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-rw-r--r--src/third_party/linux/include/gflags/gflags.h533
-rw-r--r--src/third_party/linux/include/gflags/gflags_completions.h121
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diff --git a/src/third_party/linux/include/gflags/gflags.h b/src/third_party/linux/include/gflags/gflags.h
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+// Copyright (c) 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Ray Sidney
+// Revamped and reorganized by Craig Silverstein
+//
+// This is the file that should be included by any file which declares
+// or defines a command line flag or wants to parse command line flags
+// or print a program usage message (which will include information about
+// flags). Executive summary, in the form of an example foo.cc file:
+//
+// #include "foo.h" // foo.h has a line "DECLARE_int32(start);"
+//
+// DEFINE_int32(end, 1000, "The last record to read");
+// DECLARE_bool(verbose); // some other file has a DEFINE_bool(verbose, ...)
+//
+// void MyFunc() {
+// if (FLAGS_verbose) printf("Records %d-%d\n", FLAGS_start, FLAGS_end);
+// }
+//
+// Then, at the command-line:
+// ./foo --noverbose --start=5 --end=100
+//
+// For more details, see
+// doc/gflags.html
+//
+// --- A note about thread-safety:
+//
+// We describe many functions in this routine as being thread-hostile,
+// thread-compatible, or thread-safe. Here are the meanings we use:
+//
+// thread-safe: it is safe for multiple threads to call this routine
+// (or, when referring to a class, methods of this class)
+// concurrently.
+// thread-hostile: it is not safe for multiple threads to call this
+// routine (or methods of this class) concurrently. In gflags,
+// most thread-hostile routines are intended to be called early in,
+// or even before, main() -- that is, before threads are spawned.
+// thread-compatible: it is safe for multiple threads to read from
+// this variable (when applied to variables), or to call const
+// methods of this class (when applied to classes), as long as no
+// other thread is writing to the variable or calling non-const
+// methods of this class.
+
+#ifndef GOOGLE_GFLAGS_H_
+#define GOOGLE_GFLAGS_H_
+
+#include <string>
+#include <vector>
+
+// We care a lot about number of bits things take up. Unfortunately,
+// systems define their bit-specific ints in a lot of different ways.
+// We use our own way, and have a typedef to get there.
+// Note: these commands below may look like "#if 1" or "#if 0", but
+// that's because they were constructed that way at ./configure time.
+// Look at gflags.h.in to see how they're calculated (based on your config).
+#if 1
+#include <stdint.h> // the normal place uint16_t is defined
+#endif
+#if 1
+#include <sys/types.h> // the normal place u_int16_t is defined
+#endif
+#if 1
+#include <inttypes.h> // a third place for uint16_t or u_int16_t
+#endif
+
+namespace google {
+
+#if 1 // the C99 format
+typedef int32_t int32;
+typedef uint32_t uint32;
+typedef int64_t int64;
+typedef uint64_t uint64;
+#elif 1 // the BSD format
+typedef int32_t int32;
+typedef u_int32_t uint32;
+typedef int64_t int64;
+typedef u_int64_t uint64;
+#elif 0 // the windows (vc7) format
+typedef __int32 int32;
+typedef unsigned __int32 uint32;
+typedef __int64 int64;
+typedef unsigned __int64 uint64;
+#else
+#error Do not know how to define a 32-bit integer quantity on your system
+#endif
+
+// --------------------------------------------------------------------
+// To actually define a flag in a file, use DEFINE_bool,
+// DEFINE_string, etc. at the bottom of this file. You may also find
+// it useful to register a validator with the flag. This ensures that
+// when the flag is parsed from the commandline, or is later set via
+// SetCommandLineOption, we call the validation function.
+//
+// The validation function should return true if the flag value is valid, and
+// false otherwise. If the function returns false for the new setting of the
+// flag, the flag will retain its current value. If it returns false for the
+// default value, InitGoogle will die.
