> NOTE: This function is not performant and should be avoided. It's not used at all in-tree now, so we can remove it completely after any remaining users are given notice.
		
			
				
	
	
		
			746 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			746 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
/* String manipulation functions. */
 | 
						||
{ lib }:
 | 
						||
let
 | 
						||
 | 
						||
inherit (builtins) length;
 | 
						||
 | 
						||
in
 | 
						||
 | 
						||
rec {
 | 
						||
 | 
						||
  inherit (builtins) stringLength substring head tail isString replaceStrings;
 | 
						||
 | 
						||
  /* Concatenate a list of strings.
 | 
						||
 | 
						||
    Type: concatStrings :: [string] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       concatStrings ["foo" "bar"]
 | 
						||
       => "foobar"
 | 
						||
  */
 | 
						||
  concatStrings = builtins.concatStringsSep "";
 | 
						||
 | 
						||
  /* Map a function over a list and concatenate the resulting strings.
 | 
						||
 | 
						||
    Type: concatMapStrings :: (a -> string) -> [a] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       concatMapStrings (x: "a" + x) ["foo" "bar"]
 | 
						||
       => "afooabar"
 | 
						||
  */
 | 
						||
  concatMapStrings = f: list: concatStrings (map f list);
 | 
						||
 | 
						||
  /* Like `concatMapStrings` except that the f functions also gets the
 | 
						||
     position as a parameter.
 | 
						||
 | 
						||
     Type: concatImapStrings :: (int -> a -> string) -> [a] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       concatImapStrings (pos: x: "${toString pos}-${x}") ["foo" "bar"]
 | 
						||
       => "1-foo2-bar"
 | 
						||
  */
 | 
						||
  concatImapStrings = f: list: concatStrings (lib.imap1 f list);
 | 
						||
 | 
						||
  /* Place an element between each element of a list
 | 
						||
 | 
						||
     Type: intersperse :: a -> [a] -> [a]
 | 
						||
 | 
						||
     Example:
 | 
						||
       intersperse "/" ["usr" "local" "bin"]
 | 
						||
       => ["usr" "/" "local" "/" "bin"].
 | 
						||
  */
 | 
						||
  intersperse =
 | 
						||
    # Separator to add between elements
 | 
						||
    separator:
 | 
						||
    # Input list
 | 
						||
    list:
 | 
						||
    if list == [] || length list == 1
 | 
						||
    then list
 | 
						||
    else tail (lib.concatMap (x: [separator x]) list);
 | 
						||
 | 
						||
  /* Concatenate a list of strings with a separator between each element
 | 
						||
 | 
						||
     Type: concatStringsSep :: string -> [string] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
        concatStringsSep "/" ["usr" "local" "bin"]
 | 
						||
        => "usr/local/bin"
 | 
						||
  */
 | 
						||
  concatStringsSep = builtins.concatStringsSep or (separator: list:
 | 
						||
    concatStrings (intersperse separator list));
 | 
						||
 | 
						||
  /* Maps a function over a list of strings and then concatenates the
 | 
						||
     result with the specified separator interspersed between
 | 
						||
     elements.
 | 
						||
 | 
						||
     Type: concatMapStringsSep :: string -> (string -> string) -> [string] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
        concatMapStringsSep "-" (x: toUpper x)  ["foo" "bar" "baz"]
 | 
						||
        => "FOO-BAR-BAZ"
 | 
						||
  */
 | 
						||
  concatMapStringsSep =
 | 
						||
    # Separator to add between elements
 | 
						||
    sep:
 | 
						||
    # Function to map over the list
 | 
						||
    f:
 | 
						||
    # List of input strings
 | 
						||
    list: concatStringsSep sep (map f list);
 | 
						||
 | 
						||
  /* Same as `concatMapStringsSep`, but the mapping function
 | 
						||
     additionally receives the position of its argument.
 | 
						||
 | 
						||
     Type: concatIMapStringsSep :: string -> (int -> string -> string) -> [string] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       concatImapStringsSep "-" (pos: x: toString (x / pos)) [ 6 6 6 ]
 | 
						||
       => "6-3-2"
 | 
						||
  */
 | 
						||
  concatImapStringsSep =
 | 
						||
    # Separator to add between elements
 | 
						||
    sep:
 | 
						||
    # Function that receives elements and their positions
 | 
						||
    f:
 | 
						||
    # List of input strings
 | 
						||
    list: concatStringsSep sep (lib.imap1 f list);
 | 
						||
 | 
						||
  /* Construct a Unix-style, colon-separated search path consisting of
 | 
						||
     the given `subDir` appended to each of the given paths.
