Add patch file support (unified & context diffs)

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mergers"
-version = "0.8.1"
+version = "0.8.2"
 edition = "2024"
 description = "A visual diff and merge tool for files and directories"
 license = "GPL-2.0"
@@ -12,13 +12,14 @@ gtk4 = { version = "0.11", features = ["v4_14"] }
 gio = { version = "0.22", features = ["v2_66"] }
 chrono = "0.4"
 notify = "8.2"
-clap = { version = "4.5", features = ["derive"] }
+clap = { version = "4.6", features = ["derive"] }
 sourceview5 = { version = "0.11", features = ["gtk_v4_14"] }
 serde = { version = "1.0", features = ["derive"] }
 toml = "1.0"
+ctrlc = { version = "3.5.2", features = ["termination"] }
 
 [dev-dependencies]
-criterion = { version = "0.5", features = ["html_reports"] }
+criterion = { version = "0.8", features = ["html_reports"] }
 proptest = "1.10"
 tempfile = "3.26"
 

README.md

@@ -21,6 +21,7 @@ A visual diff and merge tool written in Rust with GTK4, inspired by [Meld](https
 - **Chunk navigation** with keyboard shortcuts (with optional wrap-around)
 - **Synchronized scrolling** — chunk-aware vertical sync keeps corresponding lines aligned
 - **Chunk map** — visual overview strips alongside each pane with viewport indicator
+- **Patch viewing** — open `.patch`/`.diff` files to interactively review and apply changes, with conflict markers for failed hunks
 - **Patch export** (unified diff format)
 - **Refresh** (Ctrl+R / F5) — reload files from disk with unsaved-changes confirmation
 - **Open externally** (Ctrl+Shift+O) — open focused file in system default app
@@ -95,6 +96,12 @@ mergers dir1/ dir2/
 # Three-way merge (left, merged, right)
 mergers local.txt merged.txt remote.txt
 
+# Apply a patch to a file (auto-detected from .patch/.diff extension)
+mergers original.txt changes.patch
+
+# Apply a patch to a directory
+mergers project/ changes.patch
+
 # View uncommitted git changes
 mergers .
 
