Src/DiffItem.h

   1 /**
   2  *  @file DiffItem.h
   3  *
   4  *  @brief Declaration of DIFFITEM
   5  */
   6 #pragma once
   7
   8 #include "DiffFileInfo.h"
   9
  10 /**
  11  * @brief Bitfield values for binary file sides.
  12  * These values are used as bitfield values when determining which file(s)
  13  * are binary files. There is no "both" -value since in bitfield "both" is
  14  * when side1- and side2- bits are set (BINFILE_SIDE1 | BINFILE_SIDE2).
  15  */
  16 enum BINFILE_SIDE
  17 {
  18         BINFILE_NONE = 0, /**< No binary files detected. */
  19         BINFILE_SIDE1, /**< First file was detected as binary file. */
  20         BINFILE_SIDE2, /**< Second file was detected as binart file. */
  21 };
  22
  23 /**
  24  * @brief Status of one item comparison, stored as bitfields
  25  *
  26  * Bitmask can be seen as a 4 dimensional space; that is, there are four
  27  * different attributes, and each entry picks one of each attribute
  28  * independently.
  29  *
  30  * One dimension is how the compare went: same or different or
  31  * skipped or error.
  32  *
  33  * One dimension is file mode: text or binary (text is only if
  34  * both sides were text)
  35  *
  36  * One dimension is existence: both sides, left only, or right only
  37  *
  38  * One dimension is type: directory, or file
  39  */
  40 struct DIFFCODE
  41 {
  42         /**
  43          * @brief values for DIFFITEM.diffcode
  44          */
  45         enum : unsigned long
  46         {
  47                 // We use extra bits so that no valid values are 0
  48                 // and each set of flags is in a different hex digit
  49                 // to make debugging easier
  50                 // These can always be packed down in the future
  51                 TEXTFLAGS=0x3FU, TEXT=0x1U, BIN=0x2U, BINSIDE1=0x4U, BINSIDE2=0x8U, BINSIDE3=0x10U, IMAGE=0x20U,
  52                 TYPEFLAGS=0xC0U, FILE=0x40U, DIR=0x80U,
  53                 COMPAREFLAGS=0x7000U, NOCMP=0x0000U, DIFF=0x1000U, SAME=0x2000U, CMPERR=0x3000U, CMPABORT=0x4000U,
  54                 COMPAREFLAGS3WAY=0x18000U, DIFFALL=0x0000U, DIFF1STONLY=0x8000U, DIFF2NDONLY=0x10000U, DIFF3RDONLY=0x18000U,
  55                 FILTERFLAGS=0x20000U, INCLUDED=0x00000U, SKIPPED=0x20000U,
  56                 SCANFLAGS=0x100000U, NEEDSCAN=0x100000U,
  57                 THREEWAYFLAGS=0x200000U, THREEWAY=0x200000U,
  58                 SIDEFLAGS=0x70000000U, FIRST=0x10000000U, SECOND=0x20000000U, THIRD=0x40000000U, BOTH=0x30000000U, ALL=0x70000000U,
  59         };
  60
  61         unsigned diffcode;
  62
  63         explicit DIFFCODE(unsigned diffcode = 0) : diffcode(diffcode) { }
  64
  65 protected:
  66         /// Worker function, to check one area (mask) of code for a particular value (result)
  67         static bool Check(unsigned code, unsigned mask, unsigned result) { return ((code & mask) == result); }
  68         /// Convenience function to check the part of the code for comparison results
  69         static bool CheckCompare(unsigned code, unsigned result) { return Check(code, DIFFCODE::COMPAREFLAGS, result); }
  70         /// Convenience function to check the part of the code for filter status
  71         static bool CheckFilter(unsigned code, unsigned result) { return Check(code, DIFFCODE::FILTERFLAGS, result); }
  72         /// Convenience function to check the part of the code for side status (eg, left-only)
  73         static bool CheckSide(unsigned code, unsigned result) { return Check(code, DIFFCODE::SIDEFLAGS, result); }
  74
  75         /// Worker function to set the area indicated by mask to specified result