+//
+// This function is safe to call at global construct time (as in the
+// example below).
+//
+// Example use:
+// static bool ValidatePort(const char* flagname, int32 value) {
+// if (value > 0 && value < 32768) // value is ok
+// return true;
+// printf("Invalid value for --%s: %d\n", flagname, (int)value);
+// return false;
+// }
+// DEFINE_int32(port, 0, "What port to listen on");
+// static bool dummy = RegisterFlagValidator(&FLAGS_port, &ValidatePort);
+
+// Returns true if successfully registered, false if not (because the
+// first argument doesn't point to a command-line flag, or because a
+// validator is already registered for this flag).
+bool RegisterFlagValidator(const bool* flag,
+ bool (*validate_fn)(const char*, bool));
+bool RegisterFlagValidator(const int32* flag,
+ bool (*validate_fn)(const char*, int32));
+bool RegisterFlagValidator(const int64* flag,
+ bool (*validate_fn)(const char*, int64));
+bool RegisterFlagValidator(const uint64* flag,
+ bool (*validate_fn)(const char*, uint64));
+bool RegisterFlagValidator(const double* flag,
+ bool (*validate_fn)(const char*, double));
+bool RegisterFlagValidator(const std::string* flag,
+ bool (*validate_fn)(const char*, const std::string&));
+
+
+// --------------------------------------------------------------------
+// These methods are the best way to get access to info about the
+// list of commandline flags. Note that these routines are pretty slow.
+// GetAllFlags: mostly-complete info about the list, sorted by file.
+// ShowUsageWithFlags: pretty-prints the list to stdout (what --help does)
+// ShowUsageWithFlagsRestrict: limit to filenames with restrict as a substr
+//
+// In addition to accessing flags, you can also access argv[0] (the program
+// name) and argv (the entire commandline), which we sock away a copy of.
+// These variables are static, so you should only set them once.
+
+struct CommandLineFlagInfo {
+ std::string name; // the name of the flag
+ std::string type; // the type of the flag: int32, etc
+ std::string description; // the "help text" associated with the flag
+ std::string current_value; // the current value, as a string
+ std::string default_value; // the default value, as a string
+ std::string filename; // 'cleaned' version of filename holding the flag
+ bool has_validator_fn; // true if RegisterFlagValidator called on flag
+ bool is_default; // true if the flag has default value
+};
+
+extern void GetAllFlags(std::vector<CommandLineFlagInfo>* OUTPUT);
+// These two are actually defined in commandlineflags_reporting.cc.
+extern void ShowUsageWithFlags(const char *argv0); // what --help does
+extern void ShowUsageWithFlagsRestrict(const char *argv0, const char *restrict);
+
+// Create a descriptive string for a flag.
+// Goes to some trouble to make pretty line breaks.
+extern std::string DescribeOneFlag(const CommandLineFlagInfo& flag);
+
+// Thread-hostile; meant to be called before any threads are spawned.
+extern void SetArgv(int argc, const char** argv);
+// The following functions are thread-safe as long as SetArgv() is
+// only called before any threads start.
+extern const std::vector<std::string>& GetArgvs(); // all of argv as a vector
+extern const char* GetArgv(); // all of argv as a string
+extern const char* GetArgv0(); // only argv0
+extern uint32 GetArgvSum(); // simple checksum of argv
+extern const char* ProgramInvocationName(); // argv0, or "UNKNOWN" if not set
+extern const char* ProgramInvocationShortName(); // basename(argv0)
+// ProgramUsage() is thread-safe as long as SetUsageMessage() is only
+// called before any threads start.
+extern const char* ProgramUsage(); // string set by SetUsageMessage()
+
+
+// --------------------------------------------------------------------
+// Normally you access commandline flags by just saying "if (FLAGS_foo)"
+// or whatever, and set them by calling "FLAGS_foo = bar" (or, more
+// commonly, via the DEFINE_foo macro). But if you need a bit more
+// control, we have programmatic ways to get/set the flags as well.
