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Add: aggregate functions. #407

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Add: aggregate functions. #407

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a29cff0
initial commit.
Jul 3, 2020
1de9ec9
Merge branch 'master' into aggregate-functions
lovasoa Jun 2, 2022
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216 changes: 154 additions & 62 deletions src/api.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1131,81 +1131,90 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
return sqlite3_changes(this.db);
};

/** Register a custom function with SQLite
@example Register a simple function
db.create_function("addOne", function (x) {return x+1;})
db.exec("SELECT addOne(1)") // = 2
var extract_blob = function extract_blob(ptr) {
var size = sqlite3_value_bytes(ptr);
var blob_ptr = sqlite3_value_blob(ptr);
var blob_arg = new Uint8Array(size);
for (var j = 0; j < size; j += 1) {
blob_arg[j] = HEAP8[blob_ptr + j];
}
return blob_arg;
};

@param {string} name the name of the function as referenced in
SQL statements.
@param {function} func the actual function to be executed.
@return {Database} The database object. Useful for method chaining
*/
var parseFunctionArguments = function parseFunctionArguments(argc, argv) {
var args = [];
for (var i = 0; i < argc; i += 1) {
var value_ptr = getValue(argv + (4 * i), "i32");
var value_type = sqlite3_value_type(value_ptr);
var arg;
if (
value_type === SQLITE_INTEGER
|| value_type === SQLITE_FLOAT
) {
arg = sqlite3_value_double(value_ptr);
} else if (value_type === SQLITE_TEXT) {
arg = sqlite3_value_text(value_ptr);
} else if (value_type === SQLITE_BLOB) {
arg = extract_blob(value_ptr);
} else arg = null;
args.push(arg);
}
return args;
};
var setFunctionResult = function setFunctionResult(cx, result) {
switch (typeof result) {
case "boolean":
sqlite3_result_int(cx, result ? 1 : 0);
break;
case "number":
sqlite3_result_double(cx, result);
break;
case "string":
sqlite3_result_text(cx, result, -1, -1);
break;
case "object":
if (result === null) {
sqlite3_result_null(cx);
} else if (result.length != null) {
var blobptr = allocate(result, ALLOC_NORMAL);
sqlite3_result_blob(cx, blobptr, result.length, -1);
_free(blobptr);
} else {
sqlite3_result_error(cx, (
"Wrong API use : tried to return a value "
+ "of an unknown type (" + result + ")."
), -1);
}
break;
default:
sqlite3_result_null(cx);
}
};

/** Register a custom function with SQLite
@example Register a simple function
db.create_function("addOne", function (x) {return x+1;})
db.exec("SELECT addOne(1)") // = 2

@param {string} name the name of the function as referenced in
SQL statements.
@param {function} func the actual function to be executed.
@return {Database} The database object. Useful for method chaining
*/
Database.prototype["create_function"] = function create_function(
name,
func
) {
function wrapped_func(cx, argc, argv) {
var args = parseFunctionArguments(argc, argv);
var result;
function extract_blob(ptr) {
var size = sqlite3_value_bytes(ptr);
var blob_ptr = sqlite3_value_blob(ptr);
var blob_arg = new Uint8Array(size);
for (var j = 0; j < size; j += 1) {
blob_arg[j] = HEAP8[blob_ptr + j];
}
return blob_arg;
}
var args = [];
for (var i = 0; i < argc; i += 1) {
var value_ptr = getValue(argv + (4 * i), "i32");
var value_type = sqlite3_value_type(value_ptr);
var arg;
if (
value_type === SQLITE_INTEGER
|| value_type === SQLITE_FLOAT
) {
arg = sqlite3_value_double(value_ptr);
} else if (value_type === SQLITE_TEXT) {
arg = sqlite3_value_text(value_ptr);
} else if (value_type === SQLITE_BLOB) {
arg = extract_blob(value_ptr);
} else arg = null;
args.push(arg);
}
try {
result = func.apply(null, args);
} catch (error) {
sqlite3_result_error(cx, error, -1);
return;
}
switch (typeof result) {
case "boolean":
sqlite3_result_int(cx, result ? 1 : 0);
break;
case "number":
sqlite3_result_double(cx, result);
break;
case "string":
sqlite3_result_text(cx, result, -1, -1);
break;
case "object":
if (result === null) {
sqlite3_result_null(cx);
} else if (result.length != null) {
var blobptr = allocate(result, ALLOC_NORMAL);
sqlite3_result_blob(cx, blobptr, result.length, -1);
_free(blobptr);
} else {
sqlite3_result_error(cx, (
"Wrong API use : tried to return a value "
+ "of an unknown type (" + result + ")."
), -1);
}
break;
default:
sqlite3_result_null(cx);
}
setFunctionResult(cx, result);
}
if (Object.prototype.hasOwnProperty.call(this.functions, name)) {
removeFunction(this.functions[name]);
Expand All @@ -1229,6 +1238,89 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
return this;
};

