ext/misc/urifuncs.c

   1 /*
   2 ** 2020-01-11
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 ******************************************************************************
  12 **
  13 ** This SQLite extension implements various SQL functions used to access
  14 ** the following SQLite C-language APIs:
  15 **
  16 **         sqlite3_uri_parameter()
  17 **         sqlite3_uri_boolean()
  18 **         sqlite3_uri_int64()
  19 **         sqlite3_uri_key()
  20 **         sqlite3_filename_database()
  21 **         sqlite3_filename_journal()
  22 **         sqlite3_filename_wal()
  23 **         sqlite3_db_filename()
  24 **
  25 ** These SQL functions are for testing and demonstration purposes only.
  26 **
  27 **
  28 */
  29 #include "sqlite3ext.h"
  30 SQLITE_EXTENSION_INIT1
  31 #include <assert.h>
  32 #include <string.h>
  33
  34 /*
  35 ** SQL function:    sqlite3_db_filename(SCHEMA)
  36 **
  37 ** Return the filename corresponding to SCHEMA.
  38 */
  39 static void func_db_filename(
  40   sqlite3_context *context,
  41   int argc,
  42   sqlite3_value **argv
  43 ){
  44   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
  45   sqlite3 *db = sqlite3_context_db_handle(context);
  46   const char *zFile = sqlite3_db_filename(db, zSchema);
  47   sqlite3_result_text(context, zFile, -1, SQLITE_TRANSIENT);
  48 }
  49
  50 /*
  51 ** SQL function:    sqlite3_uri_parameter(SCHEMA,NAME)
  52 **
  53 ** Return the value of the NAME query parameter to the database for SCHEMA
  54 */
  55 static void func_uri_parameter(
  56   sqlite3_context *context,
  57   int argc,
  58   sqlite3_value **argv
  59 ){
  60   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
  61   sqlite3 *db = sqlite3_context_db_handle(context);
  62   const char *zName = (const char*)sqlite3_value_text(argv[1]);
  63   const char *zFile = sqlite3_db_filename(db, zSchema);
  64   const char *zRes = sqlite3_uri_parameter(zFile, zName);
  65   sqlite3_result_text(context, zRes, -1, SQLITE_TRANSIENT);
  66 }
  67
  68 /*
  69 ** SQL function:    sqlite3_uri_boolean(SCHEMA,NAME,DEFAULT)
  70 **
  71 ** Return the boolean value of the NAME query parameter to
  72 ** the database for SCHEMA
  73 */
  74 static void func_uri_boolean(
  75   sqlite3_context *context,
  76   int argc,
  77   sqlite3_value **argv
  78 ){
  79   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
  80   sqlite3 *db = sqlite3_context_db_handle(context);
  81   const char *zName = (const char*)sqlite3_value_text(argv[1]);
  82   const char *zFile = sqlite3_db_filename(db, zSchema);
  83   int iDflt = sqlite3_value_int(argv[2]);
  84   int iRes = sqlite3_uri_boolean(zFile, zName, iDflt);
  85   sqlite3_result_int(context, iRes);
  86 }
  87
  88 /*
  89 ** SQL function:    sqlite3_uri_key(SCHEMA,N)
  90 **
  91 ** Return the name of the Nth query parameter
  92 */
  93 static void func_uri_key(
  94   sqlite3_context *context,
  95   int argc,
  96   sqlite3_value **argv
  97 ){
  98   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
  99   sqlite3 *db = sqlite3_context_db_handle(context);
 100   int N = sqlite3_value_int(argv[1]);
 101   const char *zFile = sqlite3_db_filename(db, zSchema);
 102   const char *zRes = sqlite3_uri_key(zFile, N);
 103   sqlite3_result_text(context, zRes, -1, SQLITE_TRANSIENT);
 104 }
 105
 106 /*
 107 ** SQL function:    sqlite3_uri_int64(SCHEMA,NAME,DEFAULT)
 108 **
 109 ** Return the int64 value of the NAME query parameter to
 110 ** the database for SCHEMA
 111 */
 112 static void func_uri_int64(