+// These programmatic ways to access flags are thread-safe, but direct
+// access is only thread-compatible.
+
+// Return true iff the flagname was found.
+// OUTPUT is set to the flag's value, or unchanged if we return false.
+extern bool GetCommandLineOption(const char* name, std::string* OUTPUT);
+
+// Return true iff the flagname was found. OUTPUT is set to the flag's
+// CommandLineFlagInfo or unchanged if we return false.
+extern bool GetCommandLineFlagInfo(const char* name,
+ CommandLineFlagInfo* OUTPUT);
+
+// Return the CommandLineFlagInfo of the flagname. exit() if name not found.
+// Example usage, to check if a flag's value is currently the default value:
+// if (GetCommandLineFlagInfoOrDie("foo").is_default) ...
+extern CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const char* name);
+
+enum FlagSettingMode {
+ // update the flag's value (can call this multiple times).
+ SET_FLAGS_VALUE,
+ // update the flag's value, but *only if* it has not yet been updated
+ // with SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef".
+ SET_FLAG_IF_DEFAULT,
+ // set the flag's default value to this. If the flag has not yet updated
+ // yet (via SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef")
+ // change the flag's current value to the new default value as well.
+ SET_FLAGS_DEFAULT
+};
+
+// Set a particular flag ("command line option"). Returns a string
+// describing the new value that the option has been set to. The
+// return value API is not well-specified, so basically just depend on
+// it to be empty if the setting failed for some reason -- the name is
+// not a valid flag name, or the value is not a valid value -- and
+// non-empty else.
+
+// SetCommandLineOption uses set_mode == SET_FLAGS_VALUE (the common case)
+extern std::string SetCommandLineOption(const char* name, const char* value);
+extern std::string SetCommandLineOptionWithMode(const char* name, const char* value,
+ FlagSettingMode set_mode);
+
+
+// --------------------------------------------------------------------
+// Saves the states (value, default value, whether the user has set
+// the flag, registered validators, etc) of all flags, and restores
+// them when the FlagSaver is destroyed. This is very useful in
+// tests, say, when you want to let your tests change the flags, but
+// make sure that they get reverted to the original states when your
+// test is complete.
+//
+// Example usage:
+// void TestFoo() {
+// FlagSaver s1;
+// FLAG_foo = false;
+// FLAG_bar = "some value";
+//
+// // test happens here. You can return at any time
+// // without worrying about restoring the FLAG values.
+// }
+//
+// Note: This class is marked with __attribute__((unused)) because all the
+// work is done in the constructor and destructor, so in the standard
+// usage example above, the compiler would complain that it's an
+// unused variable.
+//
+// This class is thread-safe.
+
+class FlagSaver {
+ public:
+ FlagSaver();
+ ~FlagSaver();
+
+ private:
+ class FlagSaverImpl* impl_; // we use pimpl here to keep API steady
+
+ FlagSaver(const FlagSaver&); // no copying!
+ void operator=(const FlagSaver&);
+} __attribute__ ((unused));
+
+// --------------------------------------------------------------------
+// Some deprecated or hopefully-soon-to-be-deprecated functions.
+
+// This is often used for logging. TODO(csilvers): figure out a better way
+extern std::string CommandlineFlagsIntoString();
+// Usually where this is used, a FlagSaver should be used instead.
+extern bool ReadFlagsFromString(const std::string& flagfilecontents,
+ const char* prog_name,
+ bool errors_are_fatal); // uses SET_FLAGS_VALUE
+
+// These let you manually implement --flagfile functionality.
+// DEPRECATED.
+extern bool AppendFlagsIntoFile(const std::string& filename, const char* prog_name);
+extern bool SaveCommandFlags(); // actually defined in google.cc !
+extern bool ReadFromFlagsFile(const std::string& filename, const char* prog_name,
+ bool errors_are_fatal); // uses SET_FLAGS_VALUE
+
+
+// --------------------------------------------------------------------
+// Useful routines for initializing flags from the environment.