 | 
						||
 | 
						||
     Type: makeSearchPath :: string -> [string] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       makeSearchPath "bin" ["/root" "/usr" "/usr/local"]
 | 
						||
       => "/root/bin:/usr/bin:/usr/local/bin"
 | 
						||
       makeSearchPath "bin" [""]
 | 
						||
       => "/bin"
 | 
						||
  */
 | 
						||
  makeSearchPath =
 | 
						||
    # Directory name to append
 | 
						||
    subDir:
 | 
						||
    # List of base paths
 | 
						||
    paths:
 | 
						||
    concatStringsSep ":" (map (path: path + "/" + subDir) (builtins.filter (x: x != null) paths));
 | 
						||
 | 
						||
  /* Construct a Unix-style search path by appending the given
 | 
						||
     `subDir` to the specified `output` of each of the packages. If no
 | 
						||
     output by the given name is found, fallback to `.out` and then to
 | 
						||
     the default.
 | 
						||
 | 
						||
     Type: string -> string -> [package] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       makeSearchPathOutput "dev" "bin" [ pkgs.openssl pkgs.zlib ]
 | 
						||
       => "/nix/store/9rz8gxhzf8sw4kf2j2f1grr49w8zx5vj-openssl-1.0.1r-dev/bin:/nix/store/wwh7mhwh269sfjkm6k5665b5kgp7jrk2-zlib-1.2.8/bin"
 | 
						||
  */
 | 
						||
  makeSearchPathOutput =
 | 
						||
    # Package output to use
 | 
						||
    output:
 | 
						||
    # Directory name to append
 | 
						||
    subDir:
 | 
						||
    # List of packages
 | 
						||
    pkgs: makeSearchPath subDir (map (lib.getOutput output) pkgs);
 | 
						||
 | 
						||
  /* Construct a library search path (such as RPATH) containing the
 | 
						||
     libraries for a set of packages
 | 
						||
 | 
						||
     Example:
 | 
						||
       makeLibraryPath [ "/usr" "/usr/local" ]
 | 
						||
       => "/usr/lib:/usr/local/lib"
 | 
						||
       pkgs = import <nixpkgs> { }
 | 
						||
       makeLibraryPath [ pkgs.openssl pkgs.zlib ]
 | 
						||
       => "/nix/store/9rz8gxhzf8sw4kf2j2f1grr49w8zx5vj-openssl-1.0.1r/lib:/nix/store/wwh7mhwh269sfjkm6k5665b5kgp7jrk2-zlib-1.2.8/lib"
 | 
						||
  */
 | 
						||
  makeLibraryPath = makeSearchPathOutput "lib" "lib";
 | 
						||
 | 
						||
  /* Construct a binary search path (such as $PATH) containing the
 | 
						||
     binaries for a set of packages.
 | 
						||
 | 
						||
     Example:
 | 
						||
       makeBinPath ["/root" "/usr" "/usr/local"]
 | 
						||
       => "/root/bin:/usr/bin:/usr/local/bin"
 | 
						||
  */
 | 
						||
  makeBinPath = makeSearchPathOutput "bin" "bin";
 | 
						||
 | 
						||
  /* Depending on the boolean `cond', return either the given string
 | 
						||
     or the empty string. Useful to concatenate against a bigger string.
 | 
						||
 | 
						||
     Type: optionalString :: bool -> string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       optionalString true "some-string"
 | 
						||
       => "some-string"
 | 
						||
       optionalString false "some-string"
 | 
						||
       => ""
 | 
						||
  */
 | 
						||
  optionalString =
 | 
						||
    # Condition
 | 
						||
    cond:
 | 
						||
    # String to return if condition is true
 | 
						||
    string: if cond then string else "";
 | 
						||
 | 
						||
  /* Determine whether a string has given prefix.