/** Register a custom aggregate with SQLite
@example Register a aggregate function
db.create_aggregate(
"js_sum",
function () { return { sum: 0 }; },
function (state, value) { state.sum+=value; },
function (state) { return state.sum; }
);
db.exec("CREATE TABLE test (col); INSERT INTO test VALUES (1), (2)");
db.exec("SELECT js_sum(col) FROM test"); // = 3

@param {string} name the name of the aggregate as referenced in
SQL statements.
@param {function} init the actual function to be executed on initialize.
@param {function} step the actual function to be executed on step by step.
@param {function} finalize the actual function to be executed on finalize.
@return {Database} The database object. Useful for method chaining
*/
Database.prototype["create_aggregate"] = function create_aggregate(
name,
init,
step,
finalize
) {
var state;
function wrapped_step(cx, argc, argv) {
if (!state) {
state = init();
}
var args = parseFunctionArguments(argc, argv);
var mergedArgs = [state].concat(args);
try {
step.apply(null, mergedArgs);
} catch (error) {
sqlite3_result_error(cx, error, -1);
}
}
function wrapped_finalize(cx) {
var result;
try {
result = finalize.apply(null, [state]);
} catch (error) {
sqlite3_result_error(cx, error, -1);
state = null;
return;
}
setFunctionResult(cx, result);
state = null;
}

if (Object.prototype.hasOwnProperty.call(this.functions, name)) {
removeFunction(this.functions[name]);
delete this.functions[name];
}
if (Object.prototype.hasOwnProperty.call(
this.functions,
name + "__finalize"
)) {
removeFunction(this.functions[name + "__finalize"]);
delete this.functions[name + "__finalize"];
}
// The signature of the wrapped function is :
// void wrapped(sqlite3_context *db, int argc, sqlite3_value **argv)
var step_ptr = addFunction(wrapped_step, "viii");
// The signature of the wrapped function is :
// void wrapped(sqlite3_context *db)
var finalize_ptr = addFunction(wrapped_finalize, "vi");
this.functions[name] = step_ptr;
this.functions[name + "__finalize"] = finalize_ptr;
this.handleError(sqlite3_create_function_v2(
this.db,
name,
step.length - 1,
SQLITE_UTF8,
0,
0,
step_ptr,
finalize_ptr,
0
));
return this;
};

// export Database to Module
Module.Database = Database;
};
17 changes: 17 additions & 0 deletions test/test_aggregate_functions.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
exports.test = function (SQL, assert) {
var db = new SQL.Database();

db.create_aggregate(
"js_sum",
function () { return { sum: 0 }; },
function (state, value) { state.sum += value; },
function (state) { return state.sum; }
);

db.exec("CREATE TABLE test (col);");
db.exec("INSERT INTO test VALUES (1), (2), (3);");
var result = db.exec("SELECT js_sum(col) FROM test;");
assert.equal(result[0].values[0][0], 6, "Simple aggregate function.");

// TODO: Add test cases..
}