Support wasm-wasip1 target

.cargo/config.toml

@@ -0,0 +1,6 @@
+[target.wasm32-wasip1]
+rustflags = [
+  "-L/opt/wasi-sdk/share/wasi-sysroot/lib/wasm32-wasi",
+  "-Clink-arg=-lc++",
+  "-Clink-arg=-lc++abi"
+]

.github/workflows/release.yml

@@ -37,6 +37,8 @@ jobs:
           # detects that they need cross).
           - target: x86_64-unknown-linux-musl
             os: ubuntu-22.04
+          - target: wasm32-wasip1
+            os: ubuntu-24.04
           - target: aarch64-unknown-linux-gnu
             os: ubuntu-22.04
           - target: aarch64-pc-windows-msvc
@@ -46,6 +48,13 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       # v4.2.2
+      - run: |
+          wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-29/wasi-sdk-29.0-x86_64-linux.deb
+          sudo apt-get install ./wasi-sdk-29.0-x86_64-linux.deb
+          rm ./wasi-sdk-29.0-x86_64-linux.deb
+          rustup override set stable
+          rustup target add wasm32-wasip1
+        if: ${{ matrix.target == 'wasm32-wasip1' }}
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: taiki-e/upload-rust-binary-action@v1
         with:
@@ -59,6 +68,11 @@ jobs:
         env:
           # (required)
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          WASI_SDK_PATH: /opt/wasi-sdk
+          WASI_SYSROOT: /opt/wasi-sdk/share/wasi-sysroot
+          CC_wasm32_wasip1: /opt/wasi-sdk/bin/clang
+          AR_wasm32_wasip1: /opt/wasi-sdk/bin/llvm-ar
+          CFLAGS_wasm32_wasip1: "--sysroot=/opt/wasi-sdk/share/wasi-sysroot"
 
   push_crates_io:
     runs-on: ubuntu-22.04

Cargo.toml

@@ -59,7 +59,6 @@ tree_magic_mini = "3.1.6"
 
 bumpalo = "3.16.0"
 unicode-width = "0.1.9"
-crossterm = { version = "0.28.0", features = ["windows"] }
 glob = "0.3.1"
 strum = { version = "0.26", features = ["derive"] }
 hashbrown = "0.14.0"
@@ -128,7 +127,10 @@ tree-sitter-xml = "0.7.0"
 tree-sitter-yaml = "0.7.0"
 tree-sitter-zig = "1.1.2"
 
-[target.'cfg(not(any(target_env = "msvc", target_os = "illumos", target_os = "freebsd")))'.dependencies]
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+crossterm = { version = "0.28.0", features = ["windows"] }
+
+[target.'cfg(not(any(target_env = "msvc", target_os = "illumos", target_os = "freebsd", target_arch = "wasm32")))'.dependencies]
 tikv-jemallocator = "0.6"
 
 [dev-dependencies]

src/files.rs

@@ -78,6 +78,7 @@ fn read_file_arg(file_arg: &FileArgument) -> std::io::Result<Vec<u8>> {
 }
 
 /// Write a human-friendly description of `e` to stderr.
+#[cfg(not(target_arch = "wasm32"))]
 fn eprint_read_error(file_arg: &FileArgument, e: &std::io::Error) {
     match e.kind() {
         std::io::ErrorKind::NotFound => {
@@ -95,12 +96,26 @@ fn eprint_read_error(file_arg: &FileArgument, e: &std::io::Error) {
     };
 }
 
+#[cfg(target_arch = "wasm32")]
+fn eprint_read_error(file_arg: &FileArgument, e: &std::io::Error) {
+    // For the browser/WASM demo, fail softly so we can keep running.
+    println!("WASM read error on {} ({:?})", file_arg, e.kind());
+}
+
 pub(crate) fn read_or_die(path: &Path) -> Vec<u8> {
     match fs::read(path) {
         Ok(src) => src,
         Err(e) => {
             eprint_read_error(&FileArgument::NamedPath(path.to_path_buf()), &e);
-            std::process::exit(EXIT_BAD_ARGUMENTS);
+            #[cfg(target_arch = "wasm32")]
+            {
+                // Return empty content in WASM to avoid aborting the demo.
+                return Vec::new();
+            }
+            #[cfg(not(target_arch = "wasm32"))]
+            {
+                std::process::exit(EXIT_BAD_ARGUMENTS);
+            }
         }
     }
 }

src/main.rs

@@ -98,10 +98,20 @@ use crate::parse::syntax;
 ///
 /// For reference, Jemalloc uses 10-20% more time (although up to 33%
 /// more instructions) when testing on sample files.
-#[cfg(not(any(target_env = "msvc", target_os = "illumos", target_os = "freebsd")))]
+#[cfg(not(any(
+    target_env = "msvc",
+    target_os = "illumos",
+    target_os = "freebsd",
+    target_arch = "wasm32"
+)))]
 use tikv_jemallocator::Jemalloc;
 
