printf: support %q

src/uu/printf/printf.md

@@ -78,6 +78,9 @@ Fields
  second parameter is min-width, integer
  output below that width is padded with leading zeroes
 
+* `%q`: ARGUMENT is printed in a format that can be reused as shell input, escaping non-printable
+ characters with the proposed POSIX $'' syntax.
+
 * `%f` or `%F`: decimal floating point value
 * `%e` or `%E`: scientific notation floating point value
 * `%g` or `%G`: shorter of specially interpreted decimal or SciNote floating point value.
@@ -181,6 +184,11 @@ All string fields have a 'max width' parameter
  still be interpreted and not throw a warning, you will have problems if you use this for a
  literal whose code begins with zero, as it will be viewed as in `\\0NNN` form.)
 
+* `%q`: escaped string - the string in a format that can be reused as input by most shells.
+ Non-printable characters are escaped with the POSIX proposed ‘$''’ syntax,
+ and shell meta-characters are quoted appropriately.
+ This is an equivalent format to ls --quoting=shell-escape output.
+
 #### CHAR SUBSTITUTIONS
 
 The character field does not have a secondary parameter.

src/uucore/src/lib/features/tokenize/sub.rs

@@ -10,6 +10,7 @@
 //! Subs which have numeric field chars make use of the num_format
 //! submodule
 use crate::error::{UError, UResult};
+use crate::quoting_style::{escape_name, QuotingStyle};
 use itertools::{put_back_n, PutBackN};
 use std::error::Error;
 use std::fmt::Display;
@@ -91,7 +92,7 @@
  // for more dry printing, field characters are grouped
  // in initialization of token.
  let field_type = match field_char {
- 's' | 'b' => FieldType::Strf,
+ 's' | 'b' | 'q' => FieldType::Strf,
  'd' | 'i' | 'u' | 'o' | 'x' | 'X' => FieldType::Intf,
  'f' | 'F' => FieldType::Floatf,
  'a' | 'A' => FieldType::CninetyNineHexFloatf,
@@ -189,7 +190,7 @@
 
  let mut legal_fields = [
  // 'a', 'A', //c99 hex float implementation not yet complete
- 'b', 'c', 'd', 'e', 'E', 'f', 'F', 'g', 'G', 'i', 'o', 's', 'u', 'x', 'X',
+ 'b', 'c', 'd', 'e', 'E', 'f', 'F', 'g', 'G', 'i', 'o', 'q', 's', 'u', 'x', 'X',
  ];
  let mut specifiers = ['h', 'j', 'l', 'L', 't', 'z'];
  legal_fields.sort_unstable();
@@ -260,7 +261,6 @@
  }
  x if legal_fields.binary_search(&x).is_ok() => {
  self.field_char = Some(ch);
- self.text_so_far.push(ch);
  break;
  }
  x if specifiers.binary_search(&x).is_ok() => {
@@ -331,7 +331,7 @@
  if (field_char == 's' && self.min_width_tmp == Some(String::from("0")))
  || (field_char == 'c'
  && (self.min_width_tmp == Some(String::from("0")) || self.past_decimal))
- || (field_char == 'b'
+ || ((field_char == 'b' || field_char == 'q')
  && (self.min_width_tmp.is_some()
  || self.past_decimal
  || self.second_field_tmp.is_some()))
@@ -391,6 +391,7 @@
  // if %s just return arg
  // if %b use UnescapedText module's unescape-fn
  // if %c return first char of arg
+ // if %q return arg which non-printable characters are escaped
  FieldType::Strf | FieldType::Charf => {
  match pf_arg {
  Some(arg_string) => {
@@ -404,11 +405,18 @@
  UnescapedText::from_it_core(writer, &mut a_it, true);
  None
  }
- // for 'c': get iter of string vals,
+ 'q' => Some(escape_name(
+ arg_string.as_ref(),
+ &QuotingStyle::Shell {
+ escape: true,
+ always_quote: false,
+ show_control: false,
+ },
+ )),
  // get opt<char> of first val
  // and map it to opt<String>
- /* 'c' | */
- _ => arg_string.chars().next().map(|x| x.to_string()),
+ 'c' => arg_string.chars().next().map(|x| x.to_string()),
+ _ => unreachable!(),
  }
  }
  None => None,

tests/by-util/test_printf.rs

@@ -112,6 +112,15 @@ fn sub_b_string_handle_escapes() {
  .stdout_only("hello \tworld");
 }
 
+#[test]
+fn sub_b_string_validate_field_params() {
+ new_ucmd!()
+ .args(&["hello %7b", "world"])
+ .run()
+ .stdout_is("hello ")
+ .stderr_is("printf: %7b: invalid conversion specification\n");
+}
+
 #[test]
 fn sub_b_string_ignore_subs() {
  new_ucmd!()
@@ -120,6 +129,31 @@ fn sub_b_string_ignore_subs() {
  .stdout_only("hello world %% %i");
 }
 
+#[test]
+fn sub_q_string_non_printable() {
+ new_ucmd!()
+ .args(&["non-printable: %q", "\"$test\""])
+ .succeeds()
+ .stdout_only("non-printable: '\"$test\"'");
+}
+
+#[test]
+fn sub_q_string_validate_field_params() {
+ new_ucmd!()
+ .args(&["hello %7q", "world"])
+ .run()
+ .stdout_is("hello ")
+ .stderr_is("printf: %7q: invalid conversion specification\n");
+}
+
+#[test]
+fn sub_q_string_special_non_printable() {
+ new_ucmd!()
+ .args(&["non-printable: %q", "test~"])
+ .succeeds()
+ .stdout_only("non-printable: test~");
+}
+
 #[test]
 fn sub_char() {
  new_ucmd!()