/*
2022-05-22
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 is intended to be appended to the emcc-generated
sqlite3.js via emcc:
emcc ... -sMODULARIZE -sEXPORT_NAME=initSqlite3Module --post-js=THIS_FILE
It is loaded by importing the emcc-generated sqlite3.js, then:
initSqlite3Module({module object}).then(
function(theModule){
theModule.sqlite3 == an object containing this file's
deliverables:
{
api: bindings for much of the core sqlite3 APIs,
SQLite3: high-level OO API wrapper
}
});
It is up to the caller to provide a module object compatible with
emcc, but it can be a plain empty object. The object passed to
initSqlite3Module() will get populated by the emscripten-generated
bits and, in part, by the code from this file. Specifically, this file
installs the `theModule.sqlite3` part shown above.
The resulting sqlite3.api object wraps the standard sqlite3 C API in
a way as close to its native form as JS allows for. The
sqlite3.SQLite3 object provides a higher-level wrapper more
appropriate for general client-side use in JS.
Because using certain parts of the low-level API properly requires
some degree of WASM-related magic, it is not recommended that that
API be used as-is in client-level code. Rather, client code should
use the higher-level OO API or write a custom wrapper on top of the
lower-level API. In short, most of the C-style API is used in an
intuitive manner from JS but any C-style APIs which take
pointers-to-pointer arguments require WASM-specific interfaces
installed by emcscripten-generated code. Those which take or return
only integers, doubles, strings, or "plain" pointers to db or
statement objects can be used in "as normal," noting that "pointers"
in wasm are simply 32-bit integers.
# Goals and Non-goals of this API
Goals:
- Except where noted in the non-goals, provide a more-or-less
complete wrapper to the sqlite3 C API, insofar as WASM feature
parity with C allows for. In fact, provide at least 3...
- (1) The aforementioned C-style API. (2) An OO-style API on
top of that, designed to run in the same thread (main window or
Web Worker) as the C API. (3) A less-capable wrapper which can
work across the main window/worker boundary, where the sqlite3 API
is one of those and this wrapper is in the other. That
constellation places some considerable limitations on how the API
can be interacted with, but keeping the DB operations out of the
UI thread is generally desirable.
- Insofar as possible, support client-side storage using JS
filesystem APIs. As of this writing, such things are still very
much TODO.
Non-goals:
- As WASM is a web-centric technology and UTF-8 is the King of
Encodings in that realm, there are no current plans to support the
UTF16-related APIs. They would add a complication to the bindings
for no appreciable benefit.
- Supporting old or niche-market platforms. WASM is built for a
modern web and requires modern platforms.
*/
if(!Module.postRun) Module.postRun = [];
/* ^^^^ the name Module is, in this setup, scope-local in the generated
file sqlite3.js, with which this file gets combined at build-time. */
Module.postRun.push(function(namespace/*the module object, the target for
installed features*/){
'use strict';
/* For reference: sql.js does essentially everything we want and
it solves much of the wasm-related voodoo, but we'll need a
different structure because we want the db connection to run in
a worker thread and feed data back into the main
thread. Regardless of those differences, it makes a great point
of reference:
https://github.com/sql-js/sql.js
Some of the specific design goals here:
- Bind a low-level sqlite3 API which is close to the native one
in terms of usage.
- Create a higher-level one, more akin to sql.js and
node.js-style implementations. This one would speak directly
to the low-level API. This API could be used by clients who
import the low-level API directly into their main thread
(which we don't want to recommend but also don't want to
outright forbid).
- Create a second higher-level one which speaks to the
low-level API via worker messages. This one would be intended
for use in the main thread, talking to the low-level UI via
worker messages. Because workers have only a single message
channel, some acrobatics will be needed here to feed async
work results back into client-side callbacks (as those
callbacks cannot simply be passed to the worker). Exactly
what those acrobatics should look like is not yet entirely
clear and much experimentation is pending.
*/
const SQM = namespace/*the sqlite module object */;
/**
Set up the main sqlite3 binding API here, mimicking the C API as
closely as we can.
Attribution: though not a direct copy/paste, much of what
follows is strongly influenced by the sql.js implementation.
*/
const api = {
/* It is important that the following integer values match
those from the C code. Ideally we could fetch them from the
C API, e.g., in the form of a JSON object, but getting that
JSON string constructed within our current confines is
currently not worth the effort.
Reminder to self: we could probably do so by adding the
proverbial level of indirection, calling in to C to get it,
and having that C func call an
emscripten-installed/JS-implemented library function which
builds the result object:
const obj = {};
sqlite3__get_enum(function(key,val){
obj[key] = val;
});
but whether or not we can pass a function that way, via a
(void*) is as yet unknown.
*/
/* Minimum subset of sqlite result codes we'll need. */
SQLITE_OK: 0,
SQLITE_ROW: 100,
SQLITE_DONE: 101,
/* sqlite data types */
SQLITE_INTEGER: 1,
SQLITE_FLOAT: 2,
SQLITE_TEXT: 3,
SQLITE_BLOB: 4,
SQLITE_NULL: 5,
/* create_function() flags */
SQLITE_DETERMINISTIC: 0x000000800,
SQLITE_DIRECTONLY: 0x000080000,
SQLITE_INNOCUOUS: 0x000200000,
/* sqlite encodings, used for creating UDFs, noting that we
will only support UTF8. */
SQLITE_UTF8: 1
};
const cwrap = SQM.cwrap;
[/* C-side functions to bind. Each entry is an array with 3 or 4
elements:
["c-side name",
"result type" (cwrap() syntax),
[arg types in cwrap() syntax]
]
If it has 4 elements, the first one is an alternate name to
use for the JS-side binding. That's required when overloading
a binding for two different uses.