-#[cfg(not(any(target_env = "msvc", target_os = "illumos", target_os = "freebsd")))]
+#[cfg(not(any(
+    target_env = "msvc",
+    target_os = "illumos",
+    target_os = "freebsd",
+    target_arch = "wasm32"
+)))]
 #[global_allocator]
 static GLOBAL: Jemalloc = Jemalloc;
 

src/options.rs

@@ -8,7 +8,6 @@ use std::{
 };
 
 use clap::{crate_authors, crate_description, value_parser, Arg, ArgAction, Command};
-use crossterm::tty::IsTty;
 use owo_colors::OwoColorize as _;
 
 use crate::{
@@ -51,6 +50,30 @@ pub(crate) struct DisplayOptions {
 
 pub(crate) const DEFAULT_TERMINAL_WIDTH: usize = 80;
 
+#[cfg(not(target_arch = "wasm32"))]
+fn stdout_is_tty() -> bool {
+    use crossterm::tty::IsTty;
+    std::io::stdout().is_tty()
+}
+
+#[cfg(target_arch = "wasm32")]
+fn stdout_is_tty() -> bool {
+    false
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+fn terminal_columns() -> Option<usize> {
+    crossterm::terminal::size()
+        .ok()
+        .map(|(cols, _rows)| cols as usize)
+        .filter(|cols| *cols > 0)
+}
+
+#[cfg(target_arch = "wasm32")]
+fn terminal_columns() -> Option<usize> {
+    None
+}
+
 impl Default for DisplayOptions {
     fn default() -> Self {
         Self {
@@ -125,7 +148,7 @@ fn app() -> clap::Command {
     ));
 
     after_help.push_str("\n\nSee the full manual at ");
-    if std::io::stdout().is_tty() {
+    if stdout_is_tty() {
         // Make the link to the manual clickable in terminals that
         // support OSC 8, the ANSI escape code for hyperlinks.
         //
@@ -596,6 +619,7 @@ fn common_path_suffix(lhs_path: &Path, rhs_path: &Path) -> Option<String> {
 }
 
 /// Does `path` look like "/tmp/git-blob-abcdef/modified_field.txt"?
+#[cfg(not(target_arch = "wasm32"))]
 fn is_git_tmpfile(path: &Path) -> bool {
     let Ok(rel_path) = path.strip_prefix(std::env::temp_dir()) else {
         return false;
@@ -612,6 +636,12 @@ fn is_git_tmpfile(path: &Path) -> bool {
         .starts_with("git-blob-")
 }
 
+#[cfg(target_arch = "wasm32")]
+fn is_git_tmpfile(_path: &Path) -> bool {
+    // WASI environments may not have a writable /tmp; skip special-casing.
+    false
+}
+
 fn build_display_path(lhs_path: &FileArgument, rhs_path: &FileArgument) -> String {
     match (lhs_path, rhs_path) {
         (FileArgument::NamedPath(lhs), FileArgument::NamedPath(rhs)) => {
@@ -1002,10 +1032,8 @@ pub(crate) fn parse_args() -> Mode {
 /// Try to work out the width of the terminal we're on, or fall back
 /// to a sensible default value.
 fn detect_terminal_width() -> usize {
-    if let Ok((columns, _rows)) = crossterm::terminal::size() {
-        if columns > 0 {
-            return columns.into();
-        }
+    if let Some(columns) = terminal_columns() {
+        return columns;
     }
 
     // If crossterm couldn't detect the terminal width, use the
@@ -1036,7 +1064,7 @@ pub(crate) fn should_use_color(color_output: ColorOutput) -> bool {
 fn detect_color_support() -> bool {
     // TODO: consider following the env parsing logic in git_config_bool
     // in config.c.
-    std::io::stdout().is_tty() || env::var("GIT_PAGER_IN_USE").is_ok()
+    stdout_is_tty() || env::var("GIT_PAGER_IN_USE").is_ok()
 }
 
 #[cfg(test)]