Infrastructure for an extension C-library to implement sqlite3_db_dump() and

a corresponding "dbdump" command-line utility - both of which do the same
work as the ".dump" command of the CLI.

FossilOrigin-Name: 74c5ace498f72d7f5495203678bedd0bc540211131a4e4db7b62115d5322a288

1 files changed, 103 insertions, 0 deletions

diff --git a/ext/misc/dbdump.c b/ext/misc/dbdump.c
new file mode 100644
index 000000000..b7fe595e2
--- /dev/null
+++ b/ext/misc/dbdump.c
@@ -0,0 +1,103 @@
+/*
+** 2016-03-13
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements a C-language subroutine that converts the content
+** of an SQLite database into UTF-8 text SQL statements that can be used
+** to exactly recreate the original database.
+**
+** A prototype of the implemented subroutine is this:
+**
+**   int sqlite3_db_dump(
+**          sqlite3 *db,
+**          const char *zSchema,
+**          const char *zTable,
+**          void (*xCallback)(void*, const char*),
+**          void *pArg
+**   );
+**
+** The db parameter is the database connection.  zSchema is the schema within
+** that database which is to be dumped.  Usually the zSchema is "main" but
+** can also be "temp" or any ATTACH-ed database.  If zTable is not NULL, then
+** only the content of that one table is dumped.  If zTable is NULL, then all
+** tables are dumped.
+**
+** The generate text is passed to xCallback() in multiple calls.  The second
+** argument to xCallback() is a copy of the pArg parameter.  The first
+** argument is some of the output text that this routine generates.  The
+** signature to xCallback() is designed to make it compatible with fputs().
+**
+** The sqlite3_db_dump() subroutine returns SQLITE_OK on success or some error
+** code if it encounters a problem.
+**
+** If this file is compiled with -DDBDUMP_STANDALONE then a "main()" routine
+** is included so that this routine becomes a command-line utility.  The
+** command-line utility takes two or three arguments which are the name
+** of the database file, the schema, and optionally the table, forming the
+** first three arguments of a single call to the library routine.
+*/
+#include "sqlite3.h"
+
+/*
+** Convert an SQLite database into SQL statements that will recreate that
+** database.
+*/
+int sqlite3_db_dump(
+  sqlite3 *db,               /* The database connection */
+  const char *zSchema,       /* Which schema to dump.  Usually "main". */
+  const char *zTable,        /* Which table to dump.  NULL means everything. */
+  int (*xCallback)(const char*,void*),   /* Output sent to this callback */
+  void *pArg                             /* Second argument of the callback */
+){
+  return SQLITE_OK;
+}
+
+
+
+/* The generic subroutine is above.  The code the follows implements
+** the command-line interface.
+*/
+#ifdef DBDUMP_STANDALONE
+#include <stdio.h>
+
+/*
+** Command-line interface
+*/
+int main(int argc, char **argv){
+  sqlite3 *db;
+  const char *zDb;
+  const char *zSchema;
+  const char *zTable = 0;
+  int rc;
+
+  if( argc<2 || argc>4 ){
+    fprintf(stderr, "Usage: %s DATABASE ?SCHEMA? ?TABLE?\n", argv[0]);
+    return 1;
+  }
+  zDb = argv[1];
+  zSchema = argc>=3 ? argv[2] : "main";
+  zTable = argc==4 ? argv[3] : 0;
+
+  rc = sqlite3_open(zDb, &db);
+  if( rc ){
+    fprintf(stderr, "Cannot open \"%s\": %s\n", zDb, sqlite3_errmsg(db));
+    sqlite3_close(db);
+    return 1;
+  }
+  rc = sqlite3_db_dump(db, zSchema, zTable, 
+          (int(*)(const char*,void*))fputs, (void*)stdout);
+  if( rc ){
+    fprintf(stderr, "Error: sqlite3_db_dump() returns %d\n", rc);
+  }
+  sqlite3_close(db);
+  return rc!=SQLITE_OK;  
+}
+#endif /* DBDUMP_STANDALONE */