*/
["sqlite3_bind_blob","number",["number", "number", "number", "number", "number"]],
["sqlite3_bind_double","number",["number", "number", "number"]],
["sqlite3_bind_int","number",["number", "number", "number"]],
/*Noting that JS/wasm combo does not currently support 64-bit integers:
["sqlite3_bind_int64","number",["number", "number", "number"]],*/
["sqlite3_bind_null","void",["number"]],
["sqlite3_bind_parameter_count", "number", ["number"]],
["sqlite3_bind_parameter_index","number",["number", "string"]],
["sqlite3_bind_text","number",["number", "number", "number", "number", "number"]],
["sqlite3_changes", "number", ["number"]],
["sqlite3_clear_bindings","number",["number"]],
["sqlite3_close_v2", "number", ["number"]],
["sqlite3_column_blob","number", ["number", "number"]],
["sqlite3_column_bytes","number",["number", "number"]],
["sqlite3_column_count", "number", ["number"]],
["sqlite3_column_count","number",["number"]],
["sqlite3_column_double","number",["number", "number"]],
["sqlite3_column_int","number",["number", "number"]],
/*Noting that JS/wasm combo does not currently support 64-bit integers:
["sqlite3_column_int64","number",["number", "number"]],*/
["sqlite3_column_name","string",["number", "number"]],
["sqlite3_column_text","string",["number", "number"]],
["sqlite3_column_type","number",["number", "number"]],
["sqlite3_compileoption_get", "string", ["number"]],
["sqlite3_compileoption_used", "number", ["string"]],
["sqlite3_create_function_v2", "number",
["number", "string", "number", "number","number",
"number", "number", "number", "number"]],
["sqlite3_data_count", "number", ["number"]],
["sqlite3_db_filename", "string", ["number", "string"]],
["sqlite3_errmsg", "string", ["number"]],
["sqlite3_exec", "number", ["number", "string", "number", "number", "number"]],
["sqlite3_finalize", "number", ["number"]],
["sqlite3_interrupt", "void", ["number"]],
["sqlite3_libversion", "string", []],
["sqlite3_open", "number", ["string", "number"]],
//["sqlite3_open_v2", "number", ["string", "number", "number", "string"]],
//^^^^ TODO: add the flags needed for the 3rd arg
["sqlite3_prepare_v2", "number", ["number", "string", "number", "number", "number"]],
["sqlite3_prepare_v2_sqlptr", "sqlite3_prepare_v2",
/* Impl which requires that the 2nd argument be a pointer to
the SQL string, instead of being converted to a
string. This is used for cases where we require a non-NULL
value for the final argument (exec()'ing multiple
statements from one input string). */
"number", ["number", "number", "number", "number", "number"]],
["sqlite3_reset", "number", ["number"]],
["sqlite3_result_blob",null,["number", "number", "number", "number"]],
["sqlite3_result_double",null,["number", "number"]],
["sqlite3_result_error",null,["number", "string", "number"]],
["sqlite3_result_int",null,["number", "number"]],
["sqlite3_result_null",null,["number"]],
["sqlite3_result_text",null,["number", "string", "number", "number"]],
["sqlite3_sourceid", "string", []],
["sqlite3_sql", "string", ["number"]],
["sqlite3_step", "number", ["number"]],
["sqlite3_value_blob", "number", ["number"]],
["sqlite3_value_bytes","number",["number"]],
["sqlite3_value_double","number",["number"]],
["sqlite3_value_text", "string", ["number"]],
["sqlite3_value_type", "number", ["number"]]
//["sqlite3_normalized_sql", "string", ["number"]]
].forEach(function(a){
const k = (4==a.length) ? a.shift() : a[0];
api[k] = cwrap.apply(this, a);
});
/* What follows is colloquially known as "OO API #1". It is a
binding of the sqlite3 API which is designed to be run within
the same thread (main or worker) as the one in which the
sqlite3 WASM binding was initialized. This wrapper cannot use
the sqlite3 binding if, e.g., the wrapper is in the main thread
and the sqlite3 API is in a worker. */
/** Memory for use in some pointer-to-pointer-passing routines. */
const pPtrArg = stackAlloc(4);
/** Throws a new error, concatenating all args with a space between
each. */
const toss = function(){
throw new Error(Array.prototype.join.call(arguments, ' '));
};
/**
The DB class wraps a sqlite3 db handle.
It accepts the following argument signatures:
- ()
- (undefined) (same effect as ())
- (filename[,buffer])
- (buffer)
Where a buffer indicates a Uint8Array holding an sqlite3 db
image.
If the filename is provided, only the last component of the
path is used - any path prefix is stripped and certain
"special" characters are replaced with `_`. If no name is
provided, a random name is generated. The resulting filename is
the one used for accessing the db file within root directory of
the emscripten-supplied virtual filesystem, and is set (with no
path part) as the DB object's `filename` property.
Note that the special sqlite3 db names ":memory:" and ""
(temporary db) have no special meanings here. We can apparently
only export images of DBs which are stored in the
pseudo-filesystem provided by the JS APIs. Since exporting and
importing images is an important usability feature for this
class, ":memory:" DBs are not supported (until/unless we can
find a way to export those as well). The naming semantics will
certainly evolve as this API does.
*/
const DB = function(arg){
let buffer, fn;
if(arg instanceof Uint8Array){
buffer = arg;
arg = undefined;
}else if(arguments.length){ /*(filename[,buffer])*/
if('string'===typeof arg){
const p = arg.split('/').pop().replace(':','_');
if(p) fn = p;
if(arguments.length>1){
buffer = arguments[1];
}
}else if(undefined!==arg){
toss("Invalid arguments to DB constructor.",
"Expecting (), (undefined), (name,buffer),",
"or (buffer), where buffer an sqlite3 db ",
"as a Uint8Array.");
}
}
if(!fn){
fn = "db-"+((Math.random() * 10000000) | 0)+
"-"+((Math.random() * 10000000) | 0)+".sqlite3";
}
if(buffer){
if(!(buffer instanceof Uint8Array)){
toss("Expecting Uint8Array image of db contents.");
}
FS.createDataFile("/", fn, buffer, true, true);
}
setValue(pPtrArg, 0, "i32");
this.checkRc(api.sqlite3_open(fn, pPtrArg));
this._pDb = getValue(pPtrArg, "i32");
this.filename = fn;
this._statements = {/*map of open Stmt _pointers_ to Stmt*/};
this._udfs = {/*map of UDF names to wasm function _pointers_*/};
};
/**
Internal-use enum for mapping JS types to DB-bindable types.
These do not (and need not) line up with the SQLITE_type
values. All values in this enum must be truthy and distinct
but they need not be numbers.
*/
const BindTypes = {
null: 1,
number: 2,
string: 3,
boolean: 4,
blob: 5
};
BindTypes['undefined'] == BindTypes.null;
/**
This class wraps sqlite3_stmt. Calling this constructor
directly will trigger an exception. Use DB.prepare() to create
new instances.
*/
const Stmt = function(){
if(BindTypes!==arguments[2]){
toss("Do not call the Stmt constructor directly. Use DB.prepare().");
}
this.db = arguments[0];
this._pStmt = arguments[1];
this.columnCount = api.sqlite3_column_count(this._pStmt);
this.parameterCount = api.sqlite3_bind_parameter_count(this._pStmt);
this._allocs = [/*list of alloc'd memory blocks for bind() values*/]
};
/** Throws if the given DB has been closed, else it is returned. */
const affirmDbOpen = function(db){
if(!db._pDb) toss("DB has been closed.");
return db;
};
/** Returns true if n is a 32-bit (signed) integer,
else false. */
const isInt32 = function(n){
return (n===n|0 && n<0xFFFFFFFF) ? true : undefined;
};
/**
Expects to be passed (arguments) from DB.exec() and
DB.execMulti(). Does the argument processing/validation, throws
on error, and returns a new object on success:
{ sql: the SQL, obt: optionsObj, cbArg: function}
cbArg is only set if the opt.callback is set, in which case
it's a function which expects to be passed the current Stmt
and returns the callback argument of the type indicated by
the input arguments.