+// In each case, if 'varname' does not exist in the environment
+// return defval. If 'varname' does exist but is not valid
+// (e.g., not a number for an int32 flag), abort with an error.
+// Otherwise, return the value. NOTE: for booleans, for true use
+// 't' or 'T' or 'true' or '1', for false 'f' or 'F' or 'false' or '0'.
+
+extern bool BoolFromEnv(const char *varname, bool defval);
+extern int32 Int32FromEnv(const char *varname, int32 defval);
+extern int64 Int64FromEnv(const char *varname, int64 defval);
+extern uint64 Uint64FromEnv(const char *varname, uint64 defval);
+extern double DoubleFromEnv(const char *varname, double defval);
+extern const char *StringFromEnv(const char *varname, const char *defval);
+
+
+// --------------------------------------------------------------------
+// The next two functions parse commandlineflags from main():
+
+// Set the "usage" message for this program. For example:
+// string usage("This program does nothing. Sample usage:\n");
+// usage += argv[0] + " <uselessarg1> <uselessarg2>";
+// SetUsageMessage(usage);
+// Do not include commandline flags in the usage: we do that for you!
+// Thread-hostile; meant to be called before any threads are spawned.
+extern void SetUsageMessage(const std::string& usage);
+
+// Looks for flags in argv and parses them. Rearranges argv to put
+// flags first, or removes them entirely if remove_flags is true.
+// If a flag is defined more than once in the command line or flag
+// file, the last definition is used.
+// See top-of-file for more details on this function.
+#ifndef SWIG // In swig, use ParseCommandLineFlagsScript() instead.
+extern uint32 ParseCommandLineFlags(int *argc, char*** argv,
+ bool remove_flags);
+#endif
+
+
+// Calls to ParseCommandLineNonHelpFlags and then to
+// HandleCommandLineHelpFlags can be used instead of a call to
+// ParseCommandLineFlags during initialization, in order to allow for
+// changing default values for some FLAGS (via
+// e.g. SetCommandLineOptionWithMode calls) between the time of
+// command line parsing and the time of dumping help information for
+// the flags as a result of command line parsing.
+// If a flag is defined more than once in the command line or flag
+// file, the last definition is used.
+extern uint32 ParseCommandLineNonHelpFlags(int *argc, char*** argv,
+ bool remove_flags);
+// This is actually defined in commandlineflags_reporting.cc.
+// This function is misnamed (it also handles --version, etc.), but
+// it's too late to change that now. :-(
+extern void HandleCommandLineHelpFlags(); // in commandlineflags_reporting.cc
+
+// Allow command line reparsing. Disables the error normally
+// generated when an unknown flag is found, since it may be found in a
+// later parse. Thread-hostile; meant to be called before any threads
+// are spawned.
+extern void AllowCommandLineReparsing();
+
+// Reparse the flags that have not yet been recognized.
+// Only flags registered since the last parse will be recognized.
+// Any flag value must be provided as part of the argument using "=",
+// not as a separate command line argument that follows the flag argument.
+// Intended for handling flags from dynamically loaded libraries,
+// since their flags are not registered until they are loaded.
+extern uint32 ReparseCommandLineNonHelpFlags();
+
+
+// --------------------------------------------------------------------
+// Now come the command line flag declaration/definition macros that
+// will actually be used. They're kind of hairy. A major reason
+// for this is initialization: we want people to be able to access
+// variables in global constructors and have that not crash, even if
+// their global constructor runs before the global constructor here.
+// (Obviously, we can't guarantee the flags will have the correct
+// default value in that case, but at least accessing them is safe.)
+// The only way to do that is have flags point to a static buffer.
+// So we make one, using a union to ensure proper alignment, and
+// then use placement-new to actually set up the flag with the
+// correct default value. In the same vein, we have to worry about
+// flag access in global destructors, so FlagRegisterer has to be
+// careful never to destroy the flag-values it constructs.