  76         void Set(int mask, unsigned result) { diffcode &= (~mask); diffcode |= result; }
  77         /// Convenience function to set the side status, eg, SetSide(DIFFCODE::LEFT)
  78         void SetSide(unsigned result) { Set(DIFFCODE::SIDEFLAGS, result); }
  79 public:
  80
  81         // file/directory
  82         bool isDirectory() const { return Check(diffcode, DIFFCODE::TYPEFLAGS, DIFFCODE::DIR); }
  83         // left/right
  84         bool isSideFirstOnly() const { return CheckSide(diffcode, DIFFCODE::FIRST); }
  85         bool isSideSecondOnly() const { return CheckSide(diffcode, DIFFCODE::SECOND); }
  86         bool isSideThirdOnly() const { return CheckSide(diffcode, DIFFCODE::THIRD); }
  87         bool isMissingFirstOnly() const { return CheckSide(diffcode, DIFFCODE::SECOND | DIFFCODE::THIRD); }
  88         bool isMissingSecondOnly() const { return CheckSide(diffcode, DIFFCODE::FIRST | DIFFCODE::THIRD); }
  89         bool isMissingThirdOnly() const { return CheckSide(diffcode, DIFFCODE::FIRST | DIFFCODE::SECOND); }
  90         bool isSideBoth() const { return CheckSide(diffcode, DIFFCODE::BOTH); }
  91         bool isSideAll() const { return CheckSide(diffcode, DIFFCODE::ALL); }
  92         void setSideNone() { SetSide(0); }
  93         void setSideFlag(int nIndex)
  94         {
  95                 switch (nIndex)
  96                 {
  97                 case 0: SetSide(diffcode | DIFFCODE::FIRST); return;
  98                 case 1: SetSide(diffcode | DIFFCODE::SECOND); return;
  99                 case 2: SetSide(diffcode | DIFFCODE::THIRD); return;
 100                 }
 101         }
 102         void unsetSideFlag(int nIndex)
 103         {
 104                 switch (nIndex)
 105                 {
 106                 case 0: SetSide(diffcode & ~DIFFCODE::FIRST); return;
 107                 case 1: SetSide(diffcode & ~DIFFCODE::SECOND); return;
 108                 case 2: SetSide(diffcode & ~DIFFCODE::THIRD); return;
 109                 }
 110         }
 111         bool isSideOnly(int nIndex) const
 112         {
 113                 switch (nIndex)
 114                 {
 115                 case 0: return isSideFirstOnly();
 116                 case 1: return isSideSecondOnly();
 117                 case 2: return isSideThirdOnly();
 118                 default: return 0;
 119                 }
 120         }
 121         bool existsFirst() const { return !!(diffcode & DIFFCODE::FIRST); }
 122         bool existsSecond() const { return !!(diffcode & DIFFCODE::SECOND); }
 123         bool existsThird() const { return !!(diffcode & DIFFCODE::THIRD); }
 124         bool exists(int nIndex) const
 125         {
 126                 switch (nIndex)
 127                 {
 128                 case 0: return !!(diffcode & DIFFCODE::FIRST);
 129                 case 1: return !!(diffcode & DIFFCODE::SECOND);
 130                 case 2: return !!(diffcode & DIFFCODE::THIRD);
 131                 default: return 0;
 132                 }
 133         }
 134         bool existAll() const
 135         {
 136                 if ((diffcode & DIFFCODE::THREEWAY) == 0)
 137                         return (existsFirst() && existsSecond());
 138                 else
 139                         return (existsFirst() && existsSecond() && existsThird());
 140         }
 141
 142         // compare result
 143         bool isResultSame() const { return CheckCompare(diffcode, DIFFCODE::SAME); }
 144         bool isResultDiff() const { return (CheckCompare(diffcode, DIFFCODE::DIFF) && !isResultFiltered() &&
 145                         existAll()); }
 146         static bool isResultError(unsigned code) { return CheckCompare(code, DIFFCODE