*/
const parseExecArgs = function(args){
const out = {};
switch(args.length){
case 1:
if('string'===typeof args[0]){
out.sql = args[0];
out.opt = {};
}else if(args[0] && 'object'===typeof args[0]){
out.opt = args[0];
out.sql = out.opt.sql;
}
break;
case 2:
out.sql = args[0];
out.opt = args[1];
break;
default: toss("Invalid argument count for exec().");
};
if('string'!==typeof out.sql) toss("Missing SQL argument.");
if(out.opt.callback || out.opt.resultRows){
switch((undefined===out.opt.rowMode)
? 'stmt' : out.opt.rowMode) {
case 'object': out.cbArg = (stmt)=>stmt.get({}); break;
case 'array': out.cbArg = (stmt)=>stmt.get([]); break;
case 'stmt': out.cbArg = (stmt)=>stmt; break;
default: toss("Invalid rowMode:",out.opt.rowMode);
}
}
return out;
};
/** If object opts has _its own_ property named p then that
property's value is returned, else dflt is returned. */
const getOwnOption = (opts, p, dflt)=>
opts.hasOwnProperty(p) ? opts[p] : dflt;
DB.prototype = {
/**
Expects to be given an sqlite3 API result code. If it is
falsy, this function returns this object, else it throws an
exception with an error message from sqlite3_errmsg(),
using this object's db handle. Note that if it's passed a
non-error code like SQLITE_ROW or SQLITE_DONE, it will
still throw but the error string might be "Not an error."
The various non-0 non-error codes need to be checked for in
client code where they are expected.
*/
checkRc: function(sqliteResultCode){
if(!sqliteResultCode) return this;
toss("sqlite result code",sqliteResultCode+":",
api.sqlite3_errmsg(this._pDb) || "Unknown db error.");
},
/**
Finalizes all open statements and closes this database
connection. This is a no-op if the db has already been
closed. If the db is open and alsoUnlink is truthy then the
this.filename entry in the pseudo-filesystem will also be
removed (and any error in that attempt is silently
ignored).
*/
close: function(alsoUnlink){
if(this._pDb){
let s;
const that = this;
Object.keys(this._statements).forEach(function(k,s){
delete that._statements[k];
if(s && s._pStmt) s.finalize();
});
Object.values(this._udfs).forEach(SQM.removeFunction);
delete this._udfs;
delete this._statements;
api.sqlite3_close_v2(this._pDb);
delete this._pDb;
if(this.filename){
if(alsoUnlink){
try{SQM.FS.unlink('/'+this.filename);}
catch(e){/*ignored*/}
}
delete this.filename;
}
}
},
/**
Similar to this.filename but will return NULL for
special names like ":memory:". Not of much use until
we have filesystem support. Throws if the DB has
been closed. If passed an argument it then it will return
the filename of the ATTACHEd db with that name, else it assumes
a name of `main`.
*/
fileName: function(dbName){
return api.sqlite3_db_filename(affirmDbOpen(this)._pDb, dbName||"main");
},
/**
Compiles the given SQL and returns a prepared Stmt. This is
the only way to create new Stmt objects. Throws on error.
*/
prepare: function(sql){
affirmDbOpen(this);
setValue(pPtrArg,0,"i32");
this.checkRc(api.sqlite3_prepare_v2(this._pDb, sql, -1, pPtrArg, null));
const pStmt = getValue(pPtrArg, "i32");
if(!pStmt) toss("Empty SQL is not permitted.");
const stmt = new Stmt(this, pStmt, BindTypes);
this._statements[pStmt] = stmt;
return stmt;
},
/**
This function works like execMulti(), and takes most of the
same arguments, but is more efficient (performs much less
work) when the input SQL is only a single statement. If
passed a multi-statement SQL, it only processes the first
one.
This function supports the following additional options not
supported by execMulti():
- .multi: if true, this function acts as a proxy for
execMulti() and behaves identically to that function.
- .resultRows: if this is an array, each row of the result
set (if any) is appended to it in the format specified
for the `rowMode` property, with the exception that the
only legal values for `rowMode` in this case are 'array'
or 'object', neither of which is the default. It is legal
to use both `resultRows` and `callback`, but `resultRows`
is likely much simpler to use for small data sets and can
be used over a WebWorker-style message interface.
- .columnNames: if this is an array and the query has
result columns, the array is passed to
Stmt.getColumnNames() to append the column names to it
(regardless of whether the query produces any result
rows). If the query has no result columns, this value is
unchanged.
The following options to execMulti() are _not_ supported by
this method (they are simply ignored):
- .saveSql
*/
exec: function(/*(sql [,optionsObj]) or (optionsObj)*/){
affirmDbOpen(this);
const arg = parseExecArgs(arguments);
if(!arg.sql) return this;
else if(arg.opt.multi){
return this.execMulti(arg, undefined, BindTypes);
}
const opt = arg.opt;
let stmt, rowTarget;
try {
if(Array.isArray(opt.resultRows)){
if(opt.rowMode!=='array' && opt.rowMode!=='object'){
toss("Invalid rowMode for resultRows array: must",
"be one of 'array' or 'object'.");
}
rowTarget = opt.resultRows;
}
stmt = this.prepare(arg.sql);
if(stmt.columnCount && Array.isArray(opt.columnNames)){
stmt.getColumnNames(opt.columnNames);
}
if(opt.bind) stmt.bind(opt.bind);
if(opt.callback || rowTarget){
while(stmt.step()){
const row = arg.cbArg(stmt);
if(rowTarget) rowTarget.push(row);
if(opt.callback){
stmt._isLocked = true;
opt.callback(row, stmt);
stmt._isLocked = false;
}
}
}else{
stmt.step();
}
}finally{
if(stmt){
delete stmt._isLocked;
stmt.finalize();
}
}
return this;
}/*exec()*/,
/**
Executes one or more SQL statements in the form of a single
string. Its arguments must be either (sql,optionsObject) or
(optionsObject). In the latter case, optionsObject.sql
must contain the SQL to execute. Returns this
object. Throws on error.
If no SQL is provided, or a non-string is provided, an
exception is triggered. Empty SQL, on the other hand, is
simply a no-op.
The optional options object may contain any of the following
properties:
- .sql = the SQL to run (unless it's provided as the first
argument).
- .bind = a single value valid as an argument for
Stmt.bind(). This is ONLY applied to the FIRST non-empty
statement in the SQL which has any bindable
parameters. (Empty statements are skipped entirely.)
- .callback = a function which gets called for each row of
the FIRST statement in the SQL (if it has any result
rows). The second argument passed to the callback is
always the current Stmt object (so that the caller
may collect column names, or similar). The first
argument passed to the callback defaults to the current
Stmt object but may be changed with ...
- .rowMode = a string describing what type of argument
should be passed as the first argument to the callback. A
value of 'object' causes the results of `stmt.get({})` to
be passed to the object. A value of 'array' causes the
results of `stmt.get([])` to be passed to the callback.
A value of 'stmt' is equivalent to the default, passing
the current Stmt to the callback (noting that it's always
passed as the 2nd argument). Any other value triggers an
exception.
- saveSql = an optional array. If set, the SQL of each
executed statement is appended to this array before the
statement is executed (but after it is prepared - we
don't have the string until after that). Empty SQL
statements are elided.
See also the exec() method, which is a close cousin of this
one.