 | 
						||
 | 
						||
     Type: hasPrefix :: string -> string -> bool
 | 
						||
 | 
						||
     Example:
 | 
						||
       hasPrefix "foo" "foobar"
 | 
						||
       => true
 | 
						||
       hasPrefix "foo" "barfoo"
 | 
						||
       => false
 | 
						||
  */
 | 
						||
  hasPrefix =
 | 
						||
    # Prefix to check for
 | 
						||
    pref:
 | 
						||
    # Input string
 | 
						||
    str: substring 0 (stringLength pref) str == pref;
 | 
						||
 | 
						||
  /* Determine whether a string has given suffix.
 | 
						||
 | 
						||
     Type: hasSuffix :: string -> string -> bool
 | 
						||
 | 
						||
     Example:
 | 
						||
       hasSuffix "foo" "foobar"
 | 
						||
       => false
 | 
						||
       hasSuffix "foo" "barfoo"
 | 
						||
       => true
 | 
						||
  */
 | 
						||
  hasSuffix =
 | 
						||
    # Suffix to check for
 | 
						||
    suffix:
 | 
						||
    # Input string
 | 
						||
    content:
 | 
						||
    let
 | 
						||
      lenContent = stringLength content;
 | 
						||
      lenSuffix = stringLength suffix;
 | 
						||
    in lenContent >= lenSuffix &&
 | 
						||
       substring (lenContent - lenSuffix) lenContent content == suffix;
 | 
						||
 | 
						||
  /* Determine whether a string contains the given infix
 | 
						||
 | 
						||
    Type: hasInfix :: string -> string -> bool
 | 
						||
 | 
						||
    Example:
 | 
						||
      hasInfix "bc" "abcd"
 | 
						||
      => true
 | 
						||
      hasInfix "ab" "abcd"
 | 
						||
      => true
 | 
						||
      hasInfix "cd" "abcd"
 | 
						||
      => true
 | 
						||
      hasInfix "foo" "abcd"
 | 
						||
      => false
 | 
						||
  */
 | 
						||
  hasInfix = infix: content:
 | 
						||
    let
 | 
						||
      drop = x: substring 1 (stringLength x) x;
 | 
						||
    in hasPrefix infix content
 | 
						||
      || content != "" && hasInfix infix (drop content);
 | 
						||
 | 
						||
  /* Convert a string to a list of characters (i.e. singleton strings).
 | 
						||
     This allows you to, e.g., map a function over each character.  However,
 | 
						||
     note that this will likely be horribly inefficient; Nix is not a
 | 
						||
     general purpose programming language. Complex string manipulations
 | 
						||
     should, if appropriate, be done in a derivation.
 | 
						||
     Also note that Nix treats strings as a list of bytes and thus doesn't
 | 
						||
     handle unicode.
 | 
						||
 | 
						||
     Type: stringToCharacters :: string -> [string]
 | 
						||
 | 
						||
     Example:
 | 
						||
       stringToCharacters ""
 | 
						||
       => [ ]
 | 
						||
       stringToCharacters "abc"
 | 
						||
       => [ "a" "b" "c" ]
 | 
						||
       stringToCharacters "💩"
 | 
						||
       => [ "<EFBFBD>" "<EFBFBD>" "<EFBFBD>" "<EFBFBD>" ]
 | 
						||
  */
 | 
						||
  stringToCharacters = s:
 | 
						||
    map (p: substring p 1 s) (lib.range 0 (stringLength s - 1));
 | 
						||
 | 
						||
  /* Manipulate a string character by character and replace them by
 | 
						||
     strings before concatenating the results.
 | 
						||
 | 
						||
     Type: stringAsChars :: (string -> string) -> string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       stringAsChars (x: if x == "a" then "i" else x) "nax"
 | 
						||
       => "nix"
 | 
						||
  */
 | 
						||
  stringAsChars =
 | 
						||
    # Function to map over each individual character
 | 
						||
    f:
 | 
						||
    # Input string
 | 
						||
    s: concatStrings (
 | 
						||
      map f (stringToCharacters s)
 | 
						||
    );
 | 
						||
 | 
						||
  /* Escape occurrence of the elements of `list` in `string` by
 | 
						||
     prefixing it with a backslash.
 | 
						||
 | 
						||
     Type: escape :: [string] -> string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       escape ["(" ")"] "(foo)"
 | 
						||
       => "\\(foo\\)"
 | 
						||
  */
 | 
						||
  escape = list: replaceChars list (map (c: "\\${c}") list);
 | 
						||
 | 
						||
  /* Quote string to be used safely within the Bourne shell.
