1 files changed, 192 insertions, 0 deletions
diff --git a/src/flags.rs b/src/flags.rs
new file mode 100644
index 000000000..8e40ba73b
--- /dev/null
+++ b/src/flags.rs
@@ -0,0 +1,192 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+use binding;
+use libc::c_int;
+use std::ffi::CStr;
+use std::ffi::CString;
+use std::mem;
+
+// Creates vector of strings, Vec<String>
+#[cfg(test)]
+macro_rules! svec {
+    ($($x:expr),*) => (vec![$($x.to_string()),*]);
+}
+
+#[derive(Debug, PartialEq)]
+pub struct DenoFlags {
+  pub help: bool,
+  pub log_debug: bool,
+  pub version: bool,
+  pub reload: bool,
+  pub allow_write: bool,
+  pub allow_net: bool,
+}
+
+pub fn print_usage() {
+  println!(
+    "Usage: deno script.js
+
+--allow-write      Allow file system write access.
+--allow-net        Allow network access.
+-v or --version    Print the version.
+-r or --reload     Reload cached remote resources.
+-D or --log-debug  Log debug output.
+--help             Print this message.
+--v8-options       Print V8 command line options.");
+}
+
+// Parses flags for deno. This does not do v8_set_flags() - call that separately.
+pub fn set_flags(args: Vec<String>) -> (DenoFlags, Vec<String>) {
+  let mut flags = DenoFlags {
+    help: false,
+    version: false,
+    reload: false,
+    log_debug: false,
+    allow_write: false,
+    allow_net: false,
+  };
+  let mut rest = Vec::new();
+  for a in &args {
+    match a.as_str() {
+      "-h" | "--help" => flags.help = true,
+      "-D" | "--log-debug" => flags.log_debug = true,
+      "-v" | "--version" => flags.version = true,
+      "-r" | "--reload" => flags.reload = true,
+      "--allow-write" => flags.allow_write = true,
+      "--allow-net" => flags.allow_net = true,
+      _ => rest.push(a.clone()),
+    }
+  }
+
+  return (flags, rest);
+}
+
+#[test]
+fn test_set_flags_1() {
+  let (flags, rest) = set_flags(svec!["deno", "--version"]);
+  assert!(rest == svec!["deno"]);
+  assert!(
+    flags == DenoFlags {
+      help: false,
+      log_debug: false,
+      version: true,
+      reload: false,
+      allow_write: false,
+      allow_net: false,
+    }
+  );
+}
+
+#[test]
+fn test_set_flags_2() {
+  let (flags, rest) = set_flags(svec!["deno", "-r", "-D", "script.ts"]);
+  assert!(rest == svec!["deno", "script.ts"]);
+  assert!(
+    flags == DenoFlags {
+      help: false,
+      log_debug: true,
+      version: false,
+      reload: true,
+      allow_write: false,
+      allow_net: false,
+    }
+  );
+}
+
+#[test]
+fn test_set_flags_3() {
+  let (flags, rest) =
+    set_flags(svec!["deno", "-r", "script.ts", "--allow-write"]);
+  assert!(rest == svec!["deno", "script.ts"]);
+  assert!(
+    flags == DenoFlags {
+      help: false,
+      log_debug: false,
+      version: false,
+      reload: true,
+      allow_write: true,
+      allow_net: false,
+    }
+  );
+}
+
+// Returns args passed to V8, followed by args passed to JS
+// TODO Rename to v8_set_flags_preprocess
+fn parse_core_args(args: Vec<String>) -> (Vec<String>, Vec<String>) {
+  let mut rest = vec![];
+
+  // Filter out args that shouldn't be passed to V8
+  let mut args: Vec<String> = args
+    .into_iter()
+    .filter(|arg| {
+      if arg.as_str() == "--help" {
+        rest.push(arg.clone());
+        return false;
+      }
+
+      true
+    })
+    .collect();
+
+  // Replace args being sent to V8
+  for idx in 0..args.len() {
+    if args[idx] == "--v8-options" {
+      mem::swap(args.get_mut(idx).unwrap(), &mut String::from("--help"));
+    }
+  }
+
+  (args, rest)
+}
+
+#[test]
+fn test_parse_core_args_1() {
+  let js_args =
+    parse_core_args(vec!["deno".to_string(), "--v8-options".to_string()]);
+  assert!(js_args == (vec!["deno".to_string(), "--help".to_string()], vec![]));
+}
+
+#[test]
+fn test_parse_core_args_2() {
+  let js_args = parse_core_args(vec!["deno".to_string(), "--help".to_string()]);
+  assert!(js_args == (vec!["deno".to_string()], vec!["--help".to_string()]));
+}
+
+// Pass the command line arguments to v8.
+// Returns a vector of command line arguments that v8 did not understand.
+pub fn v8_set_flags(args: Vec<String>) -> Vec<String> {
+  // deno_set_flags(int* argc, char** argv) mutates argc and argv to remove
+  // flags that v8 understands.
+  // First parse core args, then converto to a vector of C strings.
+  let (argv, rest) = parse_core_args(args);
+  let mut argv = argv
+    .iter()
+    .map(|arg| CString::new(arg.as_str()).unwrap().into_bytes_with_nul())
+    .collect::<Vec<_>>();
+
+  // Make a new array, that can be modified by V8::SetFlagsFromCommandLine(),
+  // containing mutable raw pointers to the individual command line args.
+  let mut c_argv = argv
+    .iter_mut()
+    .map(|arg| arg.as_mut_ptr() as *mut i8)
+    .collect::<Vec<_>>();
+  // Store the length of the argv array in a local variable. We'll pass a
+  // pointer to this local variable to deno_set_flags(), which then
+  // updates its value.
+  let mut c_argc = c_argv.len() as c_int;
+  // Let v8 parse the arguments it recognizes and remove them from c_argv.
+  unsafe {
+    // TODO(ry) Rename deno_set_flags to deno_set_v8_flags().
+    binding::deno_set_flags(&mut c_argc, c_argv.as_mut_ptr());
+  };
+  // If c_argc was updated we have to change the length of c_argv to match.
+  c_argv.truncate(c_argc as usize);
+  // Copy the modified arguments list into a proper rust vec and return it.
+  c_argv
+    .iter()
+    .map(|ptr| unsafe {
+      let cstr = CStr::from_ptr(*ptr as *const i8);
+      let slice = cstr.to_str().unwrap();
+      slice.to_string()
+    })
+    .chain(rest.into_iter())
+    .collect()
+}