ACHTUNG #1: The callback MUST NOT modify the Stmt
object. Calling any of the Stmt.get() variants,
Stmt.getColumnName(), or similar, is legal, but calling
step() or finalize() is not. Routines which are illegal
in this context will trigger an exception.
ACHTUNG #2: The semantics of the `bind` and `callback`
options may well change or those options may be removed
altogether for this function (but retained for exec()).
Generally speaking, neither bind parameters nor a callback
are generically useful when executing multi-statement SQL.
*/
execMulti: function(/*(sql [,obj]) || (obj)*/){
affirmDbOpen(this);
const arg = (BindTypes===arguments[2]
/* ^^^ Being passed on from exec() */
? arguments[0] : parseExecArgs(arguments));
if(!arg.sql) return this;
const opt = arg.opt;
const stack = stackSave();
let stmt;
let bind = opt.bind;
let rowMode = (
(opt.callback && opt.rowMode)
? opt.rowMode : false);
try{
let pSql = SQM.allocateUTF8OnStack(arg.sql)
const pzTail = stackAlloc(4);
while(getValue(pSql, "i8")){
setValue(pPtrArg, 0, "i32");
setValue(pzTail, 0, "i32");
this.checkRc(api.sqlite3_prepare_v2_sqlptr(
this._pDb, pSql, -1, pPtrArg, pzTail
));
const pStmt = getValue(pPtrArg, "i32");
pSql = getValue(pzTail, "i32");
if(!pStmt) continue;
if(opt.saveSql){
opt.saveSql.push(api.sqlite3_sql(pStmt).trim());
}
stmt = new Stmt(this, pStmt, BindTypes);
if(bind && stmt.parameterCount){
stmt.bind(bind);
bind = null;
}
if(opt.callback && null!==rowMode){
while(stmt.step()){
stmt._isLocked = true;
callback(arg.cbArg(stmt), stmt);
stmt._isLocked = false;
}
rowMode = null;
}else{
// Do we need to while(stmt.step()){} here?
stmt.step();
}
stmt.finalize();
stmt = null;
}
}finally{
if(stmt){
delete stmt._isLocked;
stmt.finalize();
}
stackRestore(stack);
}
return this;
}/*execMulti()*/,
/**
Creates a new scalar UDF (User-Defined Function) which is
accessible via SQL code. This function may be called in any
of the following forms:
- (name, function)
- (name, function, optionsObject)
- (name, optionsObject)
- (optionsObject)
In the final two cases, the function must be defined as the
'callback' property of the options object. In the final
case, the function's name must be the 'name' property.
This can only be used to create scalar functions, not
aggregate or window functions. UDFs cannot be removed from
a DB handle after they're added.
On success, returns this object. Throws on error.
When called from SQL, arguments to the UDF, and its result,
will be converted between JS and SQL with as much fidelity
as is feasible, triggering an exception if a type
conversion cannot be determined. Some freedom is afforded
to numeric conversions due to friction between the JS and C
worlds: integers which are larger than 32 bits will be
treated as doubles, as JS does not support 64-bit integers
and it is (as of this writing) illegal to use WASM
functions which take or return 64-bit integers from JS.
The optional options object may contain flags to modify how
the function is defined:
- .arity: the number of arguments which SQL calls to this
function expect or require. The default value is the
callback's length property (i.e. the number of declared
parameters it has). A value of -1 means that the function
is variadic and may accept any number of arguments, up to
sqlite3's compile-time limits. sqlite3 will enforce the
argument count if is zero or greater.
The following properties correspond to flags documented at:
https://sqlite.org/c3ref/create_function.html
- .deterministic = SQLITE_DETERMINISTIC
- .directOnly = SQLITE_DIRECTONLY
- .innocuous = SQLITE_INNOCUOUS
Maintenance reminder: the ability to add new
WASM-accessible functions to the runtime requires that the
WASM build is compiled with emcc's `-sALLOW_TABLE_GROWTH`
flag.
*/
createFunction: function f(name, callback,opt){
switch(arguments.length){
case 1: /* (optionsObject) */
opt = name;
name = opt.name;
callback = opt.callback;
break;
case 2: /* (name, callback|optionsObject) */
if(!(callback instanceof Function)){
opt = callback;
callback = opt.callback;
}
break;
default: break;
}
if(!opt) opt = {};
if(!(callback instanceof Function)){
toss("Invalid arguments: expecting a callback function.");
}else if('string' !== typeof name){
toss("Invalid arguments: missing function name.");
}
if(!f._extractArgs){
/* Static init */
f._extractArgs = function(argc, pArgv){
let i, pVal, valType, arg;
const tgt = [];
for(i = 0; i < argc; ++i){
pVal = getValue(pArgv + (4 * i), "i32");
valType = api.sqlite3_value_type(pVal);
switch(valType){
case api.SQLITE_INTEGER:
case api.SQLITE_FLOAT:
arg = api.sqlite3_value_double(pVal);
break;
case SQLITE_TEXT:
arg = api.sqlite3_value_text(pVal);
break;
case SQLITE_BLOB:{
const n = api.sqlite3_value_bytes(ptr);
const pBlob = api.sqlite3_value_blob(ptr);
arg = new Uint8Array(n);
let i;
for(i = 0; i < n; ++i) arg[i] = HEAP8[pBlob+i];
break;
}
default:
arg = null; break;
}
tgt.push(arg);
}
return tgt;
}/*_extractArgs()*/;
f._setResult = function(pCx, val){
switch(typeof val) {
case 'boolean':
api.sqlite3_result_int(pCx, val ? 1 : 0);
break;
case 'number': {
(isInt32(val)
? api.sqlite3_result_int
: api.sqlite3_result_double)(pCx, val);
break;
}
case 'string':
api.sqlite3_result_text(pCx, val, -1,
-1/*==SQLITE_TRANSIENT*/);
break;
case 'object':
if(null===val) {
api.sqlite3_result_null(pCx);
break;
}else if(undefined!==val.length){
const pBlob =
SQM.allocate(val, SQM.ALLOC_NORMAL);
api.sqlite3_result_blob(pCx, pBlob, val.length, -1/*==SQLITE_TRANSIENT*/);
SQM._free(blobptr);
break;
}
// else fall through
default:
toss("Don't not how to handle this UDF result value:",val);
};
}/*_setResult()*/;
}/*static init*/
const wrapper = function(pCx, argc, pArgv){
try{
f._setResult(pCx, callback.apply(null, f._extractArgs(argc, pArgv)));
}catch(e){
api.sqlite3_result_error(pCx, e.message, -1);
}
};
const pUdf = SQM.addFunction(wrapper, "viii");
let fFlags = 0;
if(getOwnOption(opt, 'deterministic')) fFlags |= api.SQLITE_DETERMINISTIC;
if(getOwnOption(opt, 'directOnly')) fFlags |= api.SQLITE_DIRECTONLY;
if(getOwnOption(opt, 'innocuous')) fFlags |= api.SQLITE_INNOCUOUS;
name = name.toLowerCase();
try {
this.checkRc(api.sqlite3_create_function_v2(
this._pDb, name,
(opt.hasOwnProperty('arity') ? +opt.arity : callback.length),
api.SQLITE_UTF8 | fFlags, null/*pApp*/, pUdf,
null/*xStep*/, null/*xFinal*/, null/*xDestroy*/));
}catch(e){
SQM.removeFunction(pUdf);
throw e;
}
if(this._udfs.hasOwnProperty(name)){
SQM.removeFunction(this._udfs[name]);
}
this._udfs[name] = pUdf;
return this;
}/*createFunction()*/,
/**
Prepares the given SQL, step()s it one time, and returns
the value of the first result column. If it has no results,
undefined is returned. If passed a second argument, it is
treated like an argument to Stmt.bind(), so may be any type
supported by that function. Throws on error (e.g. malformed
SQL).
