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Diffstat (limited to 'libbuild2/make-parser.cxx')
| -rw-r--r-- | libbuild2/make-parser.cxx | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/libbuild2/make-parser.cxx b/libbuild2/make-parser.cxx new file mode 100644 index 0000000..c6c077f --- /dev/null +++ b/libbuild2/make-parser.cxx @@ -0,0 +1,171 @@ +// file : libbuild2/make-parser.cxx -*- C++ -*- +// license : MIT; see accompanying LICENSE file + +#include <libbuild2/make-parser.hxx> + +#include <cstring> // strchr() + +#include <libbuild2/diagnostics.hxx> + +namespace build2 +{ + auto make_parser:: + next (const string& l, size_t& p, const location& ll) -> pair<type, path> + { + assert (state != end); + + type t (state == prereqs ? type::prereq : type::target); + + pair<string, bool> r (next (l, p, t)); + + // Deal with the end. + // + if (r.second) + { + if (state == begin && r.first.empty ()) + ; // Skip leading blank line. + else + { + if (state != prereqs) + fail (ll) << "end of make dependency declaration before ':'"; + + state = end; + } + } + // Deal with the first target. + // + else if (state == begin && !r.first.empty ()) + state = targets; + + // Deal with `:`. + // + if (p != l.size () && l[p] == ':') + { + switch (state) + { + case begin: fail (ll) << "':' before make target"; break; + case targets: state = prereqs; break; + case prereqs: fail (ll) << "':' after make prerequisite"; break; + case end: break; + } + + if (++p == l.size ()) + state = end; // Not a mere optimization: the caller will get next line. + } + + try + { + return pair<type, path> (t, path (move (r.first))); + } + catch (const invalid_path& e) + { + fail (ll) << "invalid make " + << (t == type::prereq ? "prerequisite" : "target") + << " path '" << e.path << "'" << endf; + } + } + + // Note: backslash must be first. + // + // Note also that, at least in GNU make 4.1, `%` seems to be unescapable + // if appears in a target and literal if in a prerequisite. + // + static const char escapable[] = "\\ :#"; + + pair<string, bool> make_parser:: + next (const string& l, size_t& p, type) + { + size_t n (l.size ()); + + // Skip leading spaces. + // + for (; p != n && l[p] == ' '; p++) ; + + // Lines containing multiple targets/prerequisites are customarily 80 + // characters max. + // + string r; + r.reserve (n - p); + + // Scan the next target/prerequisite while watching out for escape + // sequences. + // + // @@ Can't we do better for the (common) case where nothing is escaped? + // +#ifdef _WIN32 + size_t b (p); +#endif + + for (char c; p != n && (c = l[p]) != ' '; r += c) + { + if (c == ':') + { +#ifdef _WIN32 + // See if this colon is part of the driver letter component in an + // absolute Windows path. + // + // Note that here we assume we are not dealing with directories (in + // which case c: would be a valid path) and thus an absolute path is + // at least 4 characters long (e.g., c:\x). + // + if (p == b + 1 && // Colon is second character. + alpha (l[b]) && // First is drive letter. + p + 2 < n && // At least two more characters after colon. + ((l[p + 1] == '/') || // Next is directory separator. + (l[p + 1] == '\\' && // But not part of a non-\\ escape sequence. + strchr (escapable + 1, l[p + 2]) == nullptr))) + { + ++p; + continue; + } +#endif + break; + } + + // If we have another character, then handle the escapes. + // + if (++p != n) + { + if (c == '\\') + { + // This may or may not be an escape sequence depending on whether + // what follows is "escapable". + // + if (strchr (escapable, l[p]) != nullptr) + c = l[p++]; + } + else if (c == '$') + { + // Got to be another (escaped) '$'. + // + if (l[p] == '$') + ++p; + } + } + // Note that the newline escape is not necessarily separated with space. + // + else if (c == '\\') + { + --p; + break; + } + } + + // Skip trailing spaces. + // + for (; p != n && l[p] == ' '; p++) ; + + // Skip final '\' and determine if this is the end. + // + bool e (false); + if (p == n - 1) + { + if (l[p] == '\\') + p++; + } + else if (p == n) + e = true; + + return pair<string, bool> (move (r), e); + } +} |