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// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
var Views = (function() {
var map_results = []; // holds temporary emitted values during doc map
function runReduce(reduceFuns, keys, values, rereduce) {
for (var i in reduceFuns) {
reduceFuns[i] = Couch.compileFunction(reduceFuns[i]);
};
var reductions = new Array(reduceFuns.length);
for(var i = 0; i < reduceFuns.length; i++) {
try {
reductions[i] = reduceFuns[i](keys, values, rereduce);
} catch (err) {
handleViewError(err);
// if the error is not fatal, ignore the results and continue
reductions[i] = null;
}
};
var reduce_line = JSON.stringify(reductions);
var reduce_length = reduce_line.length;
// TODO make reduce_limit config into a number
if (State.query_config && State.query_config.reduce_limit &&
reduce_length > 200 && ((reduce_length * 2) > State.line_length)) {
var reduce_preview = "Current output: '"+(reduce_line.substring(0,100) + "'... (first 100 of "+reduce_length+" bytes)");
throw(["error",
"reduce_overflow_error",
"Reduce output must shrink more rapidly: "+reduce_preview]);
} else {
print("[true," + reduce_line + "]");
}
};
function handleViewError(err, doc) {
if (err == "fatal_error") {
// Only if it's a "fatal_error" do we exit. What's a fatal error?
// That's for the query to decide.
//
// This will make it possible for queries to completely error out,
// by catching their own local exception and rethrowing a
// fatal_error. But by default if they don't do error handling we
// just eat the exception and carry on.
//
// In this case we abort map processing but don't destroy the
// JavaScript process. If you need to destroy the JavaScript
// process, throw the error form matched by the block below.
throw(["error", "map_runtime_error", "function raised 'fatal_error'"]);
} else if (err[0] == "fatal") {
// Throwing errors of the form ["fatal","error_key","reason"]
// will kill the OS process. This is not normally what you want.
throw(err);
}
var message = "function raised exception " + err.toSource();
if (doc) message += " with doc._id " + doc._id;
log(message);
};
return {
// view helper functions
emit : function(key, value) {
map_results.push([key, value]);
},
sum : function(values) {
var rv = 0;
for (var i in values) {
rv += values[i];
}
return rv;
},
reduce : function(reduceFuns, kvs) {
var keys = new Array(kvs.length);
var values = new Array(kvs.length);
for(var i = 0; i < kvs.length; i++) {
keys[i] = kvs[i][0];
values[i] = kvs[i][1];
}
runReduce(reduceFuns, keys, values, false);
},
rereduce : function(reduceFuns, values) {
runReduce(reduceFuns, null, values, true);
},
mapDoc : function(doc) {
// Compute all the map functions against the document.
//
// Each function can output multiple key/value pairs for each document.
//
// Example output of map_doc after three functions set by add_fun cmds:
// [
// [["Key","Value"]], <- fun 1 returned 1 key value
// [], <- fun 2 returned 0 key values
// [["Key1","Value1"],["Key2","Value2"]] <- fun 3 returned 2 key values
// ]
//
Couch.recursivelySeal(doc);
var buf = [];
for each (fun in State.funs) {
map_results = [];
try {
fun(doc);
buf.push(map_results);
} catch (err) {
handleViewError(err, doc);
// If the error is not fatal, we treat the doc as if it
// did not emit anything, by buffering an empty array.
buf.push([]);
}
}
print(JSON.stringify(buf));
}
}
})();
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