 | 
						||
 | 
						||
     Type: escapeShellArg :: string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       escapeShellArg "esc'ape\nme"
 | 
						||
       => "'esc'\\''ape\nme'"
 | 
						||
  */
 | 
						||
  escapeShellArg = arg: "'${replaceStrings ["'"] ["'\\''"] (toString arg)}'";
 | 
						||
 | 
						||
  /* Quote all arguments to be safely passed to the Bourne shell.
 | 
						||
 | 
						||
     Type: escapeShellArgs :: [string] -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       escapeShellArgs ["one" "two three" "four'five"]
 | 
						||
       => "'one' 'two three' 'four'\\''five'"
 | 
						||
  */
 | 
						||
  escapeShellArgs = concatMapStringsSep " " escapeShellArg;
 | 
						||
 | 
						||
  /* Turn a string into a Nix expression representing that string
 | 
						||
 | 
						||
     Type: string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       escapeNixString "hello\${}\n"
 | 
						||
       => "\"hello\\\${}\\n\""
 | 
						||
  */
 | 
						||
  escapeNixString = s: escape ["$"] (builtins.toJSON s);
 | 
						||
 | 
						||
  /* Quotes a string if it can't be used as an identifier directly.
 | 
						||
 | 
						||
     Type: string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       escapeNixIdentifier "hello"
 | 
						||
       => "hello"
 | 
						||
       escapeNixIdentifier "0abc"
 | 
						||
       => "\"0abc\""
 | 
						||
  */
 | 
						||
  escapeNixIdentifier = s:
 | 
						||
    # Regex from https://github.com/NixOS/nix/blob/d048577909e383439c2549e849c5c2f2016c997e/src/libexpr/lexer.l#L91
 | 
						||
    if builtins.match "[a-zA-Z_][a-zA-Z0-9_'-]*" s != null
 | 
						||
    then s else escapeNixString s;
 | 
						||
 | 
						||
  # Obsolete - use replaceStrings instead.
 | 
						||
  replaceChars = builtins.replaceStrings or (
 | 
						||
    del: new: s:
 | 
						||
    let
 | 
						||
      substList = lib.zipLists del new;
 | 
						||
      subst = c:
 | 
						||
        let found = lib.findFirst (sub: sub.fst == c) null substList; in
 | 
						||
        if found == null then
 | 
						||
          c
 | 
						||
        else
 | 
						||
          found.snd;
 | 
						||
    in
 | 
						||
      stringAsChars subst s);
 | 
						||
 | 
						||
  # Case conversion utilities.
 | 
						||
  lowerChars = stringToCharacters "abcdefghijklmnopqrstuvwxyz";
 | 
						||
  upperChars = stringToCharacters "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 | 
						||
 | 
						||
  /* Converts an ASCII string to lower-case.
 | 
						||
 | 
						||
     Type: toLower :: string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       toLower "HOME"
 | 
						||
       => "home"
 | 
						||
  */
 | 
						||
  toLower = replaceChars upperChars lowerChars;
 | 
						||
 | 
						||
  /* Converts an ASCII string to upper-case.
 | 
						||
 | 
						||
     Type: toUpper :: string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       toUpper "home"
 | 
						||
       => "HOME"
 | 
						||
  */
 | 
						||
  toUpper = replaceChars lowerChars upperChars;
 | 
						||
 | 
						||
  /* Appends string context from another string.  This is an implementation
 | 
						||
     detail of Nix.
 | 
						||
 | 
						||
     Strings in Nix carry an invisible `context` which is a list of strings
 | 
						||
     representing store paths.  If the string is later used in a derivation
 | 
						||
     attribute, the derivation will properly populate the inputDrvs and
 | 
						||
     inputSrcs.
 | 
						||
 | 
						||
     Example:
 | 
						||
       pkgs = import <nixpkgs> { };
 | 
						||
       addContextFrom pkgs.coreutils "bar"
 | 
						||
       => "bar"
 | 
						||
  */
 | 
						||
  addContextFrom = a: b: substring 0 0 a + b;
 | 
						||
 | 
						||
  /* Cut a string with a separator and produces a list of strings which
 | 
						||
     were separated by this separator.
