michael@0: # This Source Code Form is subject to the terms of the Mozilla Public
michael@0: # License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: # file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0: 
michael@0: # Write out histogram information for C++.  The histograms are defined
michael@0: # in a file provided as a command-line argument.
michael@0: 
michael@0: from __future__ import with_statement
michael@0: 
michael@0: import sys
michael@0: import histogram_tools
michael@0: import itertools
michael@0: 
michael@0: banner = """/* This file is auto-generated, see gen-histogram-data.py.  */
michael@0: """
michael@0: 
michael@0: # Write out the gHistograms array.
michael@0: 
michael@0: class StringTable:
michael@0:     def __init__(self):
michael@0:         self.current_index = 0;
michael@0:         self.table = {}
michael@0: 
michael@0:     def c_strlen(self, string):
michael@0:         return len(string) + 1
michael@0: 
michael@0:     def stringIndex(self, string):
michael@0:         if string in self.table:
michael@0:             return self.table[string]
michael@0:         else:
michael@0:             result = self.current_index
michael@0:             self.table[string] = result
michael@0:             self.current_index += self.c_strlen(string)
michael@0:             return result
michael@0: 
michael@0:     def writeDefinition(self, f, name):
michael@0:         entries = self.table.items()
michael@0:         entries.sort(key=lambda x:x[1])
michael@0:         # Avoid null-in-string warnings with GCC and potentially
michael@0:         # overlong string constants; write everything out the long way.
michael@0:         def explodeToCharArray(string):
michael@0:             def toCChar(s):
michael@0:                 if s == "'":
michael@0:                     return "'\\''"
michael@0:                 else:
michael@0:                     return "'%s'" % s
michael@0:             return ", ".join(map(toCChar, string))
michael@0:         f.write("const char %s[] = {\n" % name)
michael@0:         for (string, offset) in entries[:-1]:
michael@0:             e = explodeToCharArray(string)
michael@0:             if e:
michael@0:                 f.write("  /* %5d */ %s, '\\0',\n"
michael@0:                         % (offset, explodeToCharArray(string)))
michael@0:             else:
michael@0:                 f.write("  /* %5d */ '\\0',\n" % offset)
michael@0:         f.write("  /* %5d */ %s, '\\0' };\n\n"
michael@0:                 % (entries[-1][1], explodeToCharArray(entries[-1][0])))
michael@0: 
michael@0: def print_array_entry(histogram, name_index, exp_index):
michael@0:     cpp_guard = histogram.cpp_guard()
michael@0:     if cpp_guard:
michael@0:         print "#if defined(%s)" % cpp_guard
michael@0:     print "  { %s, %s, %s, %s, %d, %d, %s }," \
michael@0:         % (histogram.low(), histogram.high(),
michael@0:            histogram.n_buckets(), histogram.nsITelemetry_kind(),
michael@0:            name_index, exp_index,
michael@0:            "true" if histogram.extended_statistics_ok() else "false")
michael@0:     if cpp_guard:
michael@0:         print "#endif"
michael@0: 
michael@0: def write_histogram_table(histograms):
michael@0:     table = StringTable()
michael@0: 
michael@0:     print "const TelemetryHistogram gHistograms[] = {"
michael@0:     for histogram in histograms:
michael@0:         name_index = table.stringIndex(histogram.name())
michael@0:         exp_index = table.stringIndex(histogram.expiration())
michael@0:         print_array_entry(histogram, name_index, exp_index)
michael@0:     print "};"
michael@0: 
michael@0:     strtab_name = "gHistogramStringTable"
michael@0:     table.writeDefinition(sys.stdout, strtab_name)
michael@0:     static_assert("sizeof(%s) <= UINT32_MAX" % strtab_name,
michael@0:                   "index overflow")
michael@0: 
michael@0: # Write out static asserts for histogram data.  We'd prefer to perform
michael@0: # these checks in this script itself, but since several histograms
michael@0: # (generally enumerated histograms) use compile-time constants for
michael@0: # their upper bounds, we have to let the compiler do the checking.
