mod: read file from argument for diff contents

For example you can run the following bash command:

```bash
tui-diff <(git diff)
```

With this command you create a temporary file containing
contents of the `git diff` command and is provided to
`tui-diff` to open and render.

.gitea/workflows/release.yaml

@@ -15,7 +15,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Setup zig installation
-        uses: mlugg/setup-zig@v2
+        uses: https://codeberg.org/mlugg/setup-zig@v2
         with:
           version: master
       - name: Lint check

.gitea/workflows/test.yaml

@@ -14,7 +14,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Setup zig installation
-        uses: mlugg/setup-zig@v2
+        uses: https://codeberg.org/mlugg/setup-zig@v2
         with:
           version: master
       - name: Lint check

src/elements.zig

@@ -83,7 +83,6 @@ pub fn Tree(App: type) type {
             return .{ .x = width };
         }
 
-
         fn handle(ctx: *anyopaque, model: *App.Model, event: App.Event) !void {
             const this: *@This() = @ptrCast(@alignCast(ctx));
             switch (event) {

src/main.zig

@@ -3,106 +3,106 @@
 // FIX known issues:
 
 const diff =
-\\diff --git a/build.zig.zon b/build.zig.zon
-\\index a039487..944fc49 100644
-\\--- a/build.zig.zon
-\\+++ b/build.zig.zon
-\\@@ -3,8 +3,8 @@
-\\     .version = "0.0.1",
-\\     .dependencies = .{
-\\         .zterm = .{
-\\-            .url = "git+https://gitea.yves-biener.de/yves-biener/zterm#e972a2ea0f7a9f8caffd439ef206474b46475f91",
-\\-            .hash = "zterm-0.3.0-1xmmENkhHAB2rmNJFH-9rRqiRLnT673xwuMrqLwOnlT_",
-\\+            .url = "git+https://gitea.yves-biener.de/yves-biener/zterm#b1a0d60ae379bb91b862d7c4a8a2210cd74c4387",
-\\+            .hash = "zterm-0.3.0-1xmmEMotHACXUXNtsX1P2iz3XQgabNz1PfF7oazYtNam",
-\\         },
-\\     },
-\\     .minimum_zig_version = "0.16.0-dev.1254+bf15c791f",
-\\diff --git a/src/elements.zig b/src/elements.zig
-\\index c0225ae..fb1ad68 100644
-\\--- a/src/elements.zig
-\\+++ b/src/elements.zig
-\\@@ -59,6 +59,7 @@ pub fn Tree(App: type) type {
-\\                 .ptr = this,
-\\                 .vtable = &.{
-\\                     .resize = resize,
-\\+                    .minSize = minSize,
-\\                     .handle = handle,
-\\                     .content = content,
-\\                 },
-\\@@ -70,6 +71,19 @@ pub fn Tree(App: type) type {
-\\             this.size = size;
-\\         }
-\\
-\\+        fn minSize(ctx: *anyopaque, model: *const App.Model, _: Point) Point {
-\\+            // NOTE as we assume the model contents do not change we could calculate the
-\\+            // maximum width required for this `Element` and return that, instead of
-\\+            // calculating the width every time anew. For now this works fine.
-\\+            const this: *@This() = @ptrCast(@alignCast(ctx));
-\\+            const changes: []const Model.Index = model.changes.keys();
-\\+            const files = changes[this.scrollback..];
-\\+            var width: u16 = 0;
-\\+            for (files) |file| width = @max(@as(u16, @intCast(file.len)), width);
-\\+            return .{ .x = width };
-\\+        }
-\\+
-\\+
-\\         fn handle(ctx: *anyopaque, model: *App.Model, event: App.Event) !void {
-\\             const this: *@This() = @ptrCast(@alignCast(ctx));
-\\             switch (event) {
-\\@@ -78,7 +92,17 @@ pub fn Tree(App: type) type {
-\\                     this.scrollback = 0;
-\\                     this.idx = 0;
-\\                 },
-\\-                // TODO also support key inputs to change the current file?
-\\+                .key => |key| {
-\\+                   if (key.eql(.{ .cp = 'J' }) and this.idx < this.len - 1) {
-\\+                       this.idx += 1;
-\\+                       this.queue.push(.{ .file = this.idx });
-\\+                   }
-\\+
-\\+                   if (key.eql(.{ .cp = 'K' }) and this.idx > 0) {
-\\+                       this.idx -= 1;
-\\+                       this.queue.push(.{ .file = this.idx });
-\\+                   }
-\\+                },
-\\                 .mouse => |mouse| if (this.len > 0) switch (mouse.button) {
-\\                     .left => if (mouse.y + this.scrollback < this.len) {
-\\                         this.idx = mouse.y + this.scrollback;
-\\@@ -112,7 +136,6 @@ pub fn Tree(App: type) type {
-\\                 const row_color: zterm.Color = if (this.idx == idx) .blue else .default;
-\\                 cell_idx = row * size.x;
-\\                 for (0..size.x) |_| {
-\\-                    cell_idx += 1;
-\\                     if (value_idx >= value.len) break;
-\\                     const cp = value[value_idx];
-\\                     defer value_idx += 1;
-\\@@ -128,6 +151,7 @@ pub fn Tree(App: type) type {
-\\                         else => cp,
-\\                     };
-\\                     cells[cell_idx].style.fg = row_color;
-\\+                    cell_idx += 1;
-\\                 }
-\\             }
-\\         }
-\\diff --git a/src/root.zig b/src/root.zig
-\\index 29aa832..54d3631 100644
-\\--- a/src/root.zig
-\\+++ b/src/root.zig
-\\@@ -17,7 +17,11 @@ pub fn Container(App: type, gpa: Allocator, element: *elements.Root(App), tree:
-\\             },
-\\         },
