From: dan <dan@noemail.net>
Date: Thu, 10 Dec 2015 20:03:08 +0000 (+0000)
Subject: Update the sqlite3_snapshot_get() API so that if the caller does not have an open... 
X-Git-Tag: version-3.10.0~44^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7116dc60dc1017472e254a4e475a13c621996e6d;p=thirdparty%2Fsqlite.git

Update the sqlite3_snapshot_get() API so that if the caller does not have an open read transaction on the named database, one is automatically opened.

FossilOrigin-Name: b9c90f10297d8516a661449e8af898e682c930aa
---

diff --git a/manifest b/manifest
index c962225c27..8387bc5312 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\stests\sto\ssnapshot.test.
-D 2015-12-10T19:44:34.237
+C Update\sthe\ssqlite3_snapshot_get()\sAPI\sso\sthat\sif\sthe\scaller\sdoes\snot\shave\san\sopen\sread\stransaction\son\sthe\snamed\sdatabase,\sone\sis\sautomatically\sopened.
+D 2015-12-10T20:03:08.672
 F Makefile.in 28bcd6149e050dff35d4dcfd97e890cd387a499d
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc e8fdca1cb89a1b58b5f4d3a130ea9a3d28cb314d
@@ -304,7 +304,7 @@ F src/insert.c e1d20ae8979e25519c2670233718676bedcfedc9
 F src/journal.c b4124532212b6952f42eb2c12fa3c25701d8ba8d
 F src/legacy.c ba1863ea58c4c840335a84ec276fc2b25e22bc4e
 F src/loadext.c 84996d7d70a605597d79c1f1d7b2012a5fd34f2b
-F src/main.c 3dc84d9bd722fb16c196a867d39acf86b8f72b70
+F src/main.c 2f33510a6a392c606fe64964e695e55ad124242f
 F src/malloc.c 337bbe9c7d436ef9b7d06b5dd10bbfc8f3025972
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c 6919bcf12f221868ea066eec27e579fed95ce98b
@@ -341,7 +341,7 @@ F src/resolve.c a83b41104e6ff69855d03cd0aaa09e93927ec39f
 F src/rowset.c eccf6af6d620aaa4579bd3b72c1b6395d9e9fa1e
 F src/select.c f8fded11fc443a9f5a73cc5db069d06b34460e2f
 F src/shell.c abbc74ea43dbf2f306ea18282d666683fb5efab2
-F src/sqlite.h.in 19dea4862ccfcc1a733d0fd18d4744b02a505ac6
+F src/sqlite.h.in fa2c9d85cb144fad389864f9e40c4f59336d31ed
 F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
 F src/sqlite3ext.h dfbe62ffd95b99afe2140d8c35b180d11924072d
 F src/sqliteInt.h 5caacf37a776f9d6178e519cb0b5248ca22a3828
@@ -1020,7 +1020,7 @@ F test/skipscan2.test d1d1450952b7275f0b0a3a981f0230532743951a
 F test/skipscan3.test ec5bab3f81c7038b43450e7b3062e04a198bdbb5
 F test/skipscan5.test 67817a4b6857c47e0e33ba3e506da6f23ef68de2
 F test/skipscan6.test 5866039d03a56f5bd0b3d172a012074a1d90a15b
-F test/snapshot.test 62983ac46f05b898d5317a8d1b91a7bd8a355988
+F test/snapshot.test bfcf728577d674d85b7da4bc69786ecafd2acebe
 F test/snapshot_fault.test 06472056c516be4610834de4688ea3357e8bde01
 F test/soak.test 0b5b6375c9f4110c828070b826b3b4b0bb65cd5f
 F test/softheap1.test 843cd84db9891b2d01b9ab64cef3e9020f98d087
@@ -1410,7 +1410,7 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 5343060bcc6c99029f731f8020d2cba3f405f207
-R cf3f8934dbec5c5165c0ac82e4a8ba25
+P f3b743623a4501833478c8a86c0922931955aeb6
+R 50bb5d50d586d96f69cac8095fa25e56
 U dan
-Z 7e377350f279588c8392c3c3e03a4f17
+Z 07077a92d084d80e6cdd7a283dbdc283
diff --git a/manifest.uuid b/manifest.uuid
index 7a16425ff5..3dacbbd066 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-f3b743623a4501833478c8a86c0922931955aeb6
\ No newline at end of file
+b9c90f10297d8516a661449e8af898e682c930aa
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 902954b60d..5b2130511e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3891,10 +3891,11 @@ int sqlite3_snapshot_get(
   iDb = sqlite3FindDbName(db, zDb);
   if( iDb==0 || iDb>1 ){
     Btree *pBt = db->aDb[iDb].pBt;
-    if( 0!=sqlite3BtreeIsInReadTrans(pBt) 
-     && 0==sqlite3BtreeIsInTrans(pBt)
-    ){
-      rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
+    if( 0==sqlite3BtreeIsInTrans(pBt) ){
+      rc = sqlite3BtreeBeginTrans(pBt, 0);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
+      }
     }
   }
 
