Move AmbiguousDiffMinusCounter to hunk_header (#1825)

2 files changed, 61 insertions, 63 deletions

diff --git a/src/delta.rs b/src/delta.rs
index 948766f..80c5d7a 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -1,6 +1,5 @@
 use std::borrow::Cow;
 use std::collections::HashMap;
-use std::convert::TryInto;
 use std::io::{self, BufRead, IsTerminal, Write};
 
 use bytelines::ByteLines;
@@ -11,7 +10,7 @@ use crate::config::Config;
 use crate::config::GrepType;
 use crate::features;
 use crate::handlers::grep;
-use crate::handlers::hunk_header::ParsedHunkHeader;
+use crate::handlers::hunk_header::{AmbiguousDiffMinusCounter, ParsedHunkHeader};
 use crate::handlers::{self, merge_conflict};
 use crate::paint::Painter;
 use crate::style::DecorationStyle;
@@ -78,61 +77,6 @@ pub enum Source {
     Unknown,
 }
 
-// The output of `diff -u file1 file2` does not contain a header before the
-// `--- old.lua` / `+++ new.lua` block, and the hunk can of course contain lines
-// starting with '-- '. To avoid interpreting '--- lua comment' as a new header,
-// count the minus lines in a hunk (provided by the '@@ -1,4 +1,3 @@' header).
-// `diff` itself can not generate two diffs in this ambiguous format, so a second header
-// could just be ignored. But concatenated diffs exist and are accepted by `patch`.
-#[derive(Debug)]
-pub struct AmbiguousDiffMinusCounter(isize);
-
-impl AmbiguousDiffMinusCounter {
-    // The internal isize representation avoids calling `if let Some(..)` on every line. For
-    // nearly all input the counter is not needed, in this case it is decremented but ignored.
-    // [min, COUNTER_RELEVANT_IF_GT]   unambiguous diff
-    // (COUNTER_RELEVANT_IF_GT, 0]     handle next '--- ' like a header, and set counter in next @@ block
-    // [1, max]                        counting minus lines in ambiguous header
-    const COUNTER_RELEVANT_IF_GREATER_THAN: isize = -4096; // -1 works too, but be defensive
-    const EXPECT_DIFF_3DASH_HEADER: isize = 0;
-    pub fn not_needed() -> Self {
-        Self(Self::COUNTER_RELEVANT_IF_GREATER_THAN)
-    }
-    pub fn count_from(lines: usize) -> Self {
-        Self(
-            lines
-                .try_into()
-                .unwrap_or(Self::COUNTER_RELEVANT_IF_GREATER_THAN),
-        )
-    }
-    pub fn prepare_to_count() -> Self {
-        Self(Self::EXPECT_DIFF_3DASH_HEADER)
-    }
-    pub fn three_dashes_expected(&self) -> bool {
-        if self.0 > Self::COUNTER_RELEVANT_IF_GREATER_THAN {
-            self.0 <= Self::EXPECT_DIFF_3DASH_HEADER
-        } else {
-            true
-        }
-    }
-    #[allow(clippy::needless_bool)]
-    pub fn must_count(&mut self) -> bool {
-        let relevant = self.0 > Self::COUNTER_RELEVANT_IF_GREATER_THAN;
-        if relevant {
-            true
-        } else {
-            #[cfg(target_pointer_width = "32")]
-            {
-                self.0 = Self::COUNTER_RELEVANT_IF_GREATER_THAN;
-            }
-            false
-        }
-    }
-    pub fn count_line(&mut self) {
-        self.0 -= 1;
-    }
-}
-
 // Possible transitions, with actions on entry:
 //
 //
diff --git a/src/handlers/hunk_header.rs b/src/handlers/hunk_header.rs
index fd53377..0e94077 100644
--- a/src/handlers/hunk_header.rs
+++ b/src/handlers/hunk_header.rs
@@ -18,12 +18,9 @@
 // src/hunk_header.rs:119: fn write_to_output_buffer( │
 // ───────────────────────────────────────────────────┘
 // ```
-
+use std::convert::TryInto;
 use std::fmt::Write as FmtWrite;
 