michael@0: 
michael@0: def static_assert(expression, message):
michael@0:     print "static_assert(%s, \"%s\");" % (expression, message)
michael@0: 
michael@0: def static_asserts_for_boolean(histogram):
michael@0:     pass
michael@0: 
michael@0: def static_asserts_for_flag(histogram):
michael@0:     pass
michael@0: 
michael@0: def static_asserts_for_enumerated(histogram):
michael@0:     n_values = histogram.high()
michael@0:     static_assert("%s > 2" % n_values,
michael@0:                   "Not enough values for %s" % histogram.name())
michael@0: 
michael@0: def shared_static_asserts(histogram):
michael@0:     name = histogram.name()
michael@0:     low = histogram.low()
michael@0:     high = histogram.high()
michael@0:     n_buckets = histogram.n_buckets()
michael@0:     static_assert("%s < %s" % (low, high), "low >= high for %s" % name)
michael@0:     static_assert("%s > 2" % n_buckets, "Not enough values for %s" % name)
michael@0:     static_assert("%s >= 1" % low, "Incorrect low value for %s" % name)
michael@0:     static_assert("%s > %s" % (high, n_buckets),
michael@0:                   "high must be > number of buckets for %s; you may want an enumerated histogram" % name)
michael@0: 
michael@0: def static_asserts_for_linear(histogram):
michael@0:     shared_static_asserts(histogram)
michael@0: 
michael@0: def static_asserts_for_exponential(histogram):
michael@0:     shared_static_asserts(histogram)
michael@0: 
michael@0: def write_histogram_static_asserts(histograms):
michael@0:     print """
michael@0: // Perform the checks at the beginning of HistogramGet at
michael@0: // compile time, so that incorrect histogram definitions
michael@0: // give compile-time errors, not runtime errors."""
michael@0: 
michael@0:     table = {
michael@0:         'boolean' : static_asserts_for_boolean,
michael@0:         'flag' : static_asserts_for_flag,
michael@0:         'enumerated' : static_asserts_for_enumerated,
michael@0:         'linear' : static_asserts_for_linear,
michael@0:         'exponential' : static_asserts_for_exponential,
michael@0:         }
michael@0: 
michael@0:     for histogram in histograms:
michael@0:         histogram_tools.table_dispatch(histogram.kind(), table,
michael@0:                                        lambda f: f(histogram))
michael@0: 
michael@0: def write_debug_histogram_ranges(histograms):
michael@0:     ranges_lengths = []
michael@0: 
michael@0:     # Collect all the range information from individual histograms.
michael@0:     # Write that information out as well.
michael@0:     print "#ifdef DEBUG"
michael@0:     print "const int gBucketLowerBounds[] = {"
michael@0:     for histogram in histograms:
michael@0:         ranges = []
michael@0:         try:
michael@0:             ranges = histogram.ranges()
michael@0:         except histogram_tools.DefinitionException:
michael@0:             pass
michael@0:         ranges_lengths.append(len(ranges))
michael@0:         # Note that we do not test cpp_guard here.  We do this so we
michael@0:         # will have complete information about all the histograms in
michael@0:         # this array.  Just having information about the ranges of
michael@0:         # histograms is not platform-specific; if there are histograms
michael@0:         # that have platform-specific constants in their definitions,
michael@0:         # those histograms will fail in the .ranges() call above and
michael@0:         # we'll have a zero-length array to deal with here.
michael@0:         if len(ranges) > 0:
michael@0:             print ','.join(map(str, ranges)), ','
michael@0:         else:
michael@0:             print '/* Skipping %s */' % histogram.name()
michael@0:     print "};"
michael@0: 
michael@0:     # Write the offsets into gBucketLowerBounds.
michael@0:     print "struct bounds { int offset; int length; };"
michael@0:     print "const struct bounds gBucketLowerBoundIndex[] = {"
michael@0:     offset = 0
michael@0:     for (histogram, range_length) in itertools.izip(histograms, ranges_lengths):
michael@0:         cpp_guard = histogram.cpp_guard()
michael@0:         # We do test cpp_guard here, so that histogram IDs are valid
michael@0:         # indexes into this array.
michael@0:         if cpp_guard:
michael@0:             print "#if defined(%s)" % cpp_guard
michael@0:         print "{ %d, %d }," % (offset, range_length)
michael@0:         if cpp_guard:
michael@0:             print "#endif"
michael@0:         offset += range_length
michael@0:     print "};"
michael@0:     print "#endif"
michael@0: 
michael@0: def main(argv):
michael@0:     filename = argv[0]
michael@0: 
michael@0:     histograms = list(histogram_tools.from_file(filename))
michael@0: 
michael@0:     print banner
michael@0:     write_histogram_table(histograms)
michael@0:     write_histogram_static_asserts(histograms)
michael@0:     write_debug_histogram_ranges(histograms)
michael@0: 
michael@0: main(sys.argv[1:])