 | 
						||
 | 
						||
     NOTE: this function is not performant and should never be used.
 | 
						||
 | 
						||
     Example:
 | 
						||
       splitString "." "foo.bar.baz"
 | 
						||
       => [ "foo" "bar" "baz" ]
 | 
						||
       splitString "/" "/usr/local/bin"
 | 
						||
       => [ "" "usr" "local" "bin" ]
 | 
						||
  */
 | 
						||
  splitString = _sep: _s:
 | 
						||
    let
 | 
						||
      sep = addContextFrom _s _sep;
 | 
						||
      s = addContextFrom _sep _s;
 | 
						||
      sepLen = stringLength sep;
 | 
						||
      sLen = stringLength s;
 | 
						||
      lastSearch = sLen - sepLen;
 | 
						||
      startWithSep = startAt:
 | 
						||
        substring startAt sepLen s == sep;
 | 
						||
 | 
						||
      recurse = index: startAt:
 | 
						||
        let cutUntil = i: [(substring startAt (i - startAt) s)]; in
 | 
						||
        if index <= lastSearch then
 | 
						||
          if startWithSep index then
 | 
						||
            let restartAt = index + sepLen; in
 | 
						||
            cutUntil index ++ recurse restartAt restartAt
 | 
						||
          else
 | 
						||
            recurse (index + 1) startAt
 | 
						||
        else
 | 
						||
          cutUntil sLen;
 | 
						||
    in
 | 
						||
      recurse 0 0;
 | 
						||
 | 
						||
  /* Return a string without the specified prefix, if the prefix matches.
 | 
						||
 | 
						||
     Type: string -> string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       removePrefix "foo." "foo.bar.baz"
 | 
						||
       => "bar.baz"
 | 
						||
       removePrefix "xxx" "foo.bar.baz"
 | 
						||
       => "foo.bar.baz"
 | 
						||
  */
 | 
						||
  removePrefix =
 | 
						||
    # Prefix to remove if it matches
 | 
						||
    prefix:
 | 
						||
    # Input string
 | 
						||
    str:
 | 
						||
    let
 | 
						||
      preLen = stringLength prefix;
 | 
						||
      sLen = stringLength str;
 | 
						||
    in
 | 
						||
      if hasPrefix prefix str then
 | 
						||
        substring preLen (sLen - preLen) str
 | 
						||
      else
 | 
						||
        str;
 | 
						||
 | 
						||
  /* Return a string without the specified suffix, if the suffix matches.
 | 
						||
 | 
						||
     Type: string -> string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       removeSuffix "front" "homefront"
 | 
						||
       => "home"
 | 
						||
       removeSuffix "xxx" "homefront"
 | 
						||
       => "homefront"
 | 
						||
  */
 | 
						||
  removeSuffix =
 | 
						||
    # Suffix to remove if it matches
 | 
						||
    suffix:
 | 
						||
    # Input string
 | 
						||
    str:
 | 
						||
    let
 | 
						||
      sufLen = stringLength suffix;
 | 
						||
      sLen = stringLength str;
 | 
						||
    in
 | 
						||
      if sufLen <= sLen && suffix == substring (sLen - sufLen) sufLen str then
 | 
						||
        substring 0 (sLen - sufLen) str
 | 
						||
      else
 | 
						||
        str;
 | 
						||
 | 
						||
  /* Return true if string v1 denotes a version older than v2.
 | 
						||
 | 
						||
     Example:
 | 
						||
       versionOlder "1.1" "1.2"
 | 
						||
       => true
 | 
						||
       versionOlder "1.1" "1.1"
 | 
						||
       => false
 | 
						||
  */
 | 
						||
  versionOlder = v1: v2: builtins.compareVersions v2 v1 == 1;
 | 
						||
 | 
						||
  /* Return true if string v1 denotes a version equal to or newer than v2.
 | 
						||
 | 
						||
     Example:
 | 
						||
       versionAtLeast "1.1" "1.0"
 | 
						||
       => true
 | 
						||
       versionAtLeast "1.1" "1.1"
 | 
						||
       => true
 | 
						||
       versionAtLeast "1.1" "1.2"
 | 
						||
       => false
 | 
						||
  */
 | 
						||
  versionAtLeast = v1: v2: !versionOlder v1 v2;
 | 
						||
 | 
						||
  /* This function takes an argument that's either a derivation or a
 | 
						||
     derivation's "name" attribute and extracts the name part from that
 | 
						||
     argument.
