Use GLOG_* environment variables even when gflags is installed.

Define GLOG_DEFINE_*, which checks if the GLOG_* environment variable
is defined. If defined, GLOG_DEFINE_* passes the value and otherwise,
it passes the original default value. In this way, GLOG_DEFINE_* macro
uses the value specified by gflags first, then GLOG_* environment
variables, and finally it uses the default value if neither of them are
specified.


git-svn-id: https://google-glog.googlecode.com/svn/trunk@76 eb4d4688-79bd-11dd-afb4-1d65580434c0

doc/glog.html

@@ -116,6 +116,13 @@ environment variables, prefixing the flag name with "GLOG_", e.g.
    GLOG_logtostderr=1 ./your_application
 </pre>
 
+<!-- TODO(hamaji): Fill the version number
+<p>By glog version 0.x.x, you can use GLOG_* environment variables
+even if you have gflags. If both an environment variable and a flag
+are specified, the value specified by a flag wins. E.g., if GLOG_v=0
+and --v=1, the verbosity will be 1, not 0.
+-->
+
 <p>The following flags are most commonly used:
 
 <dl>

src/base/commandlineflags.h

@@ -77,14 +77,13 @@
 #define DECLARE_bool(name) \
   DECLARE_VARIABLE(bool, name, bool)
 #define DEFINE_bool(name, value, meaning) \
-  DEFINE_VARIABLE(bool, name, EnvToBool("GLOG_" #name, value), meaning, bool)
+  DEFINE_VARIABLE(bool, name, value, meaning, bool)
 
 // int32 specialization
 #define DECLARE_int32(name) \
   DECLARE_VARIABLE(GOOGLE_NAMESPACE::int32, name, int32)
 #define DEFINE_int32(name, value, meaning) \
-  DEFINE_VARIABLE(GOOGLE_NAMESPACE::int32, name, \
-                  EnvToInt("GLOG_" #name, value), meaning, int32)
+  DEFINE_VARIABLE(GOOGLE_NAMESPACE::int32, name, value, meaning, int32)
 
 // Special case for string, because we have to specify the namespace
 // std::string, which doesn't play nicely with our FLAG__namespace hackery.
@@ -93,14 +92,31 @@
   extern GOOGLE_GLOG_DLL_DECL std::string FLAGS_##name;                       \
   }                                                                           \
   using FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead::FLAGS_##name
-#define DEFINE_string(name, value, meaning) \
+#define DEFINE_string(name, value, meaning)                                   \
   namespace FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead {  \
-  GOOGLE_GLOG_DLL_DECL std::string                                            \
-      FLAGS_##name(EnvToString("GLOG_" #name, value));                        \
+  GOOGLE_GLOG_DLL_DECL std::string FLAGS_##name(value);                       \
   char FLAGS_no##name;                                                        \
   }                                                                           \
   using FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead::FLAGS_##name
 
+#endif  // HAVE_LIB_GFLAGS
+
+// Define GLOG_DEFINE_* using DEFINE_* . By using these macros, we
+// have GLOG_* environ variables even if we have gflags installed.
+//
+// If both an environment variable and a flag are specified, the value
+// specified by a flag wins. E.g., if GLOG_v=0 and --v=1, the
+// verbosity will be 1, not 0.
+
+#define GLOG_DEFINE_bool(name, value, meaning) \
+  DEFINE_bool(name, EnvToBool("GLOG_" #name, value), meaning)
+
+#define GLOG_DEFINE_int32(name, value, meaning) \
+  DEFINE_int32(name, EnvToInt("GLOG_" #name, value), meaning)
+
+#define GLOG_DEFINE_string(name, value, meaning) \
+  DEFINE_string(name, EnvToString("GLOG_" #name, value), meaning)
+
 // These macros (could be functions, but I don't want to bother with a .cc
 // file), make it easier to initialize flags from the environment.
 
@@ -113,6 +129,4 @@
 #define EnvToInt(envname, dflt)  \
   (!getenv(envname) ? (dflt) : strtol(getenv(envname), NULL, 10))
 
-#endif  // HAVE_LIB_GFLAGS
-
 #endif  // BASE_COMMANDLINEFLAGS_H__

src/demangle_unittest.cc

@@ -41,7 +41,8 @@
 #include "googletest.h"
 #include "config.h"
 
-DEFINE_bool(demangle_filter, false, "Run demangle_unittest in filter mode");
+GLOG_DEFINE_bool(demangle_filter, false,
+                 "Run demangle_unittest in filter mode");
 
 using namespace std;
 using namespace GOOGLE_NAMESPACE;

src/logging.cc

@@ -89,15 +89,15 @@ static bool BoolFromEnv(const char *varname, bool defval) {
   return memchr("tTyY1\0", valstr[0], 6) != NULL;
 }
 