 113   sqlite3_context *context,
 114   int argc,
 115   sqlite3_value **argv
 116 ){
 117   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
 118   sqlite3 *db = sqlite3_context_db_handle(context);
 119   const char *zName = (const char*)sqlite3_value_text(argv[1]);
 120   const char *zFile = sqlite3_db_filename(db, zSchema);
 121   sqlite3_int64 iDflt = sqlite3_value_int64(argv[2]);
 122   sqlite3_int64 iRes = sqlite3_uri_int64(zFile, zName, iDflt);
 123   sqlite3_result_int64(context, iRes);
 124 }
 125
 126 /*
 127 ** SQL function:    sqlite3_filename_database(SCHEMA)
 128 **
 129 ** Return the database filename for SCHEMA
 130 */
 131 static void func_filename_database(
 132   sqlite3_context *context,
 133   int argc,
 134   sqlite3_value **argv
 135 ){
 136   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
 137   sqlite3 *db = sqlite3_context_db_handle(context);
 138   const char *zFile = sqlite3_db_filename(db, zSchema);
 139   const char *zRes = zFile ? sqlite3_filename_database(zFile) : 0;
 140   sqlite3_result_text(context, zRes, -1, SQLITE_TRANSIENT);
 141 }
 142
 143 /*
 144 ** SQL function:    sqlite3_filename_journal(SCHEMA)
 145 **
 146 ** Return the rollback journal filename for SCHEMA
 147 */
 148 static void func_filename_journal(
 149   sqlite3_context *context,
 150   int argc,
 151   sqlite3_value **argv
 152 ){
 153   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
 154   sqlite3 *db = sqlite3_context_db_handle(context);
 155   const char *zFile = sqlite3_db_filename(db, zSchema);
 156   const char *zRes = zFile ? sqlite3_filename_journal(zFile) : 0;
 157   sqlite3_result_text(context, zRes, -1, SQLITE_TRANSIENT);
 158 }
 159
 160 /*
 161 ** SQL function:    sqlite3_filename_wal(SCHEMA)
 162 **
 163 ** Return the WAL filename for SCHEMA
 164 */
 165 static void func_filename_wal(
 166   sqlite3_context *context,
 167   int argc,
 168   sqlite3_value **argv
 169 ){
 170   const char *zSchema = (const char*)sqlite3_value_text(argv[0]);
 171   sqlite3 *db = sqlite3_context_db_handle(context);
 172   const char *zFile = sqlite3_db_filename(db, zSchema);
 173   const char *zRes = zFile ? sqlite3_filename_wal(zFile) : 0;
 174   sqlite3_result_text(context, zRes, -1, SQLITE_TRANSIENT);
 175 }
 176
 177 #ifdef _WIN32
 178 __declspec(dllexport)
 179 #endif
 180 int sqlite3_urifuncs_init(
 181   sqlite3 *db,
 182   char **pzErrMsg,
 183   const sqlite3_api_routines *pApi
 184 ){
 185   static const struct {
 186     const char *zFuncName;
 187     int nArg;
 188     void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
 189   } aFunc[] = {
 190     { "sqlite3_db_filename",       1, func_db_filename       },
 191     { "sqlite3_uri_parameter",     2, func_uri_parameter     },
 192     { "sqlite3_uri_boolean",       3, func_uri_boolean       },
 193     { "sqlite3_uri_int64",         3, func_uri_int64         },
 194     { "sqlite3_uri_key",           2, func_uri_key           },
 195     { "sqlite3_filename_database", 1, func_filename_database },
 196     { "sqlite3_filename_journal",  1, func_filename_journal  },
 197     { "sqlite3_filename_wal",      1, func_filename_wal      },
 198   };
 199   int rc = SQLITE_OK;
 200   int i;
 201   SQLITE_EXTENSION_INIT2(pApi);
 202   (void)pzErrMsg;  /* Unused parameter */
 203   for(i=0; rc==SQLITE_OK && i<sizeof(aFunc)/sizeof(aFunc[0]); i++){
 204     rc = sqlite3_create_function(db, aFunc[i].zFuncName, aFunc[i].nArg,
 205                      SQLITE_UTF8, 0,
 206                      aFunc[i].xFunc, 0, 0);
 207   }
 208   return rc;
 209 }