 | 
						||
 | 
						||
     Example:
 | 
						||
       getName "youtube-dl-2016.01.01"
 | 
						||
       => "youtube-dl"
 | 
						||
       getName pkgs.youtube-dl
 | 
						||
       => "youtube-dl"
 | 
						||
  */
 | 
						||
  getName = x:
 | 
						||
   let
 | 
						||
     parse = drv: (builtins.parseDrvName drv).name;
 | 
						||
   in if isString x
 | 
						||
      then parse x
 | 
						||
      else x.pname or (parse x.name);
 | 
						||
 | 
						||
  /* This function takes an argument that's either a derivation or a
 | 
						||
     derivation's "name" attribute and extracts the version part from that
 | 
						||
     argument.
 | 
						||
 | 
						||
     Example:
 | 
						||
       getVersion "youtube-dl-2016.01.01"
 | 
						||
       => "2016.01.01"
 | 
						||
       getVersion pkgs.youtube-dl
 | 
						||
       => "2016.01.01"
 | 
						||
  */
 | 
						||
  getVersion = x:
 | 
						||
   let
 | 
						||
     parse = drv: (builtins.parseDrvName drv).version;
 | 
						||
   in if isString x
 | 
						||
      then parse x
 | 
						||
      else x.version or (parse x.name);
 | 
						||
 | 
						||
  /* Extract name with version from URL. Ask for separator which is
 | 
						||
     supposed to start extension.
 | 
						||
 | 
						||
     Example:
 | 
						||
       nameFromURL "https://nixos.org/releases/nix/nix-1.7/nix-1.7-x86_64-linux.tar.bz2" "-"
 | 
						||
       => "nix"
 | 
						||
       nameFromURL "https://nixos.org/releases/nix/nix-1.7/nix-1.7-x86_64-linux.tar.bz2" "_"
 | 
						||
       => "nix-1.7-x86"
 | 
						||
  */
 | 
						||
  nameFromURL = url: sep:
 | 
						||
    let
 | 
						||
      components = splitString "/" url;
 | 
						||
      filename = lib.last components;
 | 
						||
      name = builtins.head (splitString sep filename);
 | 
						||
    in assert name != filename; name;
 | 
						||
 | 
						||
  /* Create an --{enable,disable}-<feat> string that can be passed to
 | 
						||
     standard GNU Autoconf scripts.
 | 
						||
 | 
						||
     Example:
 | 
						||
       enableFeature true "shared"
 | 
						||
       => "--enable-shared"
 | 
						||
       enableFeature false "shared"
 | 
						||
       => "--disable-shared"
 | 
						||
  */
 | 
						||
  enableFeature = enable: feat: "--${if enable then "enable" else "disable"}-${feat}";
 | 
						||
 | 
						||
  /* Create an --{enable-<feat>=<value>,disable-<feat>} string that can be passed to
 | 
						||
     standard GNU Autoconf scripts.
 | 
						||
 | 
						||
     Example:
 | 
						||
       enableFeature true "shared" "foo"
 | 
						||
       => "--enable-shared=foo"
 | 
						||
       enableFeature false "shared" (throw "ignored")
 | 
						||
       => "--disable-shared"
 | 
						||
  */
 | 
						||
  enableFeatureAs = enable: feat: value: enableFeature enable feat + optionalString enable "=${value}";
 | 
						||
 | 
						||
  /* Create an --{with,without}-<feat> string that can be passed to
 | 
						||
     standard GNU Autoconf scripts.
 | 
						||
 | 
						||
     Example:
 | 
						||
       withFeature true "shared"
 | 
						||
       => "--with-shared"
 | 
						||
       withFeature false "shared"
 | 
						||
       => "--without-shared"
 | 
						||
  */
 | 
						||
  withFeature = with_: feat: "--${if with_ then "with" else "without"}-${feat}";
 | 
						||
 | 
						||
  /* Create an --{with-<feat>=<value>,without-<feat>} string that can be passed to
 | 
						||
     standard GNU Autoconf scripts.