*/
selectValue: function(sql,bind){
let stmt, rc;
try {
stmt = this.prepare(sql).bind(bind);
if(stmt.step()) rc = stmt.get(0);
}finally{
if(stmt) stmt.finalize();
}
return rc;
},
/**
Exports a copy of this db's file as a Uint8Array and
returns it. It is technically not legal to call this while
any prepared statement are currently active because,
depending on the platform, it might not be legal to read
the db while a statement is locking it. Throws if this db
is not open or has any opened statements.
The resulting buffer can be passed to this class's
constructor to restore the DB.
Maintenance reminder: the corresponding sql.js impl of this
feature closes the current db, finalizing any active
statements and (seemingly unnecessarily) destroys any UDFs,
copies the file, and then re-opens it (without restoring
the UDFs). Those gymnastics are not necessary on the tested
platform but might be necessary on others. Because of that
eventuality, this interface currently enforces that no
statements are active when this is run. It will throw if
any are.
*/
exportBinaryImage: function(){
affirmDbOpen(this);
if(Object.keys(this._statements).length){
toss("Cannot export with prepared statements active!",
"finalize() all statements and try again.");
}
return FS.readFile(this.filename, {encoding:"binary"});
}
}/*DB.prototype*/;
/** Throws if the given Stmt has been finalized, else stmt is
returned. */
const affirmStmtOpen = function(stmt){
if(!stmt._pStmt) toss("Stmt has been closed.");
return stmt;
};
/** Returns an opaque truthy value from the BindTypes
enum if v's type is a valid bindable type, else
returns a falsy value. As a special case, a value of
undefined is treated as a bind type of null. */
const isSupportedBindType = function(v){
let t = BindTypes[(null===v||undefined===v) ? 'null' : typeof v];
switch(t){
case BindTypes.boolean:
case BindTypes.null:
case BindTypes.number:
case BindTypes.string:
return t;
default:
if(v instanceof Uint8Array) return BindTypes.blob;
return undefined;
}
};
/**
If isSupportedBindType(v) returns a truthy value, this
function returns that value, else it throws.
*/
const affirmSupportedBindType = function(v){
return isSupportedBindType(v) || toss("Unsupport bind() argument type.");
};
/**
If key is a number and within range of stmt's bound parameter
count, key is returned.
If key is not a number then it is checked against named
parameters. If a match is found, its index is returned.
Else it throws.
*/
const affirmParamIndex = function(stmt,key){
const n = ('number'===typeof key)
? key : api.sqlite3_bind_parameter_index(stmt._pStmt, key);
if(0===n || (n===key && (n!==(n|0)/*floating point*/))){
toss("Invalid bind() parameter name: "+key);
}
else if(n<1 || n>stmt.parameterCount) toss("Bind index",key,"is out of range.");
return n;
};
/** Throws if ndx is not an integer or if it is out of range
for stmt.columnCount, else returns stmt.
Reminder: this will also fail after the statement is finalized
but the resulting error will be about an out-of-bounds column
index.
*/
const affirmColIndex = function(stmt,ndx){
if((ndx !== (ndx|0)) || ndx<0 || ndx>=stmt.columnCount){
toss("Column index",ndx,"is out of range.");
}
return stmt;
};
/**
If stmt._isLocked is truthy, this throws an exception
complaining that the 2nd argument (an operation name,
e.g. "bind()") is not legal while the statement is "locked".
Locking happens before an exec()-like callback is passed a
statement, to ensure that the callback does not mutate or
finalize the statement. If it does not throw, it returns stmt.
*/
const affirmUnlocked = function(stmt,currentOpName){
if(stmt._isLocked){
toss("Operation is illegal when statement is locked:",currentOpName);
}
return stmt;
};
/**
Binds a single bound parameter value on the given stmt at the
given index (numeric or named) using the given bindType (see
the BindTypes enum) and value. Throws on error. Returns stmt on
success.
*/
const bindOne = function f(stmt,ndx,bindType,val){
affirmUnlocked(stmt, 'bind()');
if(!f._){
f._ = {
string: function(stmt, ndx, val, asBlob){
const bytes = intArrayFromString(val,true);
const pStr = SQM.allocate(bytes, ALLOC_NORMAL);
stmt._allocs.push(pStr);
const func = asBlob ? api.sqlite3_bind_blob : api.sqlite3_bind_text;
return func(stmt._pStmt, ndx, pStr, bytes.length, 0);
}
};
}
affirmSupportedBindType(val);
ndx = affirmParamIndex(stmt,ndx);
let rc = 0;
switch((null===val || undefined===val) ? BindTypes.null : bindType){
case BindTypes.null:
rc = api.sqlite3_bind_null(stmt._pStmt, ndx);
break;
case BindTypes.string:{
rc = f._.string(stmt, ndx, val, false);
break;
}
case BindTypes.number: {
const m = (isInt32(val)
? api.sqlite3_bind_int
/*It's illegal to bind a 64-bit int
from here*/
: api.sqlite3_bind_double);
rc = m(stmt._pStmt, ndx, val);
break;
}
case BindTypes.boolean:
rc = api.sqlite3_bind_int(stmt._pStmt, ndx, val ? 1 : 0);
break;
case BindTypes.blob: {
if('string'===typeof val){
rc = f._.string(stmt, ndx, val, true);
}else{
const len = val.length;
if(undefined===len){
toss("Binding a value as a blob requires",
"that it have a length member.");
}
const pBlob = SQM.allocate(val, ALLOC_NORMAL);
stmt._allocs.push(pBlob);
rc = api.sqlite3_bind_blob(stmt._pStmt, ndx, pBlob, len, 0);
}
}
default: toss("Unsupported bind() argument type.");
}
if(rc) stmt.db.checkRc(rc);
return stmt;
};
/** Frees any memory explicitly allocated for the given
Stmt object. Returns stmt. */
const freeBindMemory = function(stmt){
let m;
while(undefined !== (m = stmt._allocs.pop())){
SQM._free(m);
}
return stmt;
};
Stmt.prototype = {
/**
"Finalizes" this statement. This is a no-op if the
statement has already been finalizes. Returns
undefined. Most methods in this class will throw if called
after this is.
