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Diffstat (limited to 'src/ext_depends/D-YAML/source/dyaml/composer.d')
| -rw-r--r-- | src/ext_depends/D-YAML/source/dyaml/composer.d | 375 |
1 files changed, 375 insertions, 0 deletions
diff --git a/src/ext_depends/D-YAML/source/dyaml/composer.d b/src/ext_depends/D-YAML/source/dyaml/composer.d new file mode 100644 index 0000000..c000b02 --- /dev/null +++ b/src/ext_depends/D-YAML/source/dyaml/composer.d @@ -0,0 +1,375 @@ + +// Copyright Ferdinand Majerech 2011. +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) + +/** + * Composes nodes from YAML events provided by parser. + * Code based on PyYAML: http://www.pyyaml.org + */ +module dyaml.composer; + +import core.memory; + +import std.algorithm; +import std.array; +import std.conv; +import std.exception; +import std.range; +import std.typecons; + +import dyaml.constructor; +import dyaml.event; +import dyaml.exception; +import dyaml.node; +import dyaml.parser; +import dyaml.resolver; + + +package: +/** + * Exception thrown at composer errors. + * + * See_Also: MarkedYAMLException + */ +class ComposerException : MarkedYAMLException +{ + mixin MarkedExceptionCtors; +} + +///Composes YAML documents from events provided by a Parser. +struct Composer +{ + private: + ///Parser providing YAML events. + Parser parser_; + ///Resolver resolving tags (data types). + Resolver resolver_; + ///Nodes associated with anchors. Used by YAML aliases. + Node[string] anchors_; + + ///Used to reduce allocations when creating pair arrays. + /// + ///We need one appender for each nesting level that involves + ///a pair array, as the inner levels are processed as a + ///part of the outer levels. Used as a stack. + Appender!(Node.Pair[])[] pairAppenders_; + ///Used to reduce allocations when creating node arrays. + /// + ///We need one appender for each nesting level that involves + ///a node array, as the inner levels are processed as a + ///part of the outer levels. Used as a stack. + Appender!(Node[])[] nodeAppenders_; + + public: + /** + * Construct a composer. + * + * Params: parser = Parser to provide YAML events. + * resolver = Resolver to resolve tags (data types). + */ + this(Parser parser, Resolver resolver) @safe + { + parser_ = parser; + resolver_ = resolver; + } + + /** + * Determine if there are any nodes left. + * + * Must be called before loading as it handles the stream start event. + */ + bool checkNode() @safe + { + // If next event is stream start, skip it + parser_.skipOver!"a.id == b"(EventID.streamStart); + + //True if there are more documents available. + return parser_.front.id != EventID.streamEnd; + } + + ///Get a YAML document as a node (the root of the document). + Node getNode() @safe + { + //Get the root node of the next document. + assert(parser_.front.id != EventID.streamEnd, + "Trying to get a node from Composer when there is no node to " ~ + "get. use checkNode() to determine if there is a node."); + + return composeDocument(); + } + + private: + + void skipExpected(const EventID id) @safe + { + const foundExpected = parser_.skipOver!"a.id == b"(id); + assert(foundExpected, text("Expected ", id, " not found.")); + } + ///Ensure that appenders for specified nesting levels exist. + /// + ///Params: pairAppenderLevel = Current level in the pair appender stack. + /// nodeAppenderLevel = Current level the node appender stack. + void ensureAppendersExist(const uint pairAppenderLevel, const uint nodeAppenderLevel) + @safe + { + while(pairAppenders_.length <= pairAppenderLevel) + { + pairAppenders_ ~= appender!(Node.Pair[])(); + } + while(nodeAppenders_.length <= nodeAppenderLevel) + { + nodeAppenders_ ~= appender!(Node[])(); + } + } + + ///Compose a YAML document and return its root node. + Node composeDocument() @safe + { + skipExpected(EventID.documentStart); + + //Compose the root node. + Node node = composeNode(0, 0); + + skipExpected(EventID.documentEnd); + + anchors_.destroy(); + return node; + } + + /// Compose a node. + /// + /// Params: pairAppenderLevel = Current level of the pair appender stack. + /// nodeAppenderLevel = Current level of the node appender stack. + Node composeNode(const uint pairAppenderLevel, const uint nodeAppenderLevel) @safe + { + if(parser_.front.id == EventID.alias_) + { + const event = parser_.front; + parser_.popFront(); + const anchor = event.anchor; + enforce((anchor in anchors_) !is null, + new ComposerException("Found undefined alias: " ~ anchor, + event.startMark)); + + //If the node referenced by the anchor is uninitialized, + //it's not finished, i.e. we're currently composing it + //and trying to use it recursively here. + enforce(anchors_[anchor] != Node(), + new ComposerException("Found recursive alias: " ~ anchor, + event.startMark)); + + return anchors_[anchor]; + } + + const event = parser_.front; + const anchor = event.anchor; + if((anchor !is null) && (anchor in anchors_) !is null) + { + throw new ComposerException("Found duplicate anchor: " ~ anchor, + event.startMark); + } + + Node result; + //Associate the anchor, if any, with an uninitialized node. + //used to detect duplicate and recursive anchors. + if(anchor !is null) + { + anchors_[anchor] = Node(); + } + + switch (parser_.front.id) + { + case EventID.scalar: + result = composeScalarNode(); + break; + case EventID.sequenceStart: + result = composeSequenceNode(pairAppenderLevel, nodeAppenderLevel); + break; + case EventID.mappingStart: + result = composeMappingNode(pairAppenderLevel, nodeAppenderLevel); + break; + default: assert(false, "This code should never be reached"); + } + + if(anchor !is null) + { + anchors_[anchor] = result; + } + return result; + } + + ///Compose a scalar node. + Node composeScalarNode() @safe + { + const event = parser_.front; + parser_.popFront(); + const tag = resolver_.resolve(NodeID.scalar, event.tag, event.value, + event.implicit); + + Node node = constructNode(event.startMark, event.endMark, tag, + event.value); + node.scalarStyle = event.scalarStyle; + + return node; + } + + /// Compose a sequence node. + /// + /// Params: pairAppenderLevel = Current level of the pair appender stack. + /// nodeAppenderLevel = Current level of the node appender stack. + Node composeSequenceNode(const uint pairAppenderLevel, const uint nodeAppenderLevel) + @safe + { + ensureAppendersExist(pairAppenderLevel, nodeAppenderLevel); + auto nodeAppender = &(nodeAppenders_[nodeAppenderLevel]); + + const startEvent = parser_.front; + parser_.popFront(); + const tag = resolver_.resolve(NodeID.sequence, startEvent.tag, null, + startEvent.implicit); + + while(parser_.front.id != EventID.sequenceEnd) + { + nodeAppender.put(composeNode(pairAppenderLevel, nodeAppenderLevel + 1)); + } + + Node node = constructNode(startEvent.startMark, parser_.front.endMark, + tag, nodeAppender.data.dup); + node.collectionStyle = startEvent.collectionStyle; + parser_.popFront(); + nodeAppender.clear(); + + return node; + } + + /** + * Flatten a node, merging it with nodes referenced through YAMLMerge data type. + * + * Node must be a mapping or a sequence of mappings. + * + * Params: root = Node to flatten. + * startMark = Start position of the node. + * endMark = End position of the node. + * pairAppenderLevel = Current level of the pair appender stack. + * nodeAppenderLevel = Current level of the node appender stack. + * + * Returns: Flattened mapping as pairs. + */ + Node.Pair[] flatten(ref Node root, const Mark startMark, const Mark endMark, + const uint pairAppenderLevel, const uint nodeAppenderLevel) @safe + { + void error(Node node) + { + //this is Composer, but the code is related to Constructor. + throw new ConstructorException("While constructing a mapping, " ~ + "expected a mapping or a list of " ~ + "mappings for merging, but found: " ~ + text(node.type) ~ + " NOTE: line/column shows topmost parent " ~ + "to which the content is being merged", + startMark, endMark); + } + + ensureAppendersExist(pairAppenderLevel, nodeAppenderLevel); + auto pairAppender = &(pairAppenders_[pairAppenderLevel]); + + final switch (root.nodeID) + { + case NodeID.mapping: + Node[] toMerge; + toMerge.reserve(root.length); + foreach (ref Node key, ref Node value; root) + { + if(key.type == NodeType.merge) + { + toMerge ~= value; + } + else + { + auto temp = Node.Pair(key, value); + pairAppender.put(temp); + } + } + foreach (node; toMerge) + { + pairAppender.put(flatten(node, startMark, endMark, + pairAppenderLevel + 1, nodeAppenderLevel)); + } + break; + case NodeID.sequence: + foreach (ref Node node; root) + { + if (node.nodeID != NodeID.mapping) + { + error(node); + } + pairAppender.put(flatten(node, startMark, endMark, + pairAppenderLevel + 1, nodeAppenderLevel)); + } + break; + case NodeID.scalar: + case NodeID.invalid: + error(root); + break; + } + + auto flattened = pairAppender.data.dup; + pairAppender.clear(); + + return flattened; + } + + /// Compose a mapping node. + /// + /// Params: pairAppenderLevel = Current level of the pair appender stack. + /// nodeAppenderLevel = Current level of the node appender stack. + Node composeMappingNode(const uint pairAppenderLevel, const uint nodeAppenderLevel) + @safe + { + ensureAppendersExist(pairAppenderLevel, nodeAppenderLevel); + const startEvent = parser_.front; + parser_.popFront(); + const tag = resolver_.resolve(NodeID.mapping, startEvent.tag, null, + startEvent.implicit); + auto pairAppender = &(pairAppenders_[pairAppenderLevel]); + + Tuple!(Node, Mark)[] toMerge; + while(parser_.front.id != EventID.mappingEnd) + { + auto pair = Node.Pair(composeNode(pairAppenderLevel + 1, nodeAppenderLevel), + composeNode(pairAppenderLevel + 1, nodeAppenderLevel)); + + //Need to flatten and merge the node referred by YAMLMerge. + if(pair.key.type == NodeType.merge) + { + toMerge ~= tuple(pair.value, cast(Mark)parser_.front.endMark); + } + //Not YAMLMerge, just add the pair. + else + { + pairAppender.put(pair); + } + } + foreach(node; toMerge) + { + merge(*pairAppender, flatten(node[0], startEvent.startMark, node[1], + pairAppenderLevel + 1, nodeAppenderLevel)); + } + auto numUnique = pairAppender.data.dup + .sort!((x,y) => x.key > y.key) + .uniq!((x,y) => x.key == y.key) + .walkLength; + enforce(numUnique == pairAppender.data.length, + new ComposerException("Duplicate key found in mapping", parser_.front.startMark)); + + Node node = constructNode(startEvent.startMark, parser_.front.endMark, + tag, pairAppender.data.dup); + node.collectionStyle = startEvent.collectionStyle; + parser_.popFront(); + + pairAppender.clear(); + return node; + } +} |