The Tor Browser: toolkit/components/telemetry/gen-histogram-data.py@b8a032363ba2 (annotated)

toolkit/components/telemetry/gen-histogram-data.py@b8a032363ba2 (annotated)

toolkit/components/telemetry/gen-histogram-data.py

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

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

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toolkit/components/telemetry/gen-histogram-data.py@b8a032363ba2 (annotated)

toolkit/components/telemetry/gen-histogram-data.py