*/
finalize: function(){
if(this._pStmt){
affirmUnlocked(this,'finalize()');
freeBindMemory(this);
delete this.db._statements[this._pStmt];
api.sqlite3_finalize(this._pStmt);
delete this.columnCount;
delete this.parameterCount;
delete this._pStmt;
delete this.db;
delete this._isLocked;
}
},
/** Clears all bound values. Returns this object.
Throws if this statement has been finalized. */
clearBindings: function(){
freeBindMemory(
affirmUnlocked(affirmStmtOpen(this), 'clearBindings()')
);
api.sqlite3_clear_bindings(this._pStmt);
this._mayGet = false;
return this;
},
/**
Resets this statement so that it may be step()ed again
from the beginning. Returns this object. Throws if this
statement has been finalized.
If passed a truthy argument then this.clearBindings() is
also called, otherwise any existing bindings, along with
any memory allocated for them, are retained.
*/
reset: function(alsoClearBinds){
affirmUnlocked(this,'reset()');
if(alsoClearBinds) this.clearBindings();
api.sqlite3_reset(affirmStmtOpen(this)._pStmt);
this._mayGet = false;
return this;
},
/**
Binds one or more values to its bindable parameters. It
accepts 1 or 2 arguments:
If passed a single argument, it must be either an array, an
object, or a value of a bindable type (see below).
If passed 2 arguments, the first one is the 1-based bind
index or bindable parameter name and the second one must be
a value of a bindable type.
Bindable value types:
- null is bound as NULL.
- undefined as a standalone value is a no-op intended to
simplify certain client-side use cases: passing undefined
as a value to this function will not actually bind
anything and this function will skip confirmation that
binding is even legal. (Those semantics simplify certain
client-side uses.) Conversely, a value of undefined as an
array or object property when binding an array/object
(see below) is treated the same as null.
- Numbers are bound as either doubles or integers: doubles
if they are larger than 32 bits, else double or int32,
depending on whether they have a fractional part. (It is,
as of this writing, illegal to call (from JS) a WASM
function which either takes or returns an int64.)
Booleans are bound as integer 0 or 1. It is not expected
the distinction of binding doubles which have no
fractional parts is integers is significant for the
majority of clients due to sqlite3's data typing
model. This API does not currently support the BigInt
type.
- Strings are bound as strings (use bindAsBlob() to force
blob binding).
- Uint8Array instances are bound as blobs.
If passed an array, each element of the array is bound at
the parameter index equal to the array index plus 1
(because arrays are 0-based but binding is 1-based).
If passed an object, each object key is treated as a
bindable parameter name. The object keys _must_ match any
bindable parameter names, including any `$`, `@`, or `:`
prefix. Because `$` is a legal identifier chararacter in
JavaScript, that is the suggested prefix for bindable
parameters.
It returns this object on success and throws on
error. Errors include:
- Any bind index is out of range, a named bind parameter
does not match, or this statement has no bindable
parameters.
- Any value to bind is of an unsupported type.
- Passed no arguments or more than two.
- The statement has been finalized.
*/
bind: function(/*[ndx,] arg*/){
affirmStmtOpen(this);
let ndx, arg;
switch(arguments.length){
case 1: ndx = 1; arg = arguments[0]; break;
case 2: ndx = arguments[0]; arg = arguments[1]; break;
default: toss("Invalid bind() arguments.");
}
if(undefined===arg){
/* It might seem intuitive to bind undefined as NULL
but this approach simplifies certain client-side
uses when passing on arguments between 2+ levels of
functions. */
return this;
}else if(!this.parameterCount){
toss("This statement has no bindable parameters.");
}
this._mayGet = false;
if(null===arg){
/* bind NULL */
return bindOne(this, ndx, BindTypes.null, arg);
}
else if(Array.isArray(arg)){
/* bind each entry by index */
if(1!==arguments.length){
toss("When binding an array, an index argument is not permitted.");
}
arg.forEach((v,i)=>bindOne(this, i+1, affirmSupportedBindType(v), v));
return this;
}
else if('object'===typeof arg/*null was checked above*/){
/* bind by name */
if(1!==arguments.length){
toss("When binding an object, an index argument is not permitted.");
}
Object.keys(arg)
.forEach(k=>bindOne(this, k,
affirmSupportedBindType(arg[k]),
arg[k]));
return this;
}else{
return bindOne(this, ndx,
affirmSupportedBindType(arg), arg);
}
toss("Should not reach this point.");
},
/**
Special case of bind() which binds the given value
using the BLOB binding mechanism instead of the default
selected one for the value. The ndx may be a numbered
or named bind index. The value must be of type string,
Uint8Array, or null/undefined (both treated as null).
If passed a single argument, a bind index of 1 is assumed.
*/
bindAsBlob: function(ndx,arg){
affirmStmtOpen(this);
if(1===arguments.length){
ndx = 1;
arg = arguments[0];
}
const t = affirmSupportedBindType(arg);
if(BindTypes.string !== t && BindTypes.blob !== t
&& BindTypes.null !== t){
toss("Invalid value type for bindAsBlob()");
}
this._mayGet = false;
return bindOne(this, ndx, BindTypes.blob, arg);
},
/**
Steps the statement one time. If the result indicates that
a row of data is available, true is returned. If no row of
data is available, false is returned. Throws on error.
*/
step: function(){
affirmUnlocked(this, 'step()');
const rc = api.sqlite3_step(affirmStmtOpen(this)._pStmt);
switch(rc){
case api.SQLITE_DONE: return this._mayGet = false;
case api.SQLITE_ROW: return this._mayGet = true;
default:
this._mayGet = false;
console.warn("sqlite3_step() rc=",rc,"SQL =",
api.sqlite3_sql(this._pStmt));
this.db.checkRc(rc);
};
},
/**
Fetches the value from the given 0-based column index of
the current data row, throwing if index is out of range.
Requires that step() has just returned a truthy value, else
an exception is thrown.
By default it will determine the data type of the result
automatically. If passed a second arugment, it must be one
of the enumeration values for sqlite3 types, which are
defined as members of the sqlite3 module: SQLITE_INTEGER,
SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB. Any other value,
except for undefined, will trigger an exception. Passing
undefined is the same as not passing a value. It is legal
to, e.g., fetch an integer value as a string, in which case
sqlite3 will convert the value to a string.
If ndx is an array, this function behaves a differently: it
assigns the indexes of the array, from 0 to the number of
result columns, to the values of the corresponding column,
and returns that array.
If ndx is a plain object, this function behaves even
differentlier: it assigns the properties of the object to
the values of their corresponding result columns.
Blobs are returned as Uint8Array instances.
Potential TODO: add type ID SQLITE_JSON, which fetches the
result as a string and passes it (if it's not null) to
JSON.parse(), returning the result of that. Until then,
getJSON() can be used for that.