+//
+// Note that when we define a flag variable FLAGS_<name>, we also
+// preemptively define a junk variable, FLAGS_no<name>. This is to
+// cause a link-time error if someone tries to define 2 flags with
+// names like "logging" and "nologging". We do this because a bool
+// flag FLAG can be set from the command line to true with a "-FLAG"
+// argument, and to false with a "-noFLAG" argument, and so this can
+// potentially avert confusion.
+//
+// We also put flags into their own namespace. It is purposefully
+// named in an opaque way that people should have trouble typing
+// directly. The idea is that DEFINE puts the flag in the weird
+// namespace, and DECLARE imports the flag from there into the current
+// namespace. The net result is to force people to use DECLARE to get
+// access to a flag, rather than saying "extern bool FLAGS_whatever;"
+// or some such instead. We want this so we can put extra
+// functionality (like sanity-checking) in DECLARE if we want, and
+// make sure it is picked up everywhere.
+//
+// We also put the type of the variable in the namespace, so that
+// people can't DECLARE_int32 something that they DEFINE_bool'd
+// elsewhere.
+
+class FlagRegisterer {
+ public:
+ FlagRegisterer(const char* name, const char* type,
+ const char* help, const char* filename,
+ void* current_storage, void* defvalue_storage);
+};
+
+extern bool FlagsTypeWarn(const char *name);
+
+// If your application #defines STRIP_FLAG_HELP to a non-zero value
+// before #including this file, we remove the help message from the
+// binary file. This can reduce the size of the resulting binary
+// somewhat, and may also be useful for security reasons.
+
+extern const char kStrippedFlagHelp[];
+
+}
+
+#ifndef SWIG // In swig, ignore the main flag declarations
+
+#if defined(STRIP_FLAG_HELP) && STRIP_FLAG_HELP > 0
+// Need this construct to avoid the 'defined but not used' warning.
+#define MAYBE_STRIPPED_HELP(txt) (false ? (txt) : kStrippedFlagHelp)
+#else
+#define MAYBE_STRIPPED_HELP(txt) txt
+#endif
+
+// Each command-line flag has two variables associated with it: one
+// with the current value, and one with the default value. However,
+// we have a third variable, which is where value is assigned; it's a
+// constant. This guarantees that FLAG_##value is initialized at
+// static initialization time (e.g. before program-start) rather than
+// than global construction time (which is after program-start but
+// before main), at least when 'value' is a compile-time constant. We
+// use a small trick for the "default value" variable, and call it
+// FLAGS_no<name>. This serves the second purpose of assuring a
+// compile error if someone tries to define a flag named no<name>
+// which is illegal (--foo and --nofoo both affect the "foo" flag).
+#define DEFINE_VARIABLE(type, shorttype, name, value, help) \
+ namespace fL##shorttype { \
+ static const type FLAGS_nono##name = value; \
+ type FLAGS_##name = FLAGS_nono##name; \
+ type FLAGS_no##name = FLAGS_nono##name; \
+ static ::google::FlagRegisterer o_##name( \
+ #name, #type, MAYBE_STRIPPED_HELP(help), __FILE__, \
+ &FLAGS_##name, &FLAGS_no##name); \
+ } \
+ using fL##shorttype::FLAGS_##name
+
+#define DECLARE_VARIABLE(type, shorttype, name) \
+ namespace fL##shorttype { \
+ extern type FLAGS_##name; \
+ } \
+ using fL##shorttype::FLAGS_##name
+
+// For DEFINE_bool, we want to do the extra check that the passed-in
+// value is actually a bool, and not a string or something that can be
+// coerced to a bool. These declarations (no definition needed!) will
+// help us do that, and never evaluate From, which is important.
