Another refactoring in links.rs (#1001)

* Extract the concept of a link having a range or anchor specified

So that other kinds of links can use this concept too.

* Extract a function for parsing range or anchor

src/preprocess/links.rs

@@ -102,11 +102,16 @@ where
 #[derive(PartialEq, Debug, Clone)]
 enum LinkType<'a> {
     Escaped,
-    IncludeRange(PathBuf, LineRange),
+    Include(PathBuf, RangeOrAnchor),
-    IncludeAnchor(PathBuf, String),
     Playpen(PathBuf, Vec<&'a str>),
 }
 
+#[derive(PartialEq, Debug, Clone)]
+enum RangeOrAnchor {
+    Range(LineRange),
+    Anchor(String),
+}
+
 // A range of lines specified with some include directive.
 #[derive(PartialEq, Debug, Clone)]
 enum LineRange {
@@ -165,8 +170,7 @@ impl<'a> LinkType<'a> {
         let base = base.as_ref();
         match self {
             LinkType::Escaped => None,
-            LinkType::IncludeRange(p, _) => Some(return_relative_path(base, &p)),
+            LinkType::Include(p, _) => Some(return_relative_path(base, &p)),
-            LinkType::IncludeAnchor(p, _) => Some(return_relative_path(base, &p)),
             LinkType::Playpen(p, _) => Some(return_relative_path(base, &p)),
         }
     }
@@ -179,9 +183,8 @@ fn return_relative_path<P: AsRef<Path>>(base: P, relative: P) -> PathBuf {
         .to_path_buf()
 }
 
-fn parse_include_path(path: &str) -> LinkType<'static> {
+fn parse_range_or_anchor(parts: Option<&str>) -> RangeOrAnchor {
-    let mut parts = path.splitn(4, ':').fuse();
+    let mut parts = parts.unwrap_or("").splitn(3, ':').fuse();
-    let path = parts.next().unwrap().into();
 
     let next_element = parts.next();
     let start = if let Some(value) = next_element.and_then(|s| s.parse::<usize>().ok()) {
@@ -190,7 +193,7 @@ fn parse_include_path(path: &str) -> LinkType<'static> {
     } else if let Some("") = next_element {
         None
     } else if let Some(anchor) = next_element {
-        return LinkType::IncludeAnchor(path, String::from(anchor));
+        return RangeOrAnchor::Anchor(String::from(anchor));
     } else {
         None
     };
@@ -202,16 +205,23 @@ fn parse_include_path(path: &str) -> LinkType<'static> {
     let end = end.map(|s| s.parse::<usize>());
 
     match (start, end) {
-        (Some(start), Some(Ok(end))) => LinkType::IncludeRange(path, LineRange::from(start..end)),
+        (Some(start), Some(Ok(end))) => RangeOrAnchor::Range(LineRange::from(start..end)),
-        (Some(start), Some(Err(_))) => LinkType::IncludeRange(path, LineRange::from(start..)),
+        (Some(start), Some(Err(_))) => RangeOrAnchor::Range(LineRange::from(start..)),
-        (Some(start), None) => LinkType::IncludeRange(path, LineRange::from(start..start + 1)),
+        (Some(start), None) => RangeOrAnchor::Range(LineRange::from(start..start + 1)),
-        (None, Some(Ok(end))) => LinkType::IncludeRange(path, LineRange::from(..end)),
+        (None, Some(Ok(end))) => RangeOrAnchor::Range(LineRange::from(..end)),
-        (None, None) | (None, Some(Err(_))) => {
+        (None, None) | (None, Some(Err(_))) => RangeOrAnchor::Range(LineRange::from(RangeFull)),
-            LinkType::IncludeRange(path, LineRange::from(RangeFull))
-        }
     }
 }
 
+fn parse_include_path(path: &str) -> LinkType<'static> {
+    let mut parts = path.splitn(2, ':');
+
+    let path = parts.next().unwrap().into();
+    let range_or_anchor = parse_range_or_anchor(parts.next());
+
+    LinkType::Include(path, range_or_anchor)
+}
+
 #[derive(PartialEq, Debug, Clone)]
 struct Link<'a> {
     start_index: usize,
@@ -255,24 +265,14 @@ impl<'a> Link<'a> {
         match self.link_type {
             // omit the escape char
             LinkType::Escaped => Ok((&self.link_text[1..]).to_owned()),
-            LinkType::IncludeRange(ref pat, ref range) => {
+            LinkType::Include(ref pat, ref range_or_anchor) => {
                 let target = base.join(pat);
 