*/
get: function(ndx,asType){
if(!affirmStmtOpen(this)._mayGet){
toss("Stmt.step() has not (recently) returned true.");
}
if(Array.isArray(ndx)){
let i = 0;
while(i<this.columnCount){
ndx[i] = this.get(i++);
}
return ndx;
}else if(ndx && 'object'===typeof ndx){
let i = 0;
while(i<this.columnCount){
ndx[api.sqlite3_column_name(this._pStmt,i)] = this.get(i++);
}
return ndx;
}
affirmColIndex(this, ndx);
switch(undefined===asType
? api.sqlite3_column_type(this._pStmt, ndx)
: asType){
case api.SQLITE_NULL: return null;
case api.SQLITE_INTEGER:{
return 0 | api.sqlite3_column_double(this._pStmt, ndx);
/* ^^^^^^^^ strips any fractional part and handles
handles >32bits */
}
case api.SQLITE_FLOAT:
return api.sqlite3_column_double(this._pStmt, ndx);
case api.SQLITE_TEXT:
return api.sqlite3_column_text(this._pStmt, ndx);
case api.SQLITE_BLOB: {
const n = api.sqlite3_column_bytes(this._pStmt, ndx);
const ptr = api.sqlite3_column_blob(this._pStmt, ndx);
const rc = new Uint8Array(n);
for(let i = 0; i < n; ++i) rc[i] = HEAP8[ptr + i];
if(n && this.db._blobXfer instanceof Array){
/* This is an optimization soley for the
Worker-based API. These values will be
transfered to the main thread directly
instead of being copied. */
this.db._blobXfer.push(rc.buffer);
}
return rc;
}
default: toss("Don't know how to translate",
"type of result column #"+ndx+".");
}
abort("Not reached.");
},
/** Equivalent to get(ndx) but coerces the result to an
integer. */
getInt: function(ndx){return this.get(ndx,api.SQLITE_INTEGER)},
/** Equivalent to get(ndx) but coerces the result to a
float. */
getFloat: function(ndx){return this.get(ndx,api.SQLITE_FLOAT)},
/** Equivalent to get(ndx) but coerces the result to a
string. */
getString: function(ndx){return this.get(ndx,api.SQLITE_TEXT)},
/** Equivalent to get(ndx) but coerces the result to a
Uint8Array. */
getBlob: function(ndx){return this.get(ndx,api.SQLITE_BLOB)},
/**
A convenience wrapper around get() which fetches the value
as a string and then, if it is not null, passes it to
JSON.parse(), returning that result. Throws if parsing
fails. If the result is null, null is returned. An empty
string, on the other hand, will trigger an exception.
*/
getJSON: function(ndx){
const s = this.get(ndx, api.SQLITE_STRING);
return null===s ? s : JSON.parse(s);
},
/**
Returns the result column name of the given index, or
throws if index is out of bounds or this statement has been
finalized. This can be used without having run step()
first.
*/
getColumnName: function(ndx){
return api.sqlite3_column_name(
affirmColIndex(affirmStmtOpen(this),ndx)._pStmt, ndx
);
},
/**
If this statement potentially has result columns, this
function returns an array of all such names. If passed an
array, it is used as the target and all names are appended
to it. Returns the target array. Throws if this statement
cannot have result columns. This object's columnCount member
holds the number of columns.
*/
getColumnNames: function(tgt){
affirmColIndex(affirmStmtOpen(this),0);
if(!tgt) tgt = [];
for(let i = 0; i < this.columnCount; ++i){
tgt.push(api.sqlite3_column_name(this._pStmt, i));
}
return tgt;
},
/**
If this statement has named bindable parameters and the
given name matches one, its 1-based bind index is
returned. If no match is found, 0 is returned. If it has no
bindable parameters, the undefined value is returned.
*/
getParamIndex: function(name){
return (affirmStmtOpen(this).parameterCount
? api.sqlite3_bind_parameter_index(this._pStmt, name)
: undefined);
}
}/*Stmt.prototype*/;
/** OO binding's namespace. */
const SQLite3 = {
version: {
lib: api.sqlite3_libversion(),
ooApi: "0.0.1"
},
DB,
Stmt,
/**
Reports info about compile-time options. It has several
distinct uses:
If optName is an array then it is expected to be a list of
compilation options and this function returns an object
which maps each such option to true or false, indicating
whether or not the given option was included in this
build. That object is returned.
If optName is an object, its keys are expected to be
compilation options and this function sets each entry to
true or false. That object is returned.
If passed no arguments then it returns an object mapping
all known compilation options to their compile-time values,
or boolean true if they are defined with no value.
In all other cases it returns true if the given option was
active when when compiling the sqlite3 module, else false.
Compile-time option names may optionally include their
"SQLITE_" prefix. When it returns an object of all options,
the prefix is elided.
*/
compileOptionUsed: function f(optName){
if(!arguments.length){
if(!f._opt){
f._rx = /^([^=]+)=(.+)/;
f._rxInt = /^-?\d+$/;
f._opt = function(opt, rv){
const m = f._rx.exec(opt);
rv[0] = (m ? m[1] : opt);
rv[1] = m ? (f._rxInt.test(m[2]) ? +m[2] : m[2]) : true;
};
}
const rc = {}, ov = [0,0];
let i = 0, k;
while((k = api.sqlite3_compileoption_get(i++))){
f._opt(k,ov);
rc[ov[0]] = ov[1];
}
return rc;
}
else if(Array.isArray(optName)){
const rc = {};
optName.forEach((v)=>{
rc[v] = api.sqlite3_compileoption_used(v);
});
return rc;
}
else if('object' === typeof optName){
Object.keys(optName).forEach((k)=> {
optName[k] = api.sqlite3_compileoption_used(k);
});
return optName;
}
return (
'string'===typeof optName
) ? !!api.sqlite3_compileoption_used(optName) : false;
}
}/*SQLite3 object*/;
namespace.sqlite3 = {
api: api,
SQLite3
};
if(self === self.window){
/* This is running in the main window thread, so we're done. */
setTimeout(()=>postMessage({type:'sqlite3-api',data:'loaded'}), 0);
return;
}
/******************************************************************
End of main window thread. What follows is only intended for use
in Worker threads.
******************************************************************/
/*
UNDER CONSTRUCTION
We need an API which can proxy the DB API via a Worker message
interface. The primary quirky factor in such an API is that we
cannot pass callback functions between the window thread and a
worker thread, so we have to receive all db results via
asynchronous message-passing.
Certain important considerations here include:
- Support only one db connection or multiple? The former is far
easier, but there's always going to be a user out there who
wants to juggle six database handles at once. Do we add that
complexity or tell such users to write their own code using
the provided lower-level APIs?
- Fetching multiple results: do we pass them on as a series of
messages, with start/end messages on either end, or do we
collect all results and bundle them back in a single message?
The former is, generically speaking, more memory-efficient but
the latter far easier to implement in this environment. The
latter is untennable for large data sets. Despite a web page
hypothetically being a relatively limited environment, there
will always be those users who feel that they should/need to
be able to work with multi-hundred-meg (or larger) blobs, and
passing around arrays of those may quickly exhaust the JS
engine's memory.
TODOs include, but are not limited to:
- The ability to manage multiple DB handles. This can
potentially be done via a simple mapping of DB.filename or
DB._pDb (`sqlite3*` handle) to DB objects. The open()
interface would need to provide an ID (probably DB._pDb) back
to the user which can optionally be passed as an argument to
the other APIs (they'd default to the first-opened DB, for
ease of use). Client-side usability of this feature would
benefit from making another wrapper class (or a singleton)
available to the main thread, with that object proxying all(?)
communication with the worker.