+// We'll use 'sizeof(IsBool(val))' to distinguish. This code requires
+// that the compiler have different sizes for bool & double. Since
+// this is not guaranteed by the standard, we check it with a
+// compile-time assert (msg[-1] will give a compile-time error).
+namespace fLB {
+struct CompileAssert {};
+typedef CompileAssert expected_sizeof_double_neq_sizeof_bool[
+ (sizeof(double) != sizeof(bool)) ? 1 : -1];
+template<typename From> double IsBoolFlag(const From& from);
+bool IsBoolFlag(bool from);
+} // namespace fLB
+
+#define DECLARE_bool(name) DECLARE_VARIABLE(bool,B, name)
+#define DEFINE_bool(name,val,txt) \
+ namespace fLB { \
+ typedef CompileAssert FLAG_##name##_value_is_not_a_bool[ \
+ (sizeof(::fLB::IsBoolFlag(val)) != sizeof(double)) ? 1 : -1]; \
+ } \
+ DEFINE_VARIABLE(bool,B, name, val, txt)
+
+#define DECLARE_int32(name) DECLARE_VARIABLE(::google::int32,I, name)
+#define DEFINE_int32(name,val,txt) DEFINE_VARIABLE(::google::int32,I, name, val, txt)
+
+#define DECLARE_int64(name) DECLARE_VARIABLE(::google::int64,I64, name)
+#define DEFINE_int64(name,val,txt) DEFINE_VARIABLE(::google::int64,I64, name, val, txt)
+
+#define DECLARE_uint64(name) DECLARE_VARIABLE(::google::uint64,U64, name)
+#define DEFINE_uint64(name,val,txt) DEFINE_VARIABLE(::google::uint64,U64, name, val, txt)
+
+#define DECLARE_double(name) DECLARE_VARIABLE(double,D, name)
+#define DEFINE_double(name,val,txt) DEFINE_VARIABLE(double,D, name, val, txt)
+
+// Strings are trickier, because they're not a POD, so we can't
+// construct them at static-initialization time (instead they get
+// constructed at global-constructor time, which is much later). To
+// try to avoid crashes in that case, we use a char buffer to store
+// the string, which we can static-initialize, and then placement-new
+// into it later. It's not perfect, but the best we can do.
+#define DECLARE_string(name) namespace fLS { extern std::string& FLAGS_##name; } \
+ using fLS::FLAGS_##name
+
+// We need to define a var named FLAGS_no##name so people don't define
+// --string and --nostring. And we need a temporary place to put val
+// so we don't have to evaluate it twice. Two great needs that go
+// great together!
+// The weird 'using' + 'extern' inside the fLS namespace is to work around
+// an unknown compiler bug/issue with the gcc 4.2.1 on SUSE 10. See
+// http://code.google.com/p/google-gflags/issues/detail?id=20
+#define DEFINE_string(name, val, txt) \
+ namespace fLS { \
+ static union { void* align; char s[sizeof(std::string)]; } s_##name[2]; \
+ const std::string* const FLAGS_no##name = new (s_##name[0].s) std::string(val); \
+ static ::google::FlagRegisterer o_##name( \
+ #name, "string", MAYBE_STRIPPED_HELP(txt), __FILE__, \
+ s_##name[0].s, new (s_##name[1].s) std::string(*FLAGS_no##name)); \
+ extern std::string& FLAGS_##name; \
+ using fLS::FLAGS_##name; \
+ std::string& FLAGS_##name = *(reinterpret_cast<std::string*>(s_##name[0].s)); \
+ } \
+ using fLS::FLAGS_##name
+
+#endif // SWIG
+
+#endif // GOOGLE_GFLAGS_H_
diff --git a/src/third_party/linux/include/gflags/gflags_completions.h b/src/third_party/linux/include/gflags/gflags_completions.h
new file mode 100644
index 00000000..9d9ce7a5
--- /dev/null
+++ b/src/third_party/linux/include/gflags/gflags_completions.h
@@ -0,0 +1,121 @@
+// Copyright (c) 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// ---
+// Author: Dave Nicponski
+//
+// Implement helpful bash-style command line flag completions
+//
+// ** Functional API:
+// HandleCommandLineCompletions() should be called early during
+// program startup, but after command line flag code has been
+// initialized, such as the beginning of HandleCommandLineHelpFlags().
