSizeSpec {
+    Smaller,
+    Larger,
+    XXSmall,
+    XSmall,
+    Small,
+    Medium,
+    Large,
+    XLarge,
+    XXLarge,
+    Value(Length),
+}
+
+impl FontSizeSpec {
+    pub fn value(&self) -> Length {
+        match self {
+            FontSizeSpec::Value(s) => s.clone(),
+            _ => unreachable!(),
+        }
+    }
+
+    pub fn compute(&self, v: &ComputedValues) -> Self {
+        let compute_points = |p| 12.0 * 1.2f64.powf(p) / POINTS_PER_INCH;
+
+        let size = v.font_size.0.value();
+
+        let new_size = match self {
+            FontSizeSpec::Smaller => Length::new(size.length / 1.2, size.unit, LengthDir::Both),
+            FontSizeSpec::Larger => Length::new(size.length * 1.2, size.unit, LengthDir::Both),
+            FontSizeSpec::XXSmall => {
+                Length::new(compute_points(-3.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::XSmall => {
+                Length::new(compute_points(-2.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::Small => {
+                Length::new(compute_points(-1.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::Medium => {
+                Length::new(compute_points(0.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::Large => {
+                Length::new(compute_points(1.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::XLarge => {
+                Length::new(compute_points(2.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::XXLarge => {
+                Length::new(compute_points(3.0), LengthUnit::Inch, LengthDir::Both)
+            }
+            FontSizeSpec::Value(s) if s.unit == LengthUnit::Percent => {
+                Length::new(size.length * s.length, size.unit, LengthDir::Both)
+            }
+            FontSizeSpec::Value(s) => s.clone(),
+        };
+
+        FontSizeSpec::Value(new_size)
+    }
+
+    pub fn normalize(&self, values: &ComputedValues, draw_ctx: &DrawingCtx) -> f64 {
+        self.value().normalize(values, draw_ctx)
+    }
+}
+
+impl Parse for FontSizeSpec {
+    type Data = ();
+    type Err = AttributeError;
+
+    fn parse(parser: &mut Parser, _: Self::Data) -> Result<FontSizeSpec, ::error::AttributeError> {
+        let parser_state = parser.state();
+
+        Length::parse(parser, LengthDir::Both)
+            .and_then(|s| Ok(FontSizeSpec::Value(s)))
+            .or_else(|e| {
+                parser.reset(&parser_state);
+
+                {
+                    let token = parser.next().map_err(|_| {
+                        ::error::AttributeError::Parse(::parsers::ParseError::new("expected token"))
+                    })?;
+
+                    if let Token::Ident(ref cow) = token {
+                        match cow.as_ref() {
+                            "smaller" => return Ok(FontSizeSpec::Smaller),
+                            "larger" => return Ok(FontSizeSpec::Larger),
+                            "xx-small" => return Ok(FontSizeSpec::XXSmall),
+                            "x-small" => return Ok(FontSizeSpec::XSmall),
+                            "small" => return Ok(FontSizeSpec::Small),
+                            "medium" => return Ok(FontSizeSpec::Medium),
+                            "large" => return Ok(FontSizeSpec::Large),
+                            "x-large" => return Ok(FontSizeSpec::XLarge),
+                            "xx-large" => return Ok(FontSizeSpec::XXLarge),
+                            _ => (),
+                        };
+                    }
+                }
+
+                parser.reset(&parser_state);
+
+                Err(e)
+            })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn invalid_font_size_yields_error() {
+        assert!(is_parse_error(&FontSizeSpec::parse_str("furlong", ())));
+    }
+
+}
diff --git a/rsvg_internals/src/length.rs b/rsvg_internals/src/length.rs
index 85c3d96e..7fe2bcf4 100644
--- a/rsvg_internals/src/length.rs
+++ b/rsvg_internals/src/length.rs
@@ -40,7 +40,7 @@ impl Default for Length {
     }
 }
 
-const POINTS_PER_INCH: f64 = 72.0;
+pub const POINTS_PER_INCH: f64 = 72.0;
 const CM_PER_INCH: f64 = 2.54;
 const MM_PER_INCH: f64 = 25.4;
 const PICA_PER_INCH: f64 = 6.0;
@@ -257,111 +257,6 @@ fn viewport_percentage(x: f64, y: f64) -> f64 {
     (x * x + y * y).sqrt() / SQRT_2
 }
 
