Make extra calls to sqlite3_shutdown() be harmless no-ops. (CVS 6520)

FossilOrigin-Name: d80822953c2d2f2fd7f6acdd3caa403c0decacc4
diff --git a/manifest b/manifest
index 701e713..8497c6a 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Revise\sthe\simplementation\sof\ssqlite3_initialize()\sslightly\sin\sorder\sto\smake\nit\smore\seasily\stestable.\s\sThe\sfunctionality\sshould\sbe\sunchanged.\s(CVS\s6519)
-D 2009-04-17T16:54:23
+C Make\sextra\scalls\sto\ssqlite3_shutdown()\sbe\sharmless\sno-ops.\s(CVS\s6520)
+D 2009-04-19T12:23:58
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -122,7 +122,7 @@
 F src/journal.c e00df0c0da8413ab6e1bb7d7cab5665d4a9000d0
 F src/legacy.c 2ad5b52df322d0f132f66817095e0e79c8942611
 F src/loadext.c 3f96631089fc4f3871a67f02f2e4fc7ea4d51edc
-F src/main.c b1eac85b643cae84217874e78a73d1ccf0718b00
+F src/main.c 1c68b1be781915d713d07262353c074854cd707f
 F src/malloc.c a1f0f8ae110abb8eb546e259ab0eaea7e0f9b588
 F src/mem0.c f2f84062d1f35814d6535c9f9e33de3bfb3b132c
 F src/mem1.c e6d5c23941288df8191b8a98c28e3f57771e2270
@@ -157,7 +157,7 @@
 F src/rowset.c badb9f36b3a2ced9ee9551f4ce730f5fab442791
 F src/select.c 35225756c247484f473678e5bd191d70a6e4dba0
 F src/shell.c 0a11f831603f17fea20ca97133c0f64e716af4a7
-F src/sqlite.h.in 1537d33b86d022f53a97009e2a0e2229badc23cf
+F src/sqlite.h.in 4a12a7193d4dcceef4f2c6a42a4b8c51f6ccd412
 F src/sqlite3ext.h 1db7d63ab5de4b3e6b83dd03d1a4e64fef6d2a17
 F src/sqliteInt.h fcdad0896da9c8b6372db974131e33b7a06606ce
 F src/sqliteLimit.h ffe93f5a0c4e7bd13e70cd7bf84cfb5c3465f45d
@@ -717,7 +717,7 @@
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 97c6ea2368556b2a9a914ba2322085e312598b15
-R 41ba3a8408b6d435c1e0e58bca724f55
+P bb1a390a3d2f79b27e3ec2514ae00f5b22dbfb06
+R bfe81c34d0885c2bfee07a323015841e
 U drh
-Z d98b7bef780e2d16aa5f1f8b742918e9
+Z b04415dd5b051642fb17a59a62ddd487
diff --git a/manifest.uuid b/manifest.uuid
index f949c34..9bec9f7 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-bb1a390a3d2f79b27e3ec2514ae00f5b22dbfb06
\ No newline at end of file
+d80822953c2d2f2fd7f6acdd3caa403c0decacc4
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 6edaeee..a6cdefb 100644
--- a/src/main.c
+++ b/src/main.c
@@ -14,7 +14,7 @@
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
 **
-** $Id: main.c,v 1.537 2009/04/17 16:54:23 drh Exp $
+** $Id: main.c,v 1.538 2009/04/19 12:23:58 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -213,18 +213,22 @@
 ** Undo the effects of sqlite3_initialize().  Must not be called while
 ** there are outstanding database connections or memory allocations or
 ** while any part of SQLite is otherwise in use in any thread.  This
-** routine is not threadsafe.  Not by a long shot.
+** routine is not threadsafe.  But it is safe to invoke this routine
+** on when SQLite is already shut down.  If SQLite is already shut down
+** when this routine is invoked, then this routine is a harmless no-op.
 */
 int sqlite3_shutdown(void){
-  sqlite3GlobalConfig.isMallocInit = 0;
-  sqlite3PcacheShutdown();
   if( sqlite3GlobalConfig.isInit ){
-    sqlite3_os_end();
+    sqlite3GlobalConfig.isMallocInit = 0;
+    sqlite3PcacheShutdown();
+    if( sqlite3GlobalConfig.isInit ){
+      sqlite3_os_end();
+    }
+    sqlite3_reset_auto_extension();
+    sqlite3MallocEnd();
+    sqlite3MutexEnd();
+    sqlite3GlobalConfig.isInit = 0;
   }
-  sqlite3_reset_auto_extension();
-  sqlite3MallocEnd();
-  sqlite3MutexEnd();
-  sqlite3GlobalConfig.isInit = 0;
   return SQLITE_OK;
 }
 
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 9b5184c..440bc54 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -30,7 +30,7 @@
 ** the version number) and changes its name to "sqlite3.h" as
 ** part of the build process.
 **
-** @(#) $Id: sqlite.h.in,v 1.441 2009/04/13 14:43:41 drh Exp $
+** @(#) $Id: sqlite.h.in,v 1.442 2009/04/19 12:23:58 drh Exp $
 */
 #ifndef _SQLITE3_H_
 #define _SQLITE3_H_
@@ -791,6 +791,11 @@
 ** of sqlite3_initialize() does any initialization.  All other calls
 ** are harmless no-ops.
 **
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other calls to sqlite3_shutdown() are harmless no-ops.
+**
 ** Among other things, sqlite3_initialize() shall invoke
 ** sqlite3_os_init().  Similarly, sqlite3_shutdown()
 ** shall invoke sqlite3_os_end().