-\\     }, element.element());
-\\-    try root.append(try .init(gpa, .{}, tree.element()));
-\\+    try root.append(try .init(gpa, .{
-\\+        .size = .{
-\\+            .grow = .vertical,
-\\+        },
-\\+    }, tree.element()));
-\\     try root.append(try .init(gpa, .{}, .{})); // empty container holding the scrollable element for the diff of each file
-\\     return root;
-\\ }
-\\
+    \\diff --git a/build.zig.zon b/build.zig.zon
+    \\index a039487..944fc49 100644
+    \\--- a/build.zig.zon
+    \\+++ b/build.zig.zon
+    \\@@ -3,8 +3,8 @@
+    \\     .version = "0.0.1",
+    \\     .dependencies = .{
+    \\         .zterm = .{
+    \\-            .url = "git+https://gitea.yves-biener.de/yves-biener/zterm#e972a2ea0f7a9f8caffd439ef206474b46475f91",
+    \\-            .hash = "zterm-0.3.0-1xmmENkhHAB2rmNJFH-9rRqiRLnT673xwuMrqLwOnlT_",
+    \\+            .url = "git+https://gitea.yves-biener.de/yves-biener/zterm#b1a0d60ae379bb91b862d7c4a8a2210cd74c4387",
+    \\+            .hash = "zterm-0.3.0-1xmmEMotHACXUXNtsX1P2iz3XQgabNz1PfF7oazYtNam",
+    \\         },
+    \\     },
+    \\     .minimum_zig_version = "0.16.0-dev.1254+bf15c791f",
+    \\diff --git a/src/elements.zig b/src/elements.zig
+    \\index c0225ae..fb1ad68 100644
+    \\--- a/src/elements.zig
+    \\+++ b/src/elements.zig
+    \\@@ -59,6 +59,7 @@ pub fn Tree(App: type) type {
+    \\                 .ptr = this,
+    \\                 .vtable = &.{
+    \\                     .resize = resize,
+    \\+                    .minSize = minSize,
+    \\                     .handle = handle,
+    \\                     .content = content,
+    \\                 },
+    \\@@ -70,6 +71,19 @@ pub fn Tree(App: type) type {
+    \\             this.size = size;
+    \\         }
+    \\
+    \\+        fn minSize(ctx: *anyopaque, model: *const App.Model, _: Point) Point {
+    \\+            // NOTE as we assume the model contents do not change we could calculate the
+    \\+            // maximum width required for this `Element` and return that, instead of
+    \\+            // calculating the width every time anew. For now this works fine.
+    \\+            const this: *@This() = @ptrCast(@alignCast(ctx));
+    \\+            const changes: []const Model.Index = model.changes.keys();
+    \\+            const files = changes[this.scrollback..];
+    \\+            var width: u16 = 0;
+    \\+            for (files) |file| width = @max(@as(u16, @intCast(file.len)), width);
+    \\+            return .{ .x = width };
+    \\+        }
+    \\+
+    \\+
+    \\         fn handle(ctx: *anyopaque, model: *App.Model, event: App.Event) !void {
+    \\             const this: *@This() = @ptrCast(@alignCast(ctx));
+    \\             switch (event) {
+    \\@@ -78,7 +92,17 @@ pub fn Tree(App: type) type {
+    \\                     this.scrollback = 0;
+    \\                     this.idx = 0;
+    \\                 },
+    \\-                // TODO also support key inputs to change the current file?
+    \\+                .key => |key| {
+    \\+                   if (key.eql(.{ .cp = 'J' }) and this.idx < this.len - 1) {
+    \\+                       this.idx += 1;
+    \\+                       this.queue.push(.{ .file = this.idx });
+    \\+                   }
+    \\+
+    \\+                   if (key.eql(.{ .cp = 'K' }) and this.idx > 0) {
+    \\+                       this.idx -= 1;
+    \\+                       this.queue.push(.{ .file = this.idx });
+    \\+                   }
+    \\+                },
+    \\                 .mouse => |mouse| if (this.len > 0) switch (mouse.button) {
+    \\                     .left => if (mouse.y + this.scrollback < this.len) {
+    \\                         this.idx = mouse.y + this.scrollback;
+    \\@@ -112,7 +136,6 @@ pub fn Tree(App: type) type {
+    \\                 const row_color: zterm.Color = if (this.idx == idx) .blue else .default;
+    \\                 cell_idx = row * size.x;
+    \\                 for (0..size.x) |_| {
+    \\-                    cell_idx += 1;
+    \\                     if (value_idx >= value.len) break;
+    \\                     const cp = value[value_idx];
+    \\                     defer value_idx += 1;
+    \\@@ -128,6 +151,7 @@ pub fn Tree(App: type) type {
+    \\                         else => cp,
+    \\                     };
+    \\                     cells[cell_idx].style.fg = row_color;
+    \\+                    cell_idx += 1;
+    \\                 }
+    \\             }
+    \\         }
+    \\diff --git a/src/root.zig b/src/root.zig
+    \\index 29aa832..54d3631 100644
+    \\--- a/src/root.zig
+    \\+++ b/src/root.zig
+    \\@@ -17,7 +17,11 @@ pub fn Container(App: type, gpa: Allocator, element: *elements.Root(App), tree:
+    \\             },
+    \\         },
+    \\     }, element.element());
+    \\-    try root.append(try .init(gpa, .{}, tree.element()));
+    \\+    try root.append(try .init(gpa, .{
+    \\+        .size = .{
+    \\+            .grow = .vertical,
+    \\+        },
+    \\+    }, tree.element()));
+    \\     try root.append(try .init(gpa, .{}, .{})); // empty container holding the scrollable element for the diff of each file
+    \\     return root;
+    \\ }
+    \\
 ;
 