- Revisit how virtual files are managed. We currently delete DBs
from the virtual filesystem when we close them, for the sake
of saving memory (the VFS lives in RAM). Supporting multiple
DBs may require that we give up that habit. Similarly, fully
supporting ATTACH, where a user can upload multiple DBs and
ATTACH them, also requires the that we manage the VFS entries
better. As of this writing, ATTACH will fail fatally in the
fiddle app (but not the lower-level APIs) because it runs in
safe mode, where ATTACH is disabled.
*/
/**
Helper for managing Worker-level state.
*/
const wState = {
db: undefined,
open: function(arg){
if(!arg && this.db) return this.db;
else if(this.db) this.db.close();
return this.db = (Array.isArray(arg) ? new DB(...arg) : new DB(arg));
},
close: function(alsoUnlink){
if(this.db){
this.db.close(alsoUnlink);
this.db = undefined;
}
},
affirmOpen: function(){
return this.db || toss("DB is not opened.");
},
post: function(type,data,xferList){
if(xferList){
self.postMessage({type, data},xferList);
xferList.length = 0;
}else{
self.postMessage({type, data});
}
}
};
/**
A level of "organizational abstraction" for the Worker
API. Each method in this object must map directly to a Worker
message type key. The onmessage() dispatcher attempts to
dispatch all inbound messages to a method of this object,
passing it the event.data part of the inbound event object. All
methods must return a plain Object containing any response
state, which the dispatcher may amend. All methods must throw
on error.
*/
const wMsgHandler = {
xfer: [/*Temp holder for "transferable" postMessage() state.*/],
/**
Proxy for DB.exec() which expects a single argument of type
string (SQL to execute) or an options object in the form
expected by exec(). The notable differences from exec()
include:
- The default value for options.rowMode is 'array' because
the normal default cannot cross the window/Worker boundary.
- A function-type options.callback property cannot cross
the window/Worker boundary, so is not useful here. If
options.callback is a string then it is assumed to be a
message type key, in which case a callback function will be
applied which posts each row result via:
postMessage({type: thatKeyType, data: theRow})
And, at the end of the result set (whether or not any
result rows were produced), it will post an identical
message with data:null to alert the caller than the result
set is completed.
The callback proxy must not recurse into this interface, or
results are undefined. (It hypothetically cannot recurse
because an exec() call will be tying up the Worker thread,
causing any recursion attempt to wait until the first
exec() is completed.)
The response is the input options object (or a synthesized
one if passed only a string), noting that
options.resultRows and options.columnNames may be populated
by the call to exec().
This opens/creates the Worker's db if needed.
*/
exec: function(ev){
const opt = (
'string'===typeof ev.data
) ? {sql: ev.data} : (ev.data || {});
if(!opt.rowMode){
/* Since the default rowMode of 'stmt' is not useful
for the Worker interface, we'll default to
something else. */
opt.rowMode = 'array';
}else if('stmt'===opt.rowMode){
toss("Invalid rowMode for exec(): stmt mode",
"does not work in the Worker API.");
}
const db = wState.open();
if(opt.callback || opt.resultRows instanceof Array){
// Part of a copy-avoidance optimization for blobs
db._blobXfer = this.xfer;
}
const callbackMsgType = opt.callback;
if('string' === typeof callbackMsgType){
const that = this;
opt.callback =
(row)=>wState.post(callbackMsgType,row,this.xfer);
}
try {
db.exec(opt);
if(opt.callback instanceof Function){
opt.callback = callbackMsgType;
wState.post(callbackMsgType, null);
}
}finally{
delete db._blobXfer;
if('string'===typeof callbackMsgType){
opt.callback = callbackMsgType;
}
}
return opt;
}/*exec()*/,
/**
Proxy for DB.exportBinaryImage(). Throws if the db has not
been opened. Response is an object:
{
buffer: Uint8Array (db file contents),
filename: the current db filename,
mimetype: string
}
*/
export: function(ev){
const db = wState.affirmOpen();
const response = {
buffer: db.exportBinaryImage(),
filename: db.filename,
mimetype: 'application/x-sqlite3'
};
this.xfer.push(response.buffer.buffer);
return response;
}/*export()*/,
/**
Proxy for the DB constructor. Expects to be passed a single
object or a falsy value to use defaults. The object may
have a filename property to name the db file (see the DB
constructor for peculiarities and transformations) and/or a
buffer property (a Uint8Array holding a complete database
file's contents). The response is an object:
{
filename: db filename (possibly differing from the input)
}
If the Worker's db is currently opened, this call closes it
before proceeding.
*/
open: function(ev){
wState.close(/*true???*/);
const args = [], data = (ev.data || {});
if(data.filename) args.push(data.filename);
if(data.buffer){
args.push(data.buffer);
this.xfer.push(data.buffer.buffer);
}
const db = wState.open(args);
return {filename: db.filename};
},
/**
Proxy for DB.close(). If ev.data may either be a boolean or
an object with an `unlink` property. If that value is
truthy then the db file (if the db is currently open) will
be unlinked from the virtual filesystem, else it will be
kept intact. The response object is:
{filename: db filename _if_ the db is is opened when this
is called, else the undefined value
}
*/
close: function(ev){
const response = {
filename: wState.db && wState.db.filename
};
if(wState.db){
wState.close(!!(ev.data && 'object'===typeof ev.data)
? ev.data.unlink : ev.data);
}
return response;
}
}/*wMsgHandler*/;
/**
UNDER CONSTRUCTION!
A subset of the DB API is accessible via Worker messages in the form:
{ type: apiCommand,
data: apiArguments }
As a rule, these commands respond with a postMessage() of their
own in the same form, but will, if needed, transform the `data`
member to an object and may add state to it. The responses
always have an object-format `data` part. If the inbound `data`
is an object which has a `messageId` property, that property is
always mirrored in the result object, for use in client-side
dispatching of these asynchronous results. Exceptions thrown
during processing result in an `error`-type event with a
payload in the form:
{
message: error string,
errorClass: class name of the error type,
input: ev.data,
[messageId: if set in the inbound message]
}
The individual APIs are documented in the wMsgHandler object.
*/
self.onmessage = function(ev){
ev = ev.data;
let response, evType = ev.type;
try {
if(wMsgHandler.hasOwnProperty(evType) &&
wMsgHandler[evType] instanceof Function){
response = wMsgHandler[evType](ev);
}else{
toss("Unknown db worker message type:",ev.type);
}
}catch(err){
evType = 'error';
response = {
message: err.message,
errorClass: err.name,
input: ev
};
}
if(!response.messageId && ev.data
&& 'object'===typeof ev.data && ev.data.messageId){
response.messageId = ev.data.messageId;
}
wState.post(evType, response, wMsgHandler.xfer);
};
setTimeout(()=>postMessage({type:'sqlite3-api',data:'loaded'}), 0);
});