find local usage of symbol located at cursor

(partially based on unmainted PR 202)

.gitignore

@@ -5,8 +5,7 @@
 *.dll
 
 # *nix binaries
-bin/dcd-client
-bin/dcd-server
+bin
 *.o
 *.a
 *.so

README.md

@@ -213,6 +213,27 @@ in place of a file being edited.)
 /usr/include/dmd/phobos/std/conv.d  f   9494
 ```
 
+## Find usage of symbol at cursor
+```dcd-client --localUsage -c 123```
+
+The "--localUsage" or "-u" flags cause the client to instruct the server
+to return all the local usages of the symbol located at the given cursor position.
+
+#### Output format
+When usages exist, if the source symbol is an identifier (a type, a variable name, etc.) and if the symbol is not ambiguous then
+the first line contains the location of the symbol (a file name or literally _stdin_), a tab then the offset to the symbol declaration,
+each following line contains a byte offset, always relative to the supplied file, to a usage of the symbol.
+
+Otherwise the client outputs _00000_ so that the length of the answer is guaranteed to be at least 5 bytes.
+
+#### Example output
+```
+stdin 45
+26
+45
+133
+```
+
 #Server
 The server must be running for the DCD client to provide autocomplete information.
 In future versions the client may start the server if it is not running, but for

src/client/client.d

@@ -50,6 +50,7 @@ int main(string[] args)
 	bool printVersion;
 	bool listImports;
 	bool getIdentifier;
+	bool localUsage;
 	string search;
 	version(Windows)
 	{
@@ -70,7 +71,8 @@ int main(string[] args)
 			"doc|d", &doc, "query|status|q", &query, "search|s", &search,
 			"version", &printVersion, "listImports", &listImports,
 			"tcp", &useTCP, "socketFile", &socketFile,
-			"getIdentifier", &getIdentifier);
+			"getIdentifier", &getIdentifier,
+			"localUsage|u", &localUsage);
 	}
 	catch (ConvException e)
 	{
@@ -212,6 +214,8 @@ int main(string[] args)
 		request.kind |= RequestKind.doc;
 	else if (search)
 		request.kind |= RequestKind.search;
+	else if(localUsage)
+		request.kind |= RequestKind.localUsage;
 	else
 		request.kind |= RequestKind.autocomplete;
 
@@ -231,6 +235,8 @@ int main(string[] args)
 		printDocResponse(response);
 	else if (search !is null)
 		printSearchResponse(response);
+	else if (localUsage)
+		printLocalUsage(response);
 	else
 		printCompletionResponse(response);
 
@@ -277,6 +283,10 @@ Options:
         Searches for symbolName in both stdin / the given file name as well as
         others files cached by the server.
 
+    --localUsage | -u
+        Searches for all the usages of the symbol at the cursor location
+        in the given filename (or stdin).
+
     --query | -q | --status
         Query the server statis. Returns 0 if the server is running. Returns
         1 if the server could not be contacted.
@@ -385,6 +395,17 @@ void printSearchResponse(const AutocompleteResponse response)
 	}
 }
 
+void printLocalUsage(const AutocompleteResponse response)
+{
+	if (response.symbolFilePath.length)
+	{
+		writeln(response.symbolFilePath, '\t', response.symbolLocation);
+		foreach(loc; response.locations)
+			writeln(loc);
+	}
+	else write("00000");
+}
+
 void printImportList(const AutocompleteResponse response)
 {
 	import std.algorithm.iteration : each;

src/common/messages.d

@@ -74,6 +74,8 @@ enum RequestKind : ushort
 	search =         0b00000000_10000000,
 	/// List import directories
 	listImports =    0b00000001_00000000,
+	/// local symbol usage
+	localUsage =     0b00000010_00000000,
 	// dfmt on
 }
 

src/server/autocomplete.d

@@ -50,6 +50,93 @@ import common.messages;
 
 import containers.hashset;
 
+/**
+ * Finds usage of the symbol at the cursor position in a single document.
+ * Params:
+ *     request = the autocompletion request
+ * Returns:
+ *     the autocompletion response
+ */
+public AutocompleteResponse findLocalUsage(AutocompleteRequest request,
+    ref ModuleCache moduleCache)
+{
+    AutocompleteResponse response;
+    RollbackAllocator rba;
+    auto allocator = scoped!(ASTAllocator)();
+    auto cache = StringCache(StringCache.defaultBucketCount);
+
+    // patchs the original request for the subsequent requests
+    request.kind = RequestKind.symbolLocation;
+
+    // getSymbolsForCompletion() copy to avoid repetitive parsing
+    LexerConfig config;