 pub fn main() !void {
@@ -120,6 +120,13 @@ pub fn main() !void {
         else => area.allocator(),
     };
 
+    var threaded_io: std.Io.Threaded = .init(allocator, .{});
+    errdefer threaded_io.deinit();
+    const io = threaded_io.io();
+
+    var diff_input: [:0]u8 = undefined;
+    defer allocator.free(diff_input);
+
     // argument handling
     {
         var arg_it = try std.process.argsWithAllocator(allocator);
@@ -127,21 +134,39 @@ pub fn main() !void {
 
         // TODO may there be other options?
         // usage: tui-diff
-
         // skip own executable name
         _ = arg_it.skip();
+
+        // only handle the first argument otherwise ignore!
+        if (arg_it.next()) |file| {
+            var buffer: [4096]u8 = undefined;
+            var stream = std.Io.File.readerStreaming(
+                try std.Io.Dir.openFileAbsolute(
+                    io,
+                    file,
+                    .{ .mode = .read_only },
+                ),
+                io,
+                &buffer,
+            );
+            const reader = &stream.interface;
+            diff_input = try reader.allocRemainingAlignedSentinel(
+                allocator,
+                .unlimited,
+                .of(u8),
+                0,
+            );
+        } else {
+            // TODO detect VCS in the current working directory (and traversing upwards if none found at point?)
+        }
     }
     // tui creation
     errdefer |err| log.err("Application Error: {any}", .{err});
 
-    var threaded_io: std.Io.Threaded = .init(allocator, .{});
-    errdefer threaded_io.deinit();
-    const io = threaded_io.io();
-
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
-    var app: App = .init(io, try .init(allocator, diff));
+    var app: App = .init(io, try .init(allocator, diff_input));
     defer app.model.deinit(allocator);
 
     var element_root: tui_diff.elements.Root(App) = .init(allocator);