Improved search query parser

libgenapps · Jan 1, 2018 · f8e6edc · f8e6edc
1 parent ee27a6b
commit f8e6edc
Show file tree

Hide file tree

Showing 3 changed files with 125 additions and 23 deletions.
diff --git a/LibgenDesktop.csproj b/LibgenDesktop.csproj
@@ -95,6 +95,7 @@
     <Compile Include="Infrastructure\ViewModelEvent.cs" />
     <Compile Include="Infrastructure\WindowContext.cs" />
     <Compile Include="Infrastructure\WindowManager.cs" />
+    <Compile Include="Models\Database\SearchQueryParser.cs" />
     <Compile Include="Models\Entities\DatabaseMetadata.cs" />
     <Compile Include="Models\Entities\FictionBook.cs" />
     <Compile Include="Models\Entities\SciMagArticle.cs" />

diff --git a/Models/Database/LocalDatabase.cs b/Models/Database/LocalDatabase.cs
@@ -773,29 +773,7 @@ private SciMagArticle ReadSciMagArticle(SQLiteDataReader dataReader)
 
         private string EscapeSearchQuery(string originalSearchQuery)
         {
-            List<string> searchQueryBuilder = new List<string>();
-            foreach (string searchQueryPart in originalSearchQuery.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries))
-            {
-                switch (searchQueryPart)
-                {
-                    case "AND":
-                    case "OR":
-                    case "NOT":
-                        searchQueryBuilder.Add(searchQueryPart);
-                        continue;
-                    default:
-                        if (searchQueryPart.Length > 1 && searchQueryPart.EndsWith("*"))
-                        {
-                            searchQueryBuilder.Add($"\"{searchQueryPart.Substring(0, searchQueryPart.Length - 1)}\"*");
-                        }
-                        else
-                        {
-                            searchQueryBuilder.Add($"\"{searchQueryPart}\"");
-                        }
-                        break;
-                }
-            }
-            return String.Join(" ", searchQueryBuilder);
+            return SearchQueryParser.GetEscapedQuery(originalSearchQuery);
         }
 
         private string GetSearchCommandWithLimit(string searchCommand, int? resultLimit)

diff --git a/Models/Database/SearchQueryParser.cs b/Models/Database/SearchQueryParser.cs
@@ -0,0 +1,123 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace LibgenDesktop.Models.Database
+{
+    internal class SearchQueryParser
+    {
+        private readonly string originalSearchQuery;
+
+        private SearchQueryParser(string originalSearchQuery)
+        {
+            this.originalSearchQuery = originalSearchQuery;
+        }
+
+        public static string GetEscapedQuery(string originalSearchQuery)
+        {
+            return new SearchQueryParser(originalSearchQuery).GetEscapedQuery();
+        }
+
+        private string GetEscapedQuery()
+        {
+            List<string> searchQueryBuilder = new List<string>();
+            bool isInQuotes = false;
+            int currentIndex = 0;
+            string currentQueryPart = String.Empty;
+            while (currentIndex < originalSearchQuery.Length)
+            {
+                char currentChar = originalSearchQuery[currentIndex];
+                switch (currentChar)
+                {
+                    case '"':
+                        if (isInQuotes)
+                        {
+                            currentQueryPart += currentChar;
+                            isInQuotes = false;
+                            if ((currentIndex < originalSearchQuery.Length - 1) && (originalSearchQuery[currentIndex + 1] == '*'))
+                            {
+                                currentIndex++;
+                                currentQueryPart += '*';
+                            }
+                            if (currentQueryPart.Length > 0)
+                            {
+                                AddSearchQueryPart(searchQueryBuilder, currentQueryPart);
+                                currentQueryPart = String.Empty;
+                            }
+                        }
+                        else
+                        {
+                            if (currentQueryPart.Length > 0)
+                            {
+                                AddSearchQueryPart(searchQueryBuilder, currentQueryPart);
+                            }
+                            currentQueryPart = currentChar.ToString();
+                            isInQuotes = true;
+                        }
+                        break;
+                    case ' ':
+                        if (isInQuotes)
+                        {
+                            currentQueryPart += currentChar;
+                        }
+                        else
+                        {
+                            if (currentQueryPart.Length > 0)
+                            {
+                                AddSearchQueryPart(searchQueryBuilder, currentQueryPart);
+                                currentQueryPart = String.Empty;
+                            }
+                        }
+                        break;
+                    default:
+                        currentQueryPart += currentChar;
+                        break;
+                }
+                currentIndex++;
+            }
+            if (currentQueryPart.Length > 0)
+            {
+                if (isInQuotes)
+                {
+                    currentQueryPart = currentQueryPart.Substring(1);
+                }
+                foreach (string remainingQueryPart in currentQueryPart.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries))
+                {
+                    AddSearchQueryPart(searchQueryBuilder, remainingQueryPart);
+                }
+            }
+            return String.Join(" ", searchQueryBuilder);
+        }
+
+        private void AddSearchQueryPart(List<string> searchQueryBuilder, string searchQueryPart)
+        {
+            if (searchQueryPart.StartsWith("\""))
+            {
+                searchQueryBuilder.Add(searchQueryPart);
+            }
+            else
+            {
+                switch (searchQueryPart)
+                {
+                    case "AND":
+                    case "OR":
+                    case "NOT":
+                        searchQueryBuilder.Add(searchQueryPart);
+                        break;
+                    default:
+                        if (searchQueryPart.Length > 1 && searchQueryPart.EndsWith("*"))
+                        {
+                            searchQueryBuilder.Add($"\"{searchQueryPart.Substring(0, searchQueryPart.Length - 1)}\"*");
+                        }
+                        else
+                        {
+                            searchQueryBuilder.Add($"\"{searchQueryPart}\"");
+                        }
+                        break;
+                }
+            }
+        }
+    }
+}