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// file : libbuild2/make-parser.hxx -*- C++ -*-
// license : MIT; see accompanying LICENSE file
#ifndef LIBBUILD2_MAKE_PARSER_HXX
#define LIBBUILD2_MAKE_PARSER_HXX
#include <libbuild2/types.hxx>
#include <libbuild2/utility.hxx>
#include <libbuild2/export.hxx>
namespace build2
{
// Make dependency declaration parser.
//
// The format is line-based (but with potential line continuations) so we
// parse one line at a time. This allows the caller to bail out early (for
// example, on encountering a non-existent generated file).
//
class LIBBUILD2_SYMEXPORT make_parser
{
public:
enum {begin, targets, prereqs, end} state = begin;
// Parse next target/prerequisite on a line starting from the specified
// position. Update the position to point to the start of the following
// target/prerequisite or line.size() if there is nothing left on this
// line. May return an empty path for a valid if unlikely dependency
// declarations (see below) or if passing leading blank lines (both of
// which should normally be just skipped). Issue diagnostics and throw
// failed if the declaration or path is invalid.
//
// If strict is false, then allow unescaped `:` in prerequisites.
//
// Note that the (pos != line.size) should be in the do-while rather than
// in a while loop. In other words, except for the leading blank lines,
// the parser needs to see the blank line to correctly identify the end of
// the declaration. See make-parser.test.cxx for a recommended usage.
//
// To parse more than one declaration, reset the state to begin after
// reaching end.
//
enum class type {target, prereq};
pair<type, path>
next (const string& line, size_t& pos, const location&, bool strict);
// Lower-level stateless API.
//
public:
// Parse next target/prerequisite on a line starting from the specified
// position. Return the target/prerequisite as well as an indication of
// whether the end of the dependency declaration was reached. Update the
// position to point to the start of the following target/prerequisite,
// `:`, or line.size() if there is nothing left on this line.
//
// Note that some broken tools (notably MinGW GCC) do not escape `:`
// properly. To tolerate such cases the caller may specify that what's
// being parsed is the prerequisite list in which case unescaped `:` will
// be treated literally.
//
// Note also that this function may return an empty string (with
// end=false) for a valid if unlikely dependency declaration, for example
// (using | to represent backslash):
//
// foo:|
// |
// bar
//
// It would also return an empty string (with end=true) if passed and
// empty or whitespace-only line.
//
// Note also that in the make language line continuations introduce a
// whitespace rather than just being remove. For example, the following
// declaration has two prerequisites:
//
// foo: bar|
// baz
//
static pair<string, bool>
next (const string& line, size_t& pos, optional<bool> prereq = nullopt);
};
}
#endif // LIBBUILD2_MAKE_PARSER_HXX
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