-#[derive(Debug, Copy, Clone, PartialEq)]
-pub enum FontSizeSpec {
-    Smaller,
-    Larger,
-    XXSmall,
-    XSmall,
-    Small,
-    Medium,
-    Large,
-    XLarge,
-    XXLarge,
-    Value(Length),
-}
-
-impl FontSizeSpec {
-    pub fn value(&self) -> Length {
-        match self {
-            FontSizeSpec::Value(s) => s.clone(),
-            _ => unreachable!(),
-        }
-    }
-
-    pub fn compute(&self, v: &ComputedValues) -> Self {
-        let compute_points = |p| 12.0 * 1.2f64.powf(p) / POINTS_PER_INCH;
-
-        let size = v.font_size.0.value();
-
-        let new_size = match self {
-            FontSizeSpec::Smaller => Length::new(size.length / 1.2, size.unit, LengthDir::Both),
-            FontSizeSpec::Larger => Length::new(size.length * 1.2, size.unit, LengthDir::Both),
-            FontSizeSpec::XXSmall => {
-                Length::new(compute_points(-3.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::XSmall => {
-                Length::new(compute_points(-2.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::Small => {
-                Length::new(compute_points(-1.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::Medium => {
-                Length::new(compute_points(0.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::Large => {
-                Length::new(compute_points(1.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::XLarge => {
-                Length::new(compute_points(2.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::XXLarge => {
-                Length::new(compute_points(3.0), LengthUnit::Inch, LengthDir::Both)
-            }
-            FontSizeSpec::Value(s) if s.unit == LengthUnit::Percent => {
-                Length::new(size.length * s.length, size.unit, LengthDir::Both)
-            }
-            FontSizeSpec::Value(s) => s.clone(),
-        };
-
-        FontSizeSpec::Value(new_size)
-    }
-
-    pub fn normalize(&self, values: &ComputedValues, draw_ctx: &DrawingCtx) -> f64 {
-        self.value().normalize(values, draw_ctx)
-    }
-}
-
-impl Parse for FontSizeSpec {
-    type Data = ();
-    type Err = AttributeError;
-
-    fn parse(parser: &mut Parser, _: Self::Data) -> Result<FontSizeSpec, ::error::AttributeError> {
-        let parser_state = parser.state();
-
-        Length::parse(parser, LengthDir::Both)
-            .and_then(|s| Ok(FontSizeSpec::Value(s)))
-            .or_else(|e| {
-                parser.reset(&parser_state);
-
-                {
-                    let token = parser.next().map_err(|_| {
-                        ::error::AttributeError::Parse(::parsers::ParseError::new("expected token"))
-                    })?;
-
-                    if let Token::Ident(ref cow) = token {
-                        match cow.as_ref() {
-                            "smaller" => return Ok(FontSizeSpec::Smaller),
-                            "larger" => return Ok(FontSizeSpec::Larger),
-                            "xx-small" => return Ok(FontSizeSpec::XXSmall),
-                            "x-small" => return Ok(FontSizeSpec::XSmall),
-                            "small" => return Ok(FontSizeSpec::Small),
-                            "medium" => return Ok(FontSizeSpec::Medium),
-                            "large" => return Ok(FontSizeSpec::Large),
-                            "x-large" => return Ok(FontSizeSpec::XLarge),
-                            "xx-large" => return Ok(FontSizeSpec::XXLarge),
-                            _ => (),
-                        };
-                    }
-                }
-
-                parser.reset(&parser_state);
-
-                Err(e)
-            })
-    }
-}
-
 #[derive(Debug, PartialEq, Clone)]
 pub enum Dasharray {
     None,
@@ -510,11 +405,6 @@ mod tests {
         );
     }
 
-    #[test]
-    fn invalid_font_size_yields_error() {
-        assert!(is_parse_error(&FontSizeSpec::parse_str("furlong", ())));
-    }
-
     fn parse_dash_array_str(s: &str) -> Result<Dasharray, AttributeError> {
         Dasharray::parse_str(s, ())
     }
diff --git a/rsvg_internals/src/lib.rs b/rsvg_internals/src/lib.rs
index 62e9c2dd..b2a8610c 100644
--- a/rsvg_internals/src/lib.rs
+++ b/rsvg_internals/src/lib.rs
@@ -91,6 +91,7 @@ mod defs;
 mod drawing_ctx;
 mod error;
 pub mod filters;
+mod font_props;
 mod gradient;
 mod handle;
 mod image;
diff --git a/rsvg_internals/src/state.rs b/rsvg_internals/src/state.rs
index 767628bd..78c40fb8 100644
--- a/rsvg_internals/src/state.rs
+++ b/rsvg_internals/src/state.rs
@@ -8,9 +8,10 @@ use std::str::FromStr;
 
 use attributes::Attribute;
 use error::*;
+use font_props::FontSizeSpec;
 use handle::RsvgHandle;
 use iri::IRI;
-use length::{Dasharray, FontSizeSpec, Length, LengthDir, LengthUnit};
+use length::{Dasharray, Length, LengthDir, LengthUnit};
 use node::RsvgNode;
 use paint_server::PaintServer;
 use parsers::{Parse, ParseError};