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Overview
Comment: | Incomplete implementation of the COMPLETION table-valued function. So far it only works for SQL keywords. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
caefbc723b5f67afc5ef10b92b20400c |
User & Date: | drh 2017-07-11 00:09:44.330 |
Context
2017-07-11
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01:38 | The COMPLETION virtual table now looks at the names of databases, tables, and columns in addition to SQL keywords. (check-in: 1cc97711fa user: drh tags: trunk) | |
00:09 | Incomplete implementation of the COMPLETION table-valued function. So far it only works for SQL keywords. (check-in: caefbc723b user: drh tags: trunk) | |
2017-07-10
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21:32 | Fix harmless compiler warnings in lsmtest. (check-in: bd8a1fb9b3 user: mistachkin tags: trunk) | |
Changes
Added ext/misc/completion.c.
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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 an eponymous virtual table that returns suggested ** completions for a partial SQL input. ** */ #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_COMPLETIONVTAB) #if !defined(SQLITEINT_H) #include "sqlite3ext.h" #endif SQLITE_EXTENSION_INIT1 #include <assert.h> #include <string.h> #include <ctype.h> #ifndef SQLITE_OMIT_VIRTUALTABLE /* completion_vtab is a subclass of sqlite3_vtab which will ** serve as the underlying representation of a completion virtual table */ typedef struct completion_vtab completion_vtab; struct completion_vtab { sqlite3_vtab base; /* Base class - must be first */ sqlite3 *db; /* Database connection for this completion vtab */ }; /* completion_cursor is a subclass of sqlite3_vtab_cursor which will ** serve as the underlying representation of a cursor that scans ** over rows of the result */ typedef struct completion_cursor completion_cursor; struct completion_cursor { sqlite3_vtab_cursor base; /* Base class - must be first */ sqlite3 *db; /* Database connection for this cursor */ int nPrefix, nLine; /* Number of bytes in zPrefix and zLine */ char *zPrefix; /* The prefix for the word we want to complete */ char *zLine; /* The whole that we want to complete */ const char *zCurrentRow; /* Current output row */ sqlite3_stmt *pStmt; /* Current statement */ sqlite3_int64 iRowid; /* The rowid */ int ePhase; /* Current phase */ int j; /* inter-phase counter */ }; /* Values for ePhase: */ #define COMPLETION_FIRST_PHASE 0 #define COMPLETION_KEYWORDS 1 #define COMPLETION_PRAGMAS 2 #define COMPLETION_FUNCTIONS 3 #define COMPLETION_COLLATIONS 4 #define COMPLETION_INDEXES 5 #define COMPLETION_TRIGGERS 6 #define COMPLETION_DATABASES 7 #define COMPLETION_TABLES 8 #define COMPLETION_MODULES 9 #define COMPLETION_LAST_PHASE 10 /* ** The completionConnect() method is invoked to create a new ** completion_vtab that describes the completion virtual table. ** ** Think of this routine as the constructor for completion_vtab objects. ** ** All this routine needs to do is: ** ** (1) Allocate the completion_vtab object and initialize all fields. ** ** (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the ** result set of queries against completion will look like. */ static int completionConnect( sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVtab, char **pzErr ){ completion_vtab *pNew; int rc; /* Column numbers */ #define COMPLETION_COLUMN_CANDIDATE 0 /* Suggested completion of the input */ #define COMPLETION_COLUMN_PREFIX 1 /* Prefix of the word to be completed */ #define COMPLETION_COLUMN_WHOLELINE 2 /* Entire line seen so far */ rc = sqlite3_declare_vtab(db, "CREATE TABLE x(" " candidate TEXT," " prefix TEXT HIDDEN," " wholeline TEXT HIDDEN" ")"); if( rc==SQLITE_OK ){ pNew = sqlite3_malloc( sizeof(*pNew) ); *ppVtab = (sqlite3_vtab*)pNew; if( pNew==0 ) return SQLITE_NOMEM; memset(pNew, 0, sizeof(*pNew)); pNew->db = db; } return rc; } /* ** This method is the destructor for completion_cursor objects. */ static int completionDisconnect(sqlite3_vtab *pVtab){ sqlite3_free(pVtab); return SQLITE_OK; } /* ** Constructor for a new completion_cursor