Add large object functions catering to SQL callers.

With these, one need no longer manipulate large object descriptors and
extract numeric constants from header files in order to read and write
large object contents from SQL.

Pavel Stehule, reviewed by Rushabh Lathia.

3 files changed, 121 insertions, 0 deletions

diff --git a/src/test/regress/input/largeobject.source b/src/test/regress/input/largeobject.source
index f0ea7a2e173..996304ba79b 100644
--- a/src/test/regress/input/largeobject.source
+++ b/src/test/regress/input/largeobject.source
@@ -203,5 +203,26 @@ SELECT pageno, data FROM pg_largeobject WHERE loid = :newloid;
 SELECT lo_unlink(loid) FROM lotest_stash_values;
 \lo_unlink :newloid
 
+\lo_import 'results/lotest.txt'
+
+\set newloid_1 :LASTOID
+
+SELECT lo_create(0, lo_get(:newloid_1)) AS newloid_2
+\gset
+
+SELECT md5(lo_get(:newloid_1)) = md5(lo_get(:newloid_2));
+
+SELECT lo_get(:newloid_1, 0, 20);
+SELECT lo_get(:newloid_1, 10, 20);
+SELECT lo_put(:newloid_1, 5, decode('afafafaf', 'hex'));
+SELECT lo_get(:newloid_1, 0, 20);
+
+SELECT lo_put(:newloid_1, 4294967310, 'foo');
+SELECT lo_get(:newloid_1);
+SELECT lo_get(:newloid_1, 4294967294, 100);
+
+\lo_unlink :newloid_1
+\lo_unlink :newloid_2
+
 TRUNCATE lotest_stash_values;
 DROP ROLE regresslo;
diff --git a/src/test/regress/output/largeobject.source b/src/test/regress/output/largeobject.source
index a25ac2a9125..e6dd97e700b 100644
--- a/src/test/regress/output/largeobject.source
+++ b/src/test/regress/output/largeobject.source
@@ -391,5 +391,55 @@ SELECT lo_unlink(loid) FROM lotest_stash_values;
 (1 row)
 
 \lo_unlink :newloid
+\lo_import 'results/lotest.txt'
+\set newloid_1 :LASTOID
+SELECT lo_create(0, lo_get(:newloid_1)) AS newloid_2
+\gset
+SELECT md5(lo_get(:newloid_1)) = md5(lo_get(:newloid_2));
+ ?column? 
+----------
+ t
+(1 row)
+
+SELECT lo_get(:newloid_1, 0, 20);
+                  lo_get                   
+-------------------------------------------
+ 8800\0110\0110\0110\0110\0110\0110\011800
+(1 row)
+
+SELECT lo_get(:newloid_1, 10, 20);
+                  lo_get                   
+-------------------------------------------
+ \0110\0110\0110\011800\011800\0113800\011
+(1 row)
+
+SELECT lo_put(:newloid_1, 5, decode('afafafaf', 'hex'));
+ lo_put 
+--------
+ 
+(1 row)
+
+SELECT lo_get(:newloid_1, 0, 20);
+                     lo_get                      
+-------------------------------------------------
+ 8800\011\257\257\257\2570\0110\0110\0110\011800
+(1 row)
+
+SELECT lo_put(:newloid_1, 4294967310, 'foo');
+ lo_put 
+--------
+ 
+(1 row)
+
+SELECT lo_get(:newloid_1);
+ERROR:  large object read request is too large
+SELECT lo_get(:newloid_1, 4294967294, 100);
+                               lo_get                                
+---------------------------------------------------------------------
+ \000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000foo
+(1 row)
+
+\lo_unlink :newloid_1
+\lo_unlink :newloid_2
 TRUNCATE lotest_stash_values;
 DROP ROLE regresslo;
diff --git a/src/test/regress/output/largeobject_1.source b/src/test/regress/output/largeobject_1.source
index bae74f6c268..8665822a678 100644
--- a/src/test/regress/output/largeobject_1.source
+++ b/src/test/regress/output/largeobject_1.source
@@ -391,5 +391,55 @@ SELECT lo_unlink(loid) FROM lotest_stash_values;
 (1 row)
 
 \lo_unlink :newloid
+\lo_import 'results/lotest.txt'
+\set newloid_1 :LASTOID
+SELECT lo_create(0, lo_get(:newloid_1)) AS newloid_2
+\gset
+SELECT md5(lo_get(:newloid_1)) = md5(lo_get(:newloid_2));
+ ?column? 
+----------
+ t
+(1 row)
+
+SELECT lo_get(:newloid_1, 0, 20);
+                  lo_get                   
+-------------------------------------------
+ 8800\0110\0110\0110\0110\0110\0110\011800
+(1 row)
+
+SELECT lo_get(:newloid_1, 10, 20);
+                  lo_get                   
+-------------------------------------------
+ \0110\0110\0110\011800\011800\0113800\011
+(1 row)
+
+SELECT lo_put(:newloid_1, 5, decode('afafafaf', 'hex'));
+ lo_put 
+--------
+ 
+(1 row)
+
+SELECT lo_get(:newloid_1, 0, 20);
+                     lo_get                      
+-------------------------------------------------
+ 8800\011\257\257\257\2570\0110\0110\0110\011800
+(1 row)
+
+SELECT lo_put(:newloid_1, 4294967310, 'foo');
+ lo_put 
+--------
+ 
+(1 row)
+
+SELECT lo_get(:newloid_1);
+ERROR:  large object read request is too large
+SELECT lo_get(:newloid_1, 4294967294, 100);
+                               lo_get                                
+---------------------------------------------------------------------
+ \000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000foo
+(1 row)
+
+\lo_unlink :newloid_1
+\lo_unlink :newloid_2
 TRUNCATE lotest_stash_values;
 DROP ROLE regresslo;