-use lazy_static::lazy_static;
-use regex::Regex;
-
 use super::draw;
 use crate::config::{
     Config, HunkHeaderIncludeCodeFragment, HunkHeaderIncludeFilePath, HunkHeaderIncludeLineNumber,
@@ -31,6 +28,8 @@ use crate::config::{
 use crate::delta::{self, DiffType, InMergeConflict, MergeParents, State, StateMachine};
 use crate::paint::{self, BgShouldFill, Painter, StyleSectionSpecifier};
 use crate::style::{DecorationStyle, Style};
+use lazy_static::lazy_static;
+use regex::Regex;
 
 #[derive(Clone, Default, Debug, PartialEq, Eq)]
 pub struct ParsedHunkHeader {
@@ -43,6 +42,62 @@ pub enum HunkHeaderIncludeHunkLabel {
     No,
 }
 
+// The output of `diff -u file1 file2` does not contain a header before the
+// `--- old.lua` / `+++ new.lua` block, and the hunk can of course contain lines
+// starting with '-- '. To avoid interpreting '--- lua comment' as a new header,
+// count the minus lines in a hunk (provided by the '@@ -1,4 +1,3 @@' header).
+// `diff` itself can not generate two diffs in this ambiguous format, so a second header
+// could just be ignored. But concatenated diffs exist and are accepted by `patch`.
+#[derive(Debug)]
+pub struct AmbiguousDiffMinusCounter(isize);
+
+impl AmbiguousDiffMinusCounter {
+    // The internal isize representation avoids calling `if let Some(..)` on every line. For
+    // nearly all input the counter is not needed, in this case it is decremented but ignored.
+    // [min, COUNTER_RELEVANT_IF_GT]   unambiguous diff
+    // (COUNTER_RELEVANT_IF_GT, 0]     handle next '--- ' like a header, and set counter in next @@ block
+    // [1, max]                        counting minus lines in ambiguous header
+    const COUNTER_RELEVANT_IF_GREATER_THAN: isize = -4096; // -1 works too, but be defensive
+    const EXPECT_DIFF_3DASH_HEADER: isize = 0;
+
+    pub fn not_needed() -> Self {
+        Self(Self::COUNTER_RELEVANT_IF_GREATER_THAN)
+    }
+    pub fn prepare_to_count() -> Self {
+        Self(Self::EXPECT_DIFF_3DASH_HEADER)
+    }
+    pub fn three_dashes_expected(&self) -> bool {
+        if self.0 > Self::COUNTER_RELEVANT_IF_GREATER_THAN {
+            self.0 <= Self::EXPECT_DIFF_3DASH_HEADER
+        } else {
+            true
+        }
+    }
+    pub fn count_line(&mut self) {
+        self.0 -= 1;
+    }
+    fn count_from(lines: usize) -> Self {
+        Self(
+            lines
+                .try_into()
+                .unwrap_or(Self::COUNTER_RELEVANT_IF_GREATER_THAN),
+        )
+    }
+    #[allow(clippy::needless_bool)]
+    fn must_count(&mut self) -> bool {
+        let relevant = self.0 > Self::COUNTER_RELEVANT_IF_GREATER_THAN;
+        if relevant {
+            true
+        } else {
+            #[cfg(target_pointer_width = "32")]
+            {
+                self.0 = Self::COUNTER_RELEVANT_IF_GREATER_THAN;
+            }
+            false
+        }
+    }
+}
+
 impl<'a> StateMachine<'a> {
     #[inline]
     fn test_hunk_header_line(&self) -> bool {
@@ -77,8 +132,7 @@ impl<'a> StateMachine<'a> {
                 if let &[(_, minus_lines), (_, _plus_lines), ..] =
                     parsed_hunk_header.line_numbers_and_hunk_lengths.as_slice()
                 {
-                    self.minus_line_counter =
-                        delta::AmbiguousDiffMinusCounter::count_from(minus_lines);
+                    self.minus_line_counter = AmbiguousDiffMinusCounter::count_from(minus_lines);
                 }
             }