object. */ static int completionOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){ completion_cursor *pCur; pCur = sqlite3_malloc( sizeof(*pCur) ); if( pCur==0 ) return SQLITE_NOMEM; memset(pCur, 0, sizeof(*pCur)); pCur->db = ((completion_vtab*)p)->db; *ppCursor = &pCur->base; return SQLITE_OK; } /* ** Reset the completion_cursor. */ static void completionCursorReset(completion_cursor *pCur){ sqlite3_free(pCur->zPrefix); pCur->zPrefix = 0; pCur->nPrefix = 0; sqlite3_free(pCur->zLine); pCur->zLine = 0; pCur->nLine = 0; sqlite3_finalize(pCur->pStmt); pCur->pStmt = 0; } /* ** Destructor for a completion_cursor. */ static int completionClose(sqlite3_vtab_cursor *cur){ completionCursorReset((completion_cursor*)cur); sqlite3_free(cur); return SQLITE_OK; } /* ** All SQL keywords understood by SQLite */ static const char *completionKwrds[] = { "ABORT", "ACTION", "ADD", "AFTER", "ALL", "ALTER", "ANALYZE", "AND", "AS", "ASC", "ATTACH", "AUTOINCREMENT", "BEFORE", "BEGIN", "BETWEEN", "BY", "CASCADE", "CASE", "CAST", "CHECK", "COLLATE", "COLUMN", "COMMIT", "CONFLICT", "CONSTRAINT", "CREATE", "CROSS", "CURRENT_DATE", "CURRENT_TIME", "CURRENT_TIMESTAMP", "DATABASE", "DEFAULT", "DEFERRABLE", "DEFERRED", "DELETE", "DESC", "DETACH", "DISTINCT", "DROP", "EACH", "ELSE", "END", "ESCAPE", "EXCEPT", "EXCLUSIVE", "EXISTS", "EXPLAIN", "FAIL", "FOR", "FOREIGN", "FROM", "FULL", "GLOB", "GROUP", "HAVING", "IF", "IGNORE", "IMMEDIATE", "IN", "INDEX", "INDEXED", "INITIALLY", "INNER", "INSERT", "INSTEAD", "INTERSECT", "INTO", "IS", "ISNULL", "JOIN", "KEY", "LEFT", "LIKE", "LIMIT", "MATCH", "NATURAL", "NO", "NOT", "NOTNULL", "NULL", "OF", "OFFSET", "ON", "OR", "ORDER", "OUTER", "PLAN", "PRAGMA", "PRIMARY", "QUERY", "RAISE", "RECURSIVE", "REFERENCES", "REGEXP", "REINDEX", "RELEASE", "RENAME", "REPLACE", "RESTRICT", "RIGHT", "ROLLBACK", "ROW", "SAVEPOINT", "SELECT", "SET", "TABLE", "TEMP", "TEMPORARY", "THEN", "TO", "TRANSACTION", "TRIGGER", "UNION", "UNIQUE", "UPDATE", "USING", "VACUUM", "VALUES", "VIEW", "VIRTUAL", "WHEN", "WHERE", "WITH", "WITHOUT", }; /* ** Advance a completion_cursor to its next row of output. */ static int completionNext(sqlite3_vtab_cursor *cur){ completion_cursor *pCur = (completion_cursor*)cur; pCur->iRowid++; if( pCur->ePhase==COMPLETION_FIRST_PHASE ){ pCur->ePhase = COMPLETION_KEYWORDS; pCur->j = -1; } if( pCur->ePhase==COMPLETION_KEYWORDS ){ while(1){ const char *z; pCur->j++; if( pCur->j >= sizeof(completionKwrds)/sizeof(completionKwrds[0]) ){ pCur->ePhase = COMPLETION_LAST_PHASE; break; } z = completionKwrds[pCur->j]; if( pCur->nPrefix==0 || sqlite3_strnicmp(pCur->zPrefix, z, pCur->nPrefix)==0 ){ pCur->zCurrentRow = z; break; } } } return SQLITE_OK; } /* ** Return values of columns for the row at which the completion_cursor ** is currently pointing. */ static int completionColumn( sqlite3_vtab_cursor *cur, /* The cursor */ sqlite3_context *ctx, /* First argument to sqlite3_result_...() */ int i /* Which column to return */ ){ completion_cursor *pCur = (completion_cursor*)cur; switch( i ){ case COMPLETION_COLUMN_CANDIDATE: { sqlite3_result_text(ctx, pCur->zCurrentRow, -1, SQLITE_TRANSIENT); break; } case COMPLETION_COLUMN_PREFIX: { sqlite3_result_text(ctx, pCur->zPrefix, -1, SQLITE_TRANSIENT); break; } case COMPLETION_COLUMN_WHOLELINE: { sqlite3_result_text(ctx, pCur->zLine, -1, SQLITE_TRANSIENT); break; } } return SQLITE_OK; } /* ** Return the rowid for the current row. In this implementation, the ** rowid is the same as the output value. */ static int completionRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ completion_cursor *pCur = (completion_cursor*)cur; *pRowid = pCur->iRowid; return SQLITE_OK; } /* ** Return TRUE if the cursor has been moved off of the last ** row of output. */ static int completionEof(sqlite3_vtab_cursor *cur){ completion_cursor *pCur = (completion_cursor*)cur; return pCur->ePhase >= COMPLETION_LAST_PHASE; } /* ** This method is called to "rewind" the completion_cursor object back ** to the first row of output. This method is always called at least ** once prior to any call to completionColumn() or completionRowid() or ** completionEof(). */ static int completionFilter( sqlite3_vtab_cursor *pVtabCursor, int idxNum, const char *idxStr, int argc, sqlite3_value **argv ){ completion_cursor *pCur = (completion_cursor *)pVtabCursor; int iArg = 0; completionCursorReset(pCur); if( idxNum & 1 ){ pCur->nPrefix = sqlite3_value_bytes(argv[iArg]); if( pCur->nPrefix>0 ){ pCur->zPrefix = sqlite3_mprintf("%s", sqlite3_value_text(argv[iArg])); if( pCur->zPrefix==0 ) return SQLITE_NOMEM; } iArg++; } if( idxNum & 2 ){ pCur->nLine = sqlite3_value_bytes(argv[iArg]); if( pCur->nLine>0 ){ pCur->zLine = sqlite3_mprintf("%s", sqlite3_value_text(argv[iArg])); if( pCur->zLine==0 ) return SQLITE_NOMEM; } iArg++; } if( pCur->zLine!=0 && pCur->zPrefix==0 ){ int i = pCur->nLine; while( i>0 && (isalnum(pCur->zLine[i-1]) || pCur->zLine[i-1]=='_') ){ i--; } pCur->nPrefix = pCur->nLine - i; if( pCur->nPrefix>0 ){ pCur->zPrefix = sqlite3_mprintf("%.*s", pCur->nPrefix, pCur->zLine + i); if( pCur->zPrefix==0 ) return SQLITE_NOMEM; } } pCur->iRowid = 0; pCur->ePhase = COMPLETION_FIRST_PHASE; return completionNext(pVtabCursor); } /* ** SQLite will invoke this method one or more times while planning a query ** that uses the completion virtual table. This routine needs to create ** a query plan for each invocation and compute an estimated cost for that ** plan. ** ** There are two hidden parameters that act as arguments to the table-valued ** function: "prefix" and "wholeline". Bit 0 of idxNum is set if "prefix" ** is available and bit 1 is set if "wholeline" is available. */ static int completionBestIndex( sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo ){ int i; /* Loop over constraints */ int idxNum = 0; /* The query plan bitmask */ int prefixIdx = -1; /* Index of the start= constraint, or -1 if none */ int wholelineIdx = -1; /* Index of the stop= constraint, or -1 if none */ int nArg = 0; /* Number of arguments that completeFilter() expects */ const struct sqlite3_index_constraint *pConstraint; pConstraint = pIdxInfo->aConstraint; for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){ if( pConstraint->usable==0 ) continue; if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue; switch( pConstraint->iColumn ){ case COMPLETION_COLUMN_PREFIX: prefixIdx = i; idxNum |= 1; break; case COMPLETION_COLUMN_WHOLELINE: wholelineIdx = i; idxNum |= 2; break; } } if( prefixIdx>=0 ){ pIdxInfo->aConstraintUsage[prefixIdx].argvIndex = ++nArg; pIdxInfo->aConstraintUsage[prefixIdx].omit = 1; } if( wholelineIdx>=0 ){ pIdxInfo->aConstraintUsage[wholelineIdx].argvIndex = ++nArg; pIdxInfo->aConstraintUsage[wholelineIdx].omit = 1; } pIdxInfo->idxNum = idxNum; pIdxInfo->estimatedCost = (double)5000 - 1000*nArg; pIdxInfo->estimatedRows = 500 - 100*nArg; return SQLITE_OK; } /* ** This following structure defines all the methods for the ** completion virtual table. */ static sqlite3_module completionModule = { 0, /* iVersion */ 0, /* xCreate */ completionConnect, /* xConnect */ completionBestIndex, /* xBestIndex */ completionDisconnect, /* xDisconnect */ 0, /* xDestroy */ completionOpen, /* xOpen - open a cursor */ completionClose, /* xClose - close a cursor */ completionFilter, /* xFilter - configure scan constraints */ completionNext, /* xNext - advance a cursor */ completionEof, /* xEof - check for end of scan */ completionColumn, /* xColumn - read data */ completionRowid, /* xRowid - read data */ 0, /* xUpdate */ 0, /* xBegin */ 0, /* xSync */ 0, /* xCommit */ 0, /* xRollback */ 0, /* xFindMethod */ 0, /* xRename */ }; #endif /* SQLITE_OMIT_VIRTUALTABLE */ int sqlite3CompletionVtabInit(sqlite3 *db){ int rc = SQLITE_OK; #ifndef SQLITE_OMIT_VIRTUALTABLE rc = sqlite3_create_module(db, "completion", &completionModule, 0); #endif return rc; } #ifndef SQLITE_CORE #ifdef _WIN32 __declspec(dllexport) #endif int sqlite3_completion_init( sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi ){ int rc = SQLITE_OK; SQLITE_EXTENSION_INIT2(pApi); #ifndef SQLITE_OMIT_VIRTUALTABLE rc = sqlite3CompletionVtabInit(db); #endif return rc; } #endif /* SQLITE_CORE */ #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_COMPLETIONVTAB) */ |