ripgrep: add --pcre2-version flag

This flag will output details about the version of PCRE2 that ripgrep
is using (if any).

5 files changed, 58 insertions, 5 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9b7f609d..aab281f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,8 @@ Feature enhancements:
   ripgrep's exit status logic should now match GNU grep. See updated man page.
 * [FEATURE #1170](https://github.com/BurntSushi/ripgrep/pull/1170):
   Add `--ignore-file-case-insensitive` for case insensitive .ignore globs.
+* FEATURE:
+  Add `--pcre2-version` for querying showing PCRE2 version information.
 
 Bug fixes:
 
diff --git a/complete/_rg b/complete/_rg
index f20a5a07..f26a688d 100644
--- a/complete/_rg
+++ b/complete/_rg
@@ -43,6 +43,7 @@ _rg() {
     + '(exclusive)' # Misc. fully exclusive options
     '(: * -)'{-h,--help}'[display help information]'
     '(: * -)'{-V,--version}'[display version information]'
+    '(: * -)'--pcre2-version'[print the version of PCRE2 used by ripgrep, if available]'
 
     + '(buffered)' # buffering options
     '--line-buffered[force line buffering]'
diff --git a/src/app.rs b/src/app.rs
index c410b5fd..b102d7cd 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -605,6 +605,7 @@ pub fn all_args_and_flags() -> Vec<RGArg> {
     flag_path_separator(&mut args);
     flag_passthru(&mut args);
     flag_pcre2(&mut args);
+    flag_pcre2_version(&mut args);
     flag_pre(&mut args);
     flag_pre_glob(&mut args);
     flag_pretty(&mut args);
@@ -651,7 +652,7 @@ will be provided. Namely, the following is equivalent to the above:
     let arg = RGArg::positional("pattern", "PATTERN")
         .help(SHORT).long_help(LONG)
         .required_unless(&[
-            "file", "files", "regexp", "type-list",
+            "file", "files", "regexp", "type-list", "pcre2-version",
         ]);
     args.push(arg);
 }
@@ -1946,6 +1947,18 @@ This flag can be disabled with --no-pcre2.
     args.push(arg);
 }
 
+fn flag_pcre2_version(args: &mut Vec<RGArg>) {
+    const SHORT: &str = "Print the version of PCRE2 that ripgrep uses.";
+    const LONG: &str = long!("\
+When this flag is present, ripgrep will print the version of PCRE2 in use,
+along with other information, and then exit. If PCRE2 is not available, then
+ripgrep will print an error message and exit with an error code.
+");
+    let arg = RGArg::switch("pcre2-version")
+        .help(SHORT).long_help(LONG);
+    args.push(arg);
+}
+
 fn flag_pre(args: &mut Vec<RGArg>) {
     const SHORT: &str = "search outputs of COMMAND FILE for each FILE";
     const LONG: &str = long!("\
diff --git a/src/args.rs b/src/args.rs
index 1a5b8a31..414bf815 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -73,6 +73,8 @@ pub enum Command {
     /// List all file type definitions configured, including the default file
     /// types and any additional file types added to the command line.
     Types,
+    /// Print the version of PCRE2 in use.
+    PCRE2Version,
 }
 
 impl Command {
@@ -82,7 +84,11 @@ impl Command {
 
         match *self {
             Search | SearchParallel => true,
-            SearchNever | Files | FilesParallel | Types => false,
+            | SearchNever
+            | Files
+            | FilesParallel
+            | Types
+            | PCRE2Version => false,
         }
     }
 }
@@ -235,7 +241,9 @@ impl Args {
         let threads = self.matches().threads()?;
         let one_thread = is_one_search || threads == 1;
 
-        Ok(if self.matches().is_present("type-list") {
+        Ok(if self.matches().is_present("pcre2-version") {
+            Command::PCRE2Version
+        } else if self.matches().is_present("type-list") {
             Command::Types
         } else if self.matches().is_present("files") {
             if one_thread {
@@ -685,8 +693,8 @@ impl ArgMatches {
             .word(self.is_present("word-regexp"));
         // For whatever reason, the JIT craps out during regex compilation with
         // a "no more memory" error on 32 bit systems. So don't use it there.
-        if !cfg!(target_pointer_width = "32") {
             builder.jit_if_available(true);
+        if cfg!(target_pointer_width = "64") {
         }
         if self.pcre2_unicode() {
             builder.utf(true).ucp(true);
@@ -1278,7 +1286,8 @@ impl ArgMatches {
             !cli::is_readable_stdin()
             || (self.is_present("file") && file_is_stdin)
             || self.is_present("files")
-            || self.is_present("type-list");
+            || self.is_present("type-list")
+            || self.is_present("pcre2-version");
         if search_cwd {
             Path::new("./").to_path_buf()
         } else {
diff --git a/src/main.rs b/src/main.rs
index 63dab998..f607422d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -39,6 +39,7 @@ fn try_main(args: Args) -> Result<()> {
             Files => files(&args),
             FilesParallel => files_parallel(&args),
             Types => types(&args),
+            PCRE2Version => pcre2_version(&args),
         }?;
     if matched && (args.quiet() || !messages::errored()) {
         process::exit(0)
@@ -275,3 +276,30 @@ fn types(args: &Args) -> Result<bool> {
     }
     Ok(count > 0)
 }
+
+/// The top-level entry point for --pcre2-version.
+fn pcre2_version(args: &Args) -> Result<bool> {
+    #[cfg(feature = "pcre2")]
+    fn imp(args: &Args) -> Result<bool> {
+        use grep::pcre2;
+
+        let mut stdout = args.stdout();
+
+        let (major, minor) = pcre2::version();
+        writeln!(stdout, "PCRE2 {}.{} is available", major, minor)?;
+
+        if cfg!(target_pointer_width = "64") && pcre2::is_jit_available() {
+            writeln!(stdout, "JIT is available")?;
+        }
+        Ok(true)
+    }
+
+    #[cfg(not(feature = "pcre2"))]
+    fn imp(args: &Args) -> Result<bool> {
+        let mut stdout = args.stdout();
+        writeln!(stdout, "PCRE2 is not available in this build of ripgrep.")?;
+        Ok(false)
+    }
+
+    imp(args)
+}