From 96a9fa9101e9ed50149d284ff32c361084223fa4 Mon Sep 17 00:00:00 2001
From: Adam Kocoloski <adam@cloudant.com>
Date: Mon, 23 Aug 2010 13:51:50 -0400
Subject: consolidate all couchjs stuff in one subdir

---
 couchjs/js/views.js | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 couchjs/js/views.js

(limited to 'couchjs/js/views.js')

diff --git a/couchjs/js/views.js b/couchjs/js/views.js
new file mode 100644
index 00000000..ffe63377
--- /dev/null
+++ b/couchjs/js/views.js
@@ -0,0 +1,137 @@
+// 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 = Couch.toJSON(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
+      // ]
+      //
+
+      /*
+      Immutable document support temporarily removed.
+
+      Removed because the seal function no longer works on JS 1.8 arrays,
+      instead returning an error. The sealing is meant to prevent map
+      functions from modifying the same document that is passed to other map
+      functions. However, only map functions in the same design document are
+      run together, so we have a reasonable expectation they can trust each
+      other. Any map fun that can't be trusted can be placed in its own
+      design document, and it cannot affect other map functions.
+
+      recursivelySeal(doc); // seal to prevent map functions from changing doc
+      */
+      var buf = [];
+      for (var i = 0; i < State.funs.length; i++) {
+        map_results = [];
+        try {
+          State.funs[i](doc);
+          buf.push(Couch.toJSON(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("[" + buf.join(", ") + "]");
+    }
+  }
+})();
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