Start of multi-DBMS support

1 files changed, 200 insertions, 0 deletions

diff --git a/src/postgres.sml b/src/postgres.sml
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+(* Copyright (c) 2008-2009, Adam Chlipala
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ * - The names of contributors may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *)
+
+structure Postgres :> POSTGRES = struct
+
+open Settings
+open Print.PD
+open Print
+
+fun init (dbstring, ss) =
+    box [if #persistent (currentProtocol ()) then
+             box [string "static void uw_db_prepare(uw_context ctx) {",
+                  newline,
+                  string "PGconn *conn = uw_get_db(ctx);",
+                  newline,
+                  string "PGresult *res;",
+                  newline,
+                  newline,
+
+                  p_list_sepi newline (fn i => fn (s, n) =>
+                                                  box [string "res = PQprepare(conn, \"uw",
+                                                       string (Int.toString i),
+                                                       string "\", \"",
+                                                       string (String.toString s),
+                                                       string "\", ",
+                                                       string (Int.toString n),
+                                                       string ", NULL);",
+                                                       newline,
+                                                       string "if (PQresultStatus(res) != PGRES_COMMAND_OK) {",
+                                                       newline,
+                                                       box [string "char msg[1024];",
+                                                            newline,
+                                                            string "strncpy(msg, PQerrorMessage(conn), 1024);",
+                                                            newline,
+                                                            string "msg[1023] = 0;",
+                                                            newline,
+                                                            string "PQclear(res);",
+                                                            newline,
+                                                            string "PQfinish(conn);",
+                                                            newline,
+                                                            string "uw_error(ctx, FATAL, \"Unable to create prepared statement:\\n",
+                                                            string (String.toString s),
+                                                            string "\\n%s\", msg);",
+                                                            newline],
+                                                       string "}",
+                                                       newline,
+                                                       string "PQclear(res);",
+                                                       newline])
+                              ss,
+
+                  string "}",
+                  newline,
+                  newline,
+
+                  string "void uw_db_close(uw_context ctx) {",
+                  newline,
+                  string "PQfinish(uw_get_db(ctx));",
+                  newline,
+                  string "}",
+                  newline,
+                  newline,
+
+                  string "int uw_db_begin(uw_context ctx) {",
+                  newline,
+                  string "PGconn *conn = uw_get_db(ctx);",
+                  newline,
+                  string "PGresult *res = PQexec(conn, \"BEGIN ISOLATION LEVEL SERIALIZABLE\");",
+                  newline,
+                  newline,
+                  string "if (res == NULL) return 1;",
+                  newline,
+                  newline,
+                  string "if (PQresultStatus(res) != PGRES_COMMAND_OK) {",
+                  box [string "PQclear(res);",
+                       newline,
+                       string "return 1;",
+                       newline],
+                  string "}",
+                  newline,
+                  string "return 0;",
+                  newline,
+                  string "}",
+                  newline,
+                  newline,
+
+                  string "int uw_db_commit(uw_context ctx) {",
+                  newline,
+                  string "PGconn *conn = uw_get_db(ctx);",
+                  newline,
+                  string "PGresult *res = PQexec(conn, \"COMMIT\");",
+                  newline,
+                  newline,
+                  string "if (res == NULL) return 1;",
+                  newline,
+                  newline,
+                  string "if (PQresultStatus(res) != PGRES_COMMAND_OK) {",
+                  box [string "PQclear(res);",
+                       newline,
+                       string "return 1;",
+                       newline],
+                  string "}",
+                  newline,
+                  string "return 0;",
+                  newline,
+                  string "}",
+                  newline,
+                  newline,
+
+                  string "int uw_db_rollback(uw_context ctx) {",
+                  newline,
+                  string "PGconn *conn = uw_get_db(ctx);",
+                  newline,
+                  string "PGresult *res = PQexec(conn, \"ROLLBACK\");",
+                  newline,
+                  newline,
+                  string "if (res == NULL) return 1;",
+                  newline,
+                  newline,
+                  string "if (PQresultStatus(res) != PGRES_COMMAND_OK) {",
+                  box [string "PQclear(res);",
+                       newline,
+                       string "return 1;",
+                       newline],
+                  string "}",
+                  newline,
+                  string "return 0;",
+                  newline,
+                  string "}",
+                  newline,
+                  newline]
+         else
+             string "static void uw_db_prepare(uw_context ctx) { }",
+         newline,
+         newline,
+
+         string "void uw_db_init(uw_context ctx) {",
+         newline,
+         string "PGconn *conn = PQconnectdb(\"",
+         string (String.toString dbstring),
+         string "\");",
+         newline,
+         string "if (conn == NULL) uw_error(ctx, FATAL, ",
+         string "\"libpq can't allocate a connection.\");",
+         newline,
+         string "if (PQstatus(conn) != CONNECTION_OK) {",
+         newline,
+         box [string "char msg[1024];",
+              newline,
+              string "strncpy(msg, PQerrorMessage(conn), 1024);",
+              newline,
+              string "msg[1023] = 0;",
+              newline,
+              string "PQfinish(conn);",
+              newline,
+              string "uw_error(ctx, BOUNDED_RETRY, ",
+              string "\"Connection to Postgres server failed: %s\", msg);"],
+         newline,
+         string "}",
+         newline,
+         string "uw_set_db(ctx, conn);",
+         newline,
+         string "uw_db_validate(ctx);",
+         newline,
+         string "uw_db_prepare(ctx);",
+         newline,
+         string "}"]
+
+val () = addDbms {name = "postgres",
+                  header = "postgresql/libpq-fe.h",
+                  link = "-lpq",
+                  global_init = box [string "void uw_client_init() { }",
+                                     newline],
+                  init = init}
+val () = setDbms "postgres"
+
+end