@@ -120,32 +127,35 @@ git mergetool
 
 ## Comparison with Similar Tools
 
-| Feature                           | mergers               | [Meld](https://meldmerge.org/) | [Diffuse](https://github.com/MightyCreak/diffuse) |
-| --------------------------------- | --------------------- | ------------------------------ | ------------------------------------------------- |
-| **File Comparison**               | 2-way, 3-way          | 2-way, 3-way                   | N-way (arbitrary)                                 |
-| **Directory Comparison**          | Yes                   | Yes                            | No                                                |
-| **VCS Integration**               | Git                   | Git, Hg, Bzr, CVS, SVN         | Git, Hg, Bzr, CVS, SVN, Darcs, Monotone, RCS      |
-| **Syntax Highlighting**           | Yes (GtkSourceView 5) | Yes (GtkSourceView)            | Yes                                               |
-| **Word-level Diffs**              | Yes                   | Yes                            | No                                                |
-| **Inline Editing**                | Yes                   | Yes                            | Yes                                               |
-| **Manual Line Alignment**         | No                    | No                             | Yes                                               |
-| **Undo/Redo**                     | Yes                   | Yes                            | Unlimited undo                                    |
-| **Find & Replace**                | Yes                   | Yes                            | Yes                                               |
-| **Go to Line**                    | Yes                   | No                             | No                                                |
-| **Patch Export**                  | Yes                   | No                             | No                                                |
-| **Ignore Whitespace**             | Yes                   | Yes                            | No                                                |
-| **Ignore Blank Lines**            | Yes                   | Yes                            | No                                                |
-| **Text Wrapping Options**         | Yes                   | Yes                            | No                                                |
-| **File Monitoring / Auto-reload** | Yes                   | Yes                            | No                                                |
-| **Synchronized Scrolling**        | Yes                   | Yes                            | No                                                |
-| **Chunk Map (minimap)**           | Yes                   | Yes                            | No                                                |
-| **Conflict Marker Detection**     | Yes                   | No                             | No                                                |
-| **Folder Filters**                | Yes                   | Yes                            | N/A                                               |
-| **Git Mergetool Support**         | Yes                   | Yes                            | Yes                                               |
-| **Custom Pane Labels**            | Yes                   | Yes                            | Yes                                               |
-| **Toolkit**                       | GTK4                  | GTK3                           | GTK3                                              |
-| **Language**                      | Rust                  | Python                         | Python                                            |
-| **License**                       | GPL-2.0               | GPL-2.0                        | GPL-2.0                                           |
+| Feature                           | mergers               | [Meld](https://meldmerge.org/) | [Diffuse](https://github.com/MightyCreak/diffuse) | [Kompare](https://apps.kde.org/kompare/) |
+| --------------------------------- | --------------------- | ------------------------------ | ------------------------------------------------- | ---------------------------------------- |
+| **File Comparison**               | 2-way, 3-way          | 2-way, 3-way                   | N-way (arbitrary)                                 | 2-way                                    |
+| **Directory Comparison**          | Yes                   | Yes                            | No                                                | Yes                                      |
+| **VCS Integration**               | Git                   | Git, Hg, Bzr, CVS, SVN         | Git, Hg, Bzr, CVS, SVN, Darcs, Monotone, RCS      | No                                       |
+| **Syntax Highlighting**           | Yes (GtkSourceView 5) | Yes (GtkSourceView)            | Yes                                               | No                                       |
+| **Word-level Diffs**              | Yes                   | Yes                            | No                                                | No                                       |
+| **Inline Editing**                | Yes                   | Yes                            | Yes                                               | No                                       |
+| **Manual Line Alignment**         | No                    | No                             | Yes                                               | No                                       |
+| **Undo/Redo**                     | Yes                   | Yes                            | Unlimited undo                                    | No                                       |
+| **Find & Replace**                | Yes                   | Yes                            | Yes                                               | No                                       |
+| **Go to Line**                    | Yes                   | No                             | No                                                | No                                       |
+| **Patch Export**                  | Yes                   | No                             | No                                                | Yes                                      |
+| **Patch Viewing/Applying**        | Yes                   | No                             | No                                                | Yes                                      |
+| **Ignore Whitespace**             | Yes                   | Yes                            | No                                                | No                                       |
+| **Ignore Blank Lines**            | Yes                   | Yes                            | No                                                | No                                       |
+| **Text Wrapping Options**         | Yes                   | Yes                            | No                                                | No                                       |
+| **File Monitoring / Auto-reload** | Yes                   | Yes                            | No                                                | No                                       |
+| **Synchronized Scrolling**        | Yes                   | Yes                            | No                                                | No                                       |
+| **Chunk Map (minimap)**           | Yes                   | Yes                            | No                                                | No                                       |
+| **Conflict Marker Detection**     | Yes                   | No                             | No                                                | No                                       |
+| **Diff Statistics**               | No                    | No                             | No                                                | Yes                                      |
+| **Folder Filters**                | Yes                   | Yes                            | N/A                                               | No                                       |
+| **Git Mergetool Support**         | Yes                   | Yes                            | Yes                                               | No                                       |
+| **Custom Pane Labels**            | Yes                   | Yes                            | Yes                                               | No                                       |
+| **Remote File Support**           | Via GVFS              | Via GVFS                       | No                                                | Via KIO                                  |
+| **Toolkit**                       | GTK4                  | GTK3                           | GTK3                                              | Qt (KDE Frameworks)                      |
+| **Language**                      | Rust                  | Python                         | Python                                            | C++                                      |
+| **License**                       | GPL-2.0               | GPL-2.0                        | GPL-2.0                                           | GPL-2.0                                  |
 
 ## Building
 

TESTING.md

@@ -13,6 +13,8 @@ Items marked ✅ are covered by automated UI integration tests (`tests/ui_integr
 - [x] ✅ Single file path: prints error and exits
 - [x] ✅ Non-existent path: prints error and exits
 - [x] ✅ File + directory mix: prints error
+- [x] ✅ File + patch file: opens patch viewing window
+- [x] ✅ Directory + patch file: opens multi-file patch dir comparison
 - [x] ✅ `-L`/`--label` flags: custom pane labels shown for 2-file and 3-file modes
 - [x] ✅ `--version` / `--help`: correct output
 
@@ -47,6 +49,10 @@ Items marked ✅ are covered by automated UI integration tests (`tests/ui_integr
 - [x] ✅ Go to line (Ctrl+L): entry appears; type number + Enter to jump; Escape to dismiss; focus returns to active pane
 - [x] ✅ Blanks toggle: re-diffs ignoring blank lines
 - [x] ✅ Spaces toggle: re-diffs ignoring whitespace
+- [ ] Apply all (⏪ button): copies all non-conflicting chunks right → left
+- [ ] Apply all: single undo operation (one Ctrl+Z reverts everything)
+- [ ] Apply all: skips chunks containing conflict markers (`<<<<<<< original` / `>>>>>>> patch`)
+- [ ] Apply all on binary files: button is disabled
 - [ ] Export patch (Ctrl+Shift+P): save dialog; generates unified diff
 - [x] ✅ Swap panes: swaps content, labels, save paths, dirty state; title updates
 - [x] ✅ Preferences (Ctrl+,): opens Preferences
@@ -153,7 +159,7 @@ Items marked ✅ are covered by automated UI integration tests (`tests/ui_integr
 - [ ] Directory headers above each pane with full path as tooltip
 - [ ] Copy path button next to each header: copies full absolute path to clipboard
 - [ ] Copy path after swap: copies the swapped (current) path, not the original
-- [ ] Status colors: blue (different), orange (left-only), green (right-only), dim italic (missing side)
+- [ ] Status colors: blue (different), orange (left-only), green (right-only), red (conflict), dim italic (missing side)
 