+    config.fileName = "";
+    const(Token)[] tokenArray = getTokensForParser(cast(ubyte[]) request.sourceCode,
+            config, &cache);
+    SymbolStuff getSymbolsAtCursor(size_t cursorPosition)
+    {
+        auto sortedTokens = assumeSorted(tokenArray);
+        auto beforeTokens = sortedTokens.lowerBound(cursorPosition);
+        ScopeSymbolPair pair = generateAutocompleteTrees(tokenArray, allocator,
+            &rba, request.cursorPosition, moduleCache);
+        auto expression = getExpression(beforeTokens);
+        return SymbolStuff(getSymbolsByTokenChain(pair.scope_, expression,
+            cursorPosition, CompletionType.location), pair.symbol, pair.scope_);
+    }
+
+    // gets the symbol matching to cursor pos
+    SymbolStuff stuff = getSymbolsAtCursor(cast(size_t)request.cursorPosition);
+    scope(exit) stuff.destroy();
+
+    // starts searching only if no ambiguity with the symbol
+    if (stuff.symbols.length == 1)
+    {
+        const(DSymbol*) sourceSymbol = stuff.symbols[0];
+        response.symbolLocation = sourceSymbol.location;
+        response.symbolFilePath = sourceSymbol.symbolFile.idup;
+
+        // gets the source token to avoid too much getSymbolsAtCursor()
+        const(Token)* sourceToken;
+        foreach(i, t; tokenArray)
+        {
+            if (t.type != tok!"identifier")
+                continue;
+            if (request.cursorPosition >= t.index &&
+                request.cursorPosition < t.index + t.text.length)
+            {
+                sourceToken = tokenArray.ptr + i;
+                break;
+            }
+        }
+
+        // finds the tokens that match to the source symbol
+        if (sourceToken != null) foreach (t; tokenArray)
+        {
+            if (t.type == tok!"identifier" && t.text == sourceToken.text)
+            {
+                size_t pos = cast(size_t) t.index + 1; // place cursor inside the token
+                SymbolStuff candidate = getSymbolsAtCursor(pos);
+                scope(exit) candidate.destroy();
+                if (candidate.symbols.length == 1 &&
+                    candidate.symbols[0].location == sourceSymbol.location &&
+                    candidate.symbols[0].symbolFile == sourceSymbol.symbolFile)
+                {
+                    response.locations ~= t.index;
+                }
+            }
+        }
+        else
+        {
+            warning("The source token is not an identifier");
+        }
+    }
+    else
+    {
+        warning("No or ambiguous symbol for the identifier at cursor");
+    }
+    return response;
+}
+
 /**
  * Gets documentation for the symbol at the cursor
  * Params:

src/server/server.d

@@ -318,6 +318,19 @@ int main(string[] args)
 			ubyte[] responseBytes = msgpack.pack(response);
 			s.send(responseBytes);
 		}
+        else if (request.kind & RequestKind.localUsage)
+        {
+            try
+            {
+                AutocompleteResponse response = findLocalUsage(request, cache);
+                ubyte[] responseBytes = msgpack.pack(response);
+                s.send(responseBytes);
+            }
+            catch (Exception e)
+            {
+                warning("Could not find local usage", e.msg);
+            }
+        }
 		info("Request processed in ", requestWatch.peek().to!("msecs", float), " milliseconds");
 	}
 	return 0;

tests/tc033/expected1.txt

@@ -0,0 +1,5 @@
+stdin	5
+5
+21
+27
+33

tests/tc033/file.d

@@ -0,0 +1 @@
+uint var; void foo(){var=0;var=0;var=0;}

tests/tc033/run.sh

@@ -0,0 +1,5 @@
+set -e
+set -u
+
+../../bin/dcd-client $1 file.d -u -c22 | sed s\""$(dirname "$(pwd)")"\"\" > actual1.txt
+diff actual1.txt expected1.txt

tests/tc034/expected1.txt

@@ -0,0 +1,3 @@
+/imports/object.d	22
+0
+12

tests/tc034/file.d

@@ -0,0 +1 @@
+string str; string txt;

tests/tc034/run.sh

@@ -0,0 +1,5 @@
+set -e
+set -u
+
+../../bin/dcd-client $1 file.d -u -c1 | sed s\""$(dirname "$(pwd)")"\"\" > actual1.txt
+diff actual1.txt expected1.txt

tests/tc035/expected1.txt

@@ -0,0 +1 @@
+00000

tests/tc035/file.d

@@ -0,0 +1 @@
+struct Foo; struct Foo;

tests/tc035/run.sh

@@ -0,0 +1,5 @@
+set -e
+set -u
+
+../../bin/dcd-client $1 file.d -u -c8 | sed s\""$(dirname "$(pwd)")"\"\" > actual1.txt
+diff actual1.txt expected1.txt