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 601415b907..8dcf99eb2a 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -7883,8 +7883,10 @@ int sqlite3_db_cacheflush(sqlite3*);
 **
 ** The second argument passed to sqlite3_snapshot_get() must be the name
 ** of a database file attached to the database handle passed as the first.
-** The database handle must have an open read transaction on the named 
-** database, which must be in wal mode. 
+** The database handle must not have an open write transaction on the named 
+** database, which must be in wal mode. If the database handle does not
+** have an open read transaction on the named file, this function opens
+** one.
 **
 ** If successful, sqlite3_snapshot_get() sets *ppSnapshot to point to a new
 ** snapshot handle that may be used with sqlite3_snapshot_open() and returns
diff --git a/test/snapshot.test b/test/snapshot.test
index 37af5b8e04..a01ac5a754 100644
--- a/test/snapshot.test
+++ b/test/snapshot.test
@@ -19,9 +19,8 @@ set testprefix snapshot
 #-------------------------------------------------------------------------
 # Check some error conditions in snapshot_get(). It is an error if:
 #
-#  1) snapshot_get() is called on a non-WAL database.
-#  2) there is no open read transaction on the database, or
-#  3) there is an open write transaction on the database.
+#  1) snapshot_get() is called on a non-WAL database, or
+#  2) there is an open write transaction on the database.
 #
 do_execsql_test 1.0 {
   CREATE TABLE t1(a, b);
@@ -37,15 +36,9 @@ do_execsql_test 1.1.2 COMMIT
 
 do_test 1.2.1 {
   execsql {
-    PRAGMA journal_mode = wal;
-    INSERT INTO t1 VALUES(5, 6);
-  }
-  list [catch { sqlite3_snapshot_get db main } msg] $msg
-} {1 SQLITE_ERROR}
-
-do_test 1.3.1 {
-  execsql {
+    PRAGMA journal_mode = WAL;
     BEGIN;
+      INSERT INTO t1 VALUES(5, 6);
       INSERT INTO t1 VALUES(7, 8);
   }
   list [catch { sqlite3_snapshot_get db main } msg] $msg
@@ -61,6 +54,7 @@ do_execsql_test 2.1.0 {
     SELECT * FROM t1;
 } {1 2 3 4 5 6 7 8}
 
+breakpoint
 do_test 2.1.1 {
   set snapshot [sqlite3_snapshot_get db main]
   execsql {
@@ -114,6 +108,31 @@ do_test 2.2.3 {
   db2 close
 } {}
 
+do_test 2.3.1 {
+  execsql { DELETE FROM t1 WHERE a>6 }
+  set snapshot [sqlite3_snapshot_get db main]
+  execsql {
+    INSERT INTO t1 VALUES('a', 'b');
+    INSERT INTO t1 VALUES('c', 'd');
+    SELECT * FROM t1;
+  }
+} {1 2 3 4 5 6 a b c d}
+do_test 2.3.2 {
+  execsql BEGIN
+  sqlite3_snapshot_open db main $snapshot
+  execsql { SELECT * FROM t1 }
+} {1 2 3 4 5 6}
+
+do_test 2.3.3 {
+  catchsql {
+    INSERT INTO t1 VALUES('x','y')
+  }
+} {1 {database is locked}}
+do_test 2.3.4 {
+  execsql COMMIT
+  sqlite3_snapshot_free $snapshot
+} {}
+
 #-------------------------------------------------------------------------
 # Check some errors in sqlite3_snapshot_open(). It is an error if:
 #