 | 
						||
 | 
						||
     Example:
 | 
						||
       with_Feature true "shared" "foo"
 | 
						||
       => "--with-shared=foo"
 | 
						||
       with_Feature false "shared" (throw "ignored")
 | 
						||
       => "--without-shared"
 | 
						||
  */
 | 
						||
  withFeatureAs = with_: feat: value: withFeature with_ feat + optionalString with_ "=${value}";
 | 
						||
 | 
						||
  /* Create a fixed width string with additional prefix to match
 | 
						||
     required width.
 | 
						||
 | 
						||
     This function will fail if the input string is longer than the
 | 
						||
     requested length.
 | 
						||
 | 
						||
     Type: fixedWidthString :: int -> string -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       fixedWidthString 5 "0" (toString 15)
 | 
						||
       => "00015"
 | 
						||
  */
 | 
						||
  fixedWidthString = width: filler: str:
 | 
						||
    let
 | 
						||
      strw = lib.stringLength str;
 | 
						||
      reqWidth = width - (lib.stringLength filler);
 | 
						||
    in
 | 
						||
      assert lib.assertMsg (strw <= width)
 | 
						||
        "fixedWidthString: requested string length (${
 | 
						||
          toString width}) must not be shorter than actual length (${
 | 
						||
            toString strw})";
 | 
						||
      if strw == width then str else filler + fixedWidthString reqWidth filler str;
 | 
						||
 | 
						||
  /* Format a number adding leading zeroes up to fixed width.
 | 
						||
 | 
						||
     Example:
 | 
						||
       fixedWidthNumber 5 15
 | 
						||
       => "00015"
 | 
						||
  */
 | 
						||
  fixedWidthNumber = width: n: fixedWidthString width "0" (toString n);
 | 
						||
 | 
						||
  /* Convert a float to a string, but emit a warning when precision is lost
 | 
						||
     during the conversion
 | 
						||
 | 
						||
     Example:
 | 
						||
       floatToString 0.000001
 | 
						||
       => "0.000001"
 | 
						||
       floatToString 0.0000001
 | 
						||
       => trace: warning: Imprecise conversion from float to string 0.000000
 | 
						||
          "0.000000"
 | 
						||
  */
 | 
						||
  floatToString = float: let
 | 
						||
    result = toString float;
 | 
						||
    precise = float == builtins.fromJSON result;
 | 
						||
  in if precise then result
 | 
						||
    else lib.warn "Imprecise conversion from float to string ${result}" result;
 | 
						||
 | 
						||
  /* Check whether a value can be coerced to a string */
 | 
						||
  isCoercibleToString = x:
 | 
						||
    builtins.elem (builtins.typeOf x) [ "path" "string" "null" "int" "float" "bool" ] ||
 | 
						||
    (builtins.isList x && lib.all isCoercibleToString x) ||
 | 
						||
    x ? outPath ||
 | 
						||
    x ? __toString;
 | 
						||
 | 
						||
  /* Check whether a value is a store path.
 | 
						||
 | 
						||
     Example:
 | 
						||
       isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11/bin/python"
 | 
						||
       => false
 | 
						||
       isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11/"
 | 
						||
       => true
 | 
						||
       isStorePath pkgs.python
 | 
						||
       => true
 | 
						||
       isStorePath [] || isStorePath 42 || isStorePath {} || …
 | 
						||
       => false
 | 
						||
  */
 | 
						||
  isStorePath = x:
 | 
						||
    if isCoercibleToString x then
 | 
						||
      let str = toString x; in
 | 
						||
      builtins.substring 0 1 str == "/"
 | 
						||
      && dirOf str == builtins.storeDir
 | 
						||
    else
 | 
						||
      false;
 | 
						||
 | 
						||
  /* Parse a string string as an int.
 | 
						||
 | 
						||
     Type: string -> int
 | 
						||
 | 
						||
     Example:
 | 
						||
       toInt "1337"
 | 
						||
       => 1337
 | 
						||
       toInt "-4"
 | 
						||
       => -4
 | 
						||
       toInt "3.14"
 | 
						||
       => error: floating point JSON numbers are not supported
 | 
						||
  */
 | 
						||
  # Obviously, it is a bit hacky to use fromJSON this way.
 | 
						||
  toInt = str:
 | 
						||
    let may_be_int = builtins.fromJSON str; in
 | 
						||
    if builtins.isInt may_be_int
 | 
						||
    then may_be_int
 | 
						||
    else throw "Could not convert ${str} to int.";
 | 
						||
 | 
						||
  /* Read a list of paths from `file`, relative to the `rootPath`.