-DEFINE_bool(logtostderr, BoolFromEnv("GOOGLE_LOGTOSTDERR", false),
-            "log messages go to stderr instead of logfiles");
-DEFINE_bool(alsologtostderr, BoolFromEnv("GOOGLE_ALSOLOGTOSTDERR", false),
-            "log messages go to stderr in addition to logfiles");
+GLOG_DEFINE_bool(logtostderr, BoolFromEnv("GOOGLE_LOGTOSTDERR", false),
+                 "log messages go to stderr instead of logfiles");
+GLOG_DEFINE_bool(alsologtostderr, BoolFromEnv("GOOGLE_ALSOLOGTOSTDERR", false),
+                 "log messages go to stderr in addition to logfiles");
 #ifdef OS_LINUX
-DEFINE_bool(drop_log_memory, true, "Drop in-memory buffers of log contents. "
-            "Logs can grow very quickly and they are rarely read before they "
-            "need to be evicted from memory. Instead, drop them from memory "
-            "as soon as they are flushed to disk.");
+GLOG_DEFINE_bool(drop_log_memory, true, "Drop in-memory buffers of log contents. "
+                 "Logs can grow very quickly and they are rarely read before they "
+                 "need to be evicted from memory. Instead, drop them from memory "
+                 "as soon as they are flushed to disk.");
 _START_GOOGLE_NAMESPACE_
 namespace logging {
 static const int64 kPageSize = getpagesize();
@@ -115,25 +115,25 @@ DEFINE_int32(stderrthreshold,
              "log messages at or above this level are copied to stderr in "
              "addition to logfiles.  This flag obsoletes --alsologtostderr.");
 
-DEFINE_string(alsologtoemail, "",
-              "log messages go to these email addresses "
-              "in addition to logfiles");
-DEFINE_bool(log_prefix, true,
-            "Prepend the log prefix to the start of each log line");
-DEFINE_int32(minloglevel, 0, "Messages logged at a lower level than this don't "
-             "actually get logged anywhere");
-DEFINE_int32(logbuflevel, 0,
-             "Buffer log messages logged at this level or lower"
-             " (-1 means don't buffer; 0 means buffer INFO only;"
-             " ...)");
-DEFINE_int32(logbufsecs, 30,
-             "Buffer log messages for at most this many seconds");
-DEFINE_int32(logemaillevel, 999,
-             "Email log messages logged at this level or higher"
-             " (0 means email all; 3 means email FATAL only;"
-             " ...)");
-DEFINE_string(logmailer, "/bin/mail",
-              "Mailer used to send logging email");
+GLOG_DEFINE_string(alsologtoemail, "",
+                   "log messages go to these email addresses "
+                   "in addition to logfiles");
+GLOG_DEFINE_bool(log_prefix, true,
+                 "Prepend the log prefix to the start of each log line");
+GLOG_DEFINE_int32(minloglevel, 0, "Messages logged at a lower level than this don't "
+                  "actually get logged anywhere");
+GLOG_DEFINE_int32(logbuflevel, 0,
+                  "Buffer log messages logged at this level or lower"
+                  " (-1 means don't buffer; 0 means buffer INFO only;"
+                  " ...)");
+GLOG_DEFINE_int32(logbufsecs, 30,
+                  "Buffer log messages for at most this many seconds");
+GLOG_DEFINE_int32(logemaillevel, 999,
+                  "Email log messages logged at this level or higher"
+                  " (0 means email all; 3 means email FATAL only;"
+                  " ...)");
+GLOG_DEFINE_string(logmailer, "/bin/mail",
+                   "Mailer used to send logging email");
 
 // Compute the default value for --log_dir
 static const char* DefaultLogDir() {
@@ -149,21 +149,21 @@ static const char* DefaultLogDir() {
   return "";
 }
 
-DEFINE_string(log_dir, DefaultLogDir(),
-              "If specified, logfiles are written into this directory instead "
-              "of the default logging directory.");
-DEFINE_string(log_link, "", "Put additional links to the log "
-              "files in this directory");
+GLOG_DEFINE_string(log_dir, DefaultLogDir(),
+                   "If specified, logfiles are written into this directory instead "
+                   "of the default logging directory.");
+GLOG_DEFINE_string(log_link, "", "Put additional links to the log "
+                   "files in this directory");
 
-DEFINE_int32(max_log_size, 1800,
-             "approx. maximum log file size (in MB). A value of 0 will "
-             "be silently overridden to 1.");
+GLOG_DEFINE_int32(max_log_size, 1800,
+                  "approx. maximum log file size (in MB). A value of 0 will "
+                  "be silently overridden to 1.");
 
-DEFINE_bool(stop_logging_if_full_disk, false,
-            "Stop attempting to log to disk if the disk is full.");
+GLOG_DEFINE_bool(stop_logging_if_full_disk, false,
+                 "Stop attempting to log to disk if the disk is full.");
 
-DEFINE_string(log_backtrace_at, "",
-              "Emit a backtrace when logging at file:linenum.");
+GLOG_DEFINE_string(log_backtrace_at, "",
+                   "Emit a backtrace when logging at file:linenum.");
 
 // TODO(hamaji): consider windows
 #define PATH_SEPARATOR '/'

src/utilities.cc

@@ -63,8 +63,8 @@ _END_GOOGLE_NAMESPACE_
 #include "symbolize.h"
 #include "base/commandlineflags.h"
 
-DEFINE_bool(symbolize_stacktrace, true,
-            "Symbolize the stack trace in the tombstone");
+GLOG_DEFINE_bool(symbolize_stacktrace, true,
+                 "Symbolize the stack trace in the tombstone");
 
 _START_GOOGLE_NAMESPACE_
 

src/vlog_is_on.cc

@@ -49,10 +49,10 @@
 
 using std::string;
 
-DEFINE_int32(v, 0, "Show all VLOG(m) messages for m <= this."
+GLOG_DEFINE_int32(v, 0, "Show all VLOG(m) messages for m <= this."
 " Overridable by --vmodule.");
 
-DEFINE_string(vmodule, "", "per-module verbose level."
+GLOG_DEFINE_string(vmodule, "", "per-module verbose level."
 " Argument is a comma-separated list of <module name>=<log level>."
 " <module name> is a glob pattern, matched against the filename base"
 " (that is, name ignoring .cc/.h./-inl.h)."