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Diffstat (limited to 'libbuild2/make-parser.hxx')
-rw-r--r-- | libbuild2/make-parser.hxx | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/libbuild2/make-parser.hxx b/libbuild2/make-parser.hxx new file mode 100644 index 0000000..f6da7a1 --- /dev/null +++ b/libbuild2/make-parser.hxx @@ -0,0 +1,83 @@ +// 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). + // + // Note that most tools (MinGW GCC, Qt moc, etc) do not escape `:` in + // absolute Windows paths. To handle such cases the parser recognizes `:` + // that is a part of the driver letter component and does not treat it as + // the target/prerequisite separator. + // + 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. + // + // 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&); + + // 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 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 an 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, type); + }; +} + +#endif // LIBBUILD2_MAKE_PARSER_HXX |