+// It checks the value of the flag --tab_completion_word. If this
+// flag is empty, nothing happens here. If it contains a string,
+// however, then HandleCommandLineCompletions() will hijack the
+// process, attempting to identify the intention behind this
+// completion. Regardless of the outcome of this deduction, the
+// process will be terminated, similar to --helpshort flag
+// handling.
+//
+// ** Overview of Bash completions:
+// Bash can be told to programatically determine completions for the
+// current 'cursor word'. It does this by (in this case) invoking a
+// command with some additional arguments identifying the command
+// being executed, the word being completed, and the previous word
+// (if any). Bash then expects a sequence of output lines to be
+// printed to stdout. If these lines all contain a common prefix
+// longer than the cursor word, bash will replace the cursor word
+// with that common prefix, and display nothing. If there isn't such
+// a common prefix, bash will display the lines in pages using 'more'.
+//
+// ** Strategy taken for command line completions:
+// If we can deduce either the exact flag intended, or a common flag
+// prefix, we'll output exactly that. Otherwise, if information
+// must be displayed to the user, we'll take the opportunity to add
+// some helpful information beyond just the flag name (specifically,
+// we'll include the default flag value and as much of the flag's
+// description as can fit on a single terminal line width, as specified
+// by the flag --tab_completion_columns). Furthermore, we'll try to
+// make bash order the output such that the most useful or relevent
+// flags are the most likely to be shown at the top.
+//
+// ** Additional features:
+// To assist in finding that one really useful flag, substring matching
+// was implemented. Before pressing a <TAB> to get completion for the
+// current word, you can append one or more '?' to the flag to do
+// substring matching. Here's the semantics:
+// --foo<TAB> Show me all flags with names prefixed by 'foo'
+// --foo?<TAB> Show me all flags with 'foo' somewhere in the name
+// --foo??<TAB> Same as prior case, but also search in module
+// definition path for 'foo'
+// --foo???<TAB> Same as prior case, but also search in flag
+// descriptions for 'foo'
+// Finally, we'll trim the output to a relatively small number of
+// flags to keep bash quiet about the verbosity of output. If one
+// really wanted to see all possible matches, appending a '+' to the
+// search word will force the exhaustive list of matches to be printed.
+//
+// ** How to have bash accept completions from a binary:
+// Bash requires that it be informed about each command that programmatic
+// completion should be enabled for. Example addition to a .bashrc
+// file would be (your path to gflags_completions.sh file may differ):
+
+/*
+$ complete -o bashdefault -o default -o nospace -C \
+ '/usr/local/bin/gflags_completions.sh --tab_completion_columns $COLUMNS' \
+ time env binary_name another_binary [...]
+*/
+
+// This would allow the following to work:
+// $ /path/to/binary_name --vmodule<TAB>
+// Or:
+// $ ./bin/path/another_binary --gfs_u<TAB>
+// (etc)
+//
+// Sadly, it appears that bash gives no easy way to force this behavior for
+// all commands. That's where the "time" in the above example comes in.
+// If you haven't specifically added a command to the list of completion
+// supported commands, you can still get completions by prefixing the
+// entire command with "env".
+// $ env /some/brand/new/binary --vmod<TAB>
+// Assuming that "binary" is a newly compiled binary, this should still
+// produce the expected completion output.
+
+
+#ifndef GOOGLE_GFLAGS_COMPLETIONS_H_
+#define GOOGLE_GFLAGS_COMPLETIONS_H_
+
+namespace google {
+
+void HandleCommandLineCompletions(void);
+
+}
+
+#endif // GOOGLE_GFLAGS_COMPLETIONS_H_