                 fs::read_to_string(&target)
-                    .map(|s| take_lines(&s, range.clone()))
+                    .map(|s| match range_or_anchor {
-                    .chain_err(|| {
+                        RangeOrAnchor::Range(range) => take_lines(&s, range.clone()),
-                        format!(
+                        RangeOrAnchor::Anchor(anchor) => take_anchored_lines(&s, anchor),
-                            "Could not read file for link {} ({})",
-                            self.link_text,
-                            target.display(),
-                        )
                     })
-            }
-            LinkType::IncludeAnchor(ref pat, ref anchor) => {
-                let target = base.join(pat);
-
-                fs::read_to_string(&target)
-                    .map(|s| take_anchored_lines(&s, anchor))
                     .chain_err(|| {
                         format!(
                             "Could not read file for link {} ({})",
@@ -419,7 +419,10 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 48,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(9..20)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(9..20))
+                ),
                 link_text: "{{#include file.rs:10:20}}",
             }]
         );
@@ -435,7 +438,10 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 45,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(9..10)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(9..10))
+                ),
                 link_text: "{{#include file.rs:10}}",
             }]
         );
@@ -451,7 +457,10 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 46,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(9..)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(9..))
+                ),
                 link_text: "{{#include file.rs:10:}}",
             }]
         );
@@ -467,7 +476,10 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 46,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(..20)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(..20))
+                ),
                 link_text: "{{#include file.rs::20}}",
             }]
         );
@@ -483,7 +495,10 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 44,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(..)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(..))
+                ),
                 link_text: "{{#include file.rs::}}",
             }]
         );
@@ -499,7 +514,10 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 42,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(..)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(..))
+                ),
                 link_text: "{{#include file.rs}}",
             }]
         );
@@ -515,9 +533,9 @@ mod tests {
             vec![Link {
                 start_index: 22,
                 end_index: 49,
-                link_type: LinkType::IncludeAnchor(
+                link_type: LinkType::Include(
                     PathBuf::from("file.rs"),
-                    String::from("anchor")
+                    RangeOrAnchor::Anchor(String::from("anchor"))
                 ),
                 link_text: "{{#include file.rs:anchor}}",
             }]
@@ -585,7 +603,10 @@ mod tests {
             Link {
                 start_index: 38,
                 end_index: 58,
-                link_type: LinkType::IncludeRange(PathBuf::from("file.rs"), LineRange::from(..)),
+                link_type: LinkType::Include(
+                    PathBuf::from("file.rs"),
+                    RangeOrAnchor::Range(LineRange::from(..))
+                ),
                 link_text: "{{#include file.rs}}",
             }
         );
@@ -617,7 +638,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(RangeFull))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(RangeFull))
+            )
         );
     }
 
@@ -626,7 +650,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(RangeFull))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(RangeFull))
+            )
         );
     }
 
@@ -635,7 +662,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary::");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(RangeFull))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(RangeFull))
+            )
         );
     }
 
@@ -644,7 +674,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary::NaN");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(RangeFull))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(RangeFull))
+            )
         );
     }
 
@@ -653,7 +686,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:5");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(4..5))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(4..5))
+            )
         );
     }
 
@@ -662,7 +698,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:1");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(0..1))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(0..1))
+            )
         );
     }
 
@@ -671,7 +710,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:0");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(0..1))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(0..1))
+            )
         );
     }
 
@@ -680,7 +722,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:5:");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(4..))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(4..))
+            )
         );
     }
 
@@ -689,7 +734,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:5:NaN");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(4..))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(4..))
+            )
         );
     }
 
@@ -698,7 +746,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary::5");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(..5))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(..5))
+            )
         );
     }
 
@@ -707,7 +758,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:5:10");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(4..10))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(4..10))
+            )
         );
     }
 
@@ -716,7 +770,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:-5");
         assert_eq!(
             link_type,
-            LinkType::IncludeAnchor(PathBuf::from("arbitrary"), "-5".to_string())
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Anchor("-5".to_string())
+            )
         );
     }
 
@@ -725,7 +782,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:-5.7");
         assert_eq!(
             link_type,
-            LinkType::IncludeAnchor(PathBuf::from("arbitrary"), "-5.7".to_string())
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Anchor("-5.7".to_string())
+            )
         );
     }
 
@@ -734,7 +794,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:some-anchor:this-gets-ignored");
         assert_eq!(
             link_type,
-            LinkType::IncludeAnchor(PathBuf::from("arbitrary"), "some-anchor".to_string())
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Anchor("some-anchor".to_string())
+            )
         );
     }
 
@@ -743,7 +806,10 @@ mod tests {
         let link_type = parse_include_path("arbitrary:5:10:17:anything:");
         assert_eq!(
             link_type,
-            LinkType::IncludeRange(PathBuf::from("arbitrary"), LineRange::from(4..10))
+            LinkType::Include(
+                PathBuf::from("arbitrary"),
+                RangeOrAnchor::Range(LineRange::from(4..10))
+            )
         );
     }
 }