 ### Navigation
 - [x] ✅ Double-click file row: opens diff in new notebook tab
@@ -171,6 +177,10 @@ Items marked ✅ are covered by automated UI integration tests (`tests/ui_integr
 - [ ] Delete (Delete key): trashes selected file with confirmation
 - [x] ✅ Collapse all: collapses every expanded directory row
 - [x] ✅ Expand all: expands every directory row
+- [ ] Apply all non-conflicting (⏪ button): copies all non-conflicting files right → left
+- [ ] Apply all: confirmation dialog shows file count
+- [ ] Apply all: handles modified, new, and deleted files
+- [ ] Apply all: skips conflicting files
 - [ ] Swap panes: rescans, updates headers and window title
 - [ ] Preferences (Ctrl+,)
 
@@ -325,6 +335,60 @@ Items marked ✅ are covered by automated UI integration tests (`tests/ui_integr
 ### Security
 - [ ] Paths with `..` components refused
 
+## Patch Viewing / Applying
+
+### CLI
+- [x] ✅ `mergers file.c patch.diff`: opens single-file patch view (original vs patched)
+- [x] ✅ `mergers dir/ patch.diff`: opens multi-file patch view (dir comparison)
+- [x] ✅ `.diff` extension auto-detected as patch mode
+- [x] ✅ Ctrl+W closes patch window cleanly
+- [ ] `-L` labels applied to patch views
+- [ ] Invalid patch file: error dialog shown
+- [ ] Base path does not exist: error dialog shown
+
+### Single-File Patch
+- [x] ✅ Window title contains "patch" and base filename
+- [x] ✅ Two text panes shown
+- [x] ✅ Left pane: original file content; Right pane: patched result
+- [x] ✅ Right pane contains inserted lines from patch
+- [x] ✅ Chunk label shows change count
+- [x] ✅ Tab label contains "patch"
+- [ ] Conflict hunks shown with `<<<<<<< original` / `>>>>>>> patch` markers in right pane
+- [ ] Labels show base filename and "filename (patched)" (not temp paths)
+- [ ] Window destroy cleans up temp directory
+
+### Multi-File Patch (Dir View)
+- [x] ✅ Window opens successfully
+- [x] ✅ Shows patched files (e.g. "different.txt")
+- [x] ✅ Shows subdirectories from the patch
+- [ ] Left header shows base directory name (not temp path)
+- [ ] Left header tooltip shows original base path (not temp path)
+- [ ] Right header shows "dirname (patched)"
+- [ ] Right header tooltip shows temp directory path
+- [ ] Conflicted files colored red in tree view
+- [ ] Same-status files filtered out of tree view
+- [ ] Empty directories filtered out of tree view
+- [ ] Double-click file: opens diff tab with resolved paths
+- [ ] Diff tab left pane header/tooltip: shows original file path (resolved through symlink)
+- [ ] Diff tab right pane: shows temp patched file path
+- [ ] Unsaved changes dialog shows original path (not temp path)
+
+### Apply All (Dir Patch View)
+- [ ] ⏪ button: confirmation dialog shows file count
+- [ ] Modified files (Different): copied right → left through symlink, then removed from view
+- [ ] New files (RightOnly): created in original directory, parent dirs created as needed
+- [ ] Deleted files (LeftOnly): removed from original directory
+- [ ] Conflicted files: skipped (not applied)
+- [ ] View reloads after apply; applied files vanish from tree
+- [ ] File watcher suppressed during bulk copy (no spurious reloads)
+- [ ] Errors during apply: error dialog shown with details
+
+### Temp Directory Cleanup
+- [ ] Normal window close: temp dir removed (connect_shutdown)
+- [ ] SIGINT (Ctrl+C): temp dir removed (ctrlc handler)
+- [ ] SIGTERM (kill): temp dir removed (ctrlc handler)
+- [ ] Multiple patch windows: all temp dirs tracked and cleaned up
+
 ## Preferences
 
 - [ ] Font: chooser dialog; live-apply

benches/benchmarks.rs

@@ -4,7 +4,9 @@
     clippy::format_collect
 )]
 
-use criterion::{Criterion, black_box, criterion_group, criterion_main};
+use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
 use mergers::{
     _bench::{self, Side},
     myers::{self, DiffChunk, DiffTag},

src/lib.rs

@@ -1,6 +1,7 @@
 use std::path::PathBuf;
 
 pub mod myers;
+pub mod patch;
 pub mod settings;
 pub mod ui;
 pub mod vcs;
@@ -39,6 +40,11 @@ pub enum CompareMode {
         right: PathBuf,
         labels: Vec<String>,
     },
+    Patch {
+        base: PathBuf,
+        patch: PathBuf,
+        labels: Vec<String>,
+    },
     Vcs {
         dir: PathBuf,
     },