 | 
						||
     Lines beginning with `#` are treated as comments and ignored.
 | 
						||
     Whitespace is significant.
 | 
						||
 | 
						||
     NOTE: This function is not performant and should be avoided.
 | 
						||
 | 
						||
     Example:
 | 
						||
       readPathsFromFile /prefix
 | 
						||
         ./pkgs/development/libraries/qt-5/5.4/qtbase/series
 | 
						||
       => [ "/prefix/dlopen-resolv.patch" "/prefix/tzdir.patch"
 | 
						||
            "/prefix/dlopen-libXcursor.patch" "/prefix/dlopen-openssl.patch"
 | 
						||
            "/prefix/dlopen-dbus.patch" "/prefix/xdg-config-dirs.patch"
 | 
						||
            "/prefix/nix-profiles-library-paths.patch"
 | 
						||
            "/prefix/compose-search-path.patch" ]
 | 
						||
  */
 | 
						||
  readPathsFromFile = lib.warn "lib.readPathsFromFile is deprecated, use a list instead"
 | 
						||
    (rootPath: file:
 | 
						||
      let
 | 
						||
        lines = lib.splitString "\n" (builtins.readFile file);
 | 
						||
        removeComments = lib.filter (line: line != "" && !(lib.hasPrefix "#" line));
 | 
						||
        relativePaths = removeComments lines;
 | 
						||
        absolutePaths = builtins.map (path: rootPath + "/${path}") relativePaths;
 | 
						||
      in
 | 
						||
        absolutePaths);
 | 
						||
 | 
						||
  /* Read the contents of a file removing the trailing \n
 | 
						||
 | 
						||
     Type: fileContents :: path -> string
 | 
						||
 | 
						||
     Example:
 | 
						||
       $ echo "1.0" > ./version
 | 
						||
 | 
						||
       fileContents ./version
 | 
						||
       => "1.0"
 | 
						||
  */
 | 
						||
  fileContents = file: removeSuffix "\n" (builtins.readFile file);
 | 
						||
 | 
						||
 | 
						||
  /* Creates a valid derivation name from a potentially invalid one.
 | 
						||
 | 
						||
     Type: sanitizeDerivationName :: String -> String
 | 
						||
 | 
						||
     Example:
 | 
						||
       sanitizeDerivationName "../hello.bar # foo"
 | 
						||
       => "-hello.bar-foo"
 | 
						||
       sanitizeDerivationName ""
 | 
						||
       => "unknown"
 | 
						||
       sanitizeDerivationName pkgs.hello
 | 
						||
       => "-nix-store-2g75chlbpxlrqn15zlby2dfh8hr9qwbk-hello-2.10"
 | 
						||
  */
 | 
						||
  sanitizeDerivationName = string: lib.pipe string [
 | 
						||
    # Get rid of string context. This is safe under the assumption that the
 | 
						||
    # resulting string is only used as a derivation name
 | 
						||
    builtins.unsafeDiscardStringContext
 | 
						||
    # Strip all leading "."
 | 
						||
    (x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0)
 | 
						||
    # Split out all invalid characters
 | 
						||
    # https://github.com/NixOS/nix/blob/2.3.2/src/libstore/store-api.cc#L85-L112
 | 
						||
    # https://github.com/NixOS/nix/blob/2242be83c61788b9c0736a92bb0b5c7bbfc40803/nix-rust/src/store/path.rs#L100-L125
 | 
						||
    (builtins.split "[^[:alnum:]+._?=-]+")
 | 
						||
    # Replace invalid character ranges with a "-"
 | 
						||
    (concatMapStrings (s: if lib.isList s then "-" else s))
 | 
						||
    # Limit to 211 characters (minus 4 chars for ".drv")
 | 
						||
    (x: substring (lib.max (stringLength x - 207) 0) (-1) x)
 | 
						||
    # If the result is empty, replace it with "unknown"
 | 
						||
    (x: if stringLength x == 0 then "unknown" else x)
 | 
						||
  ];
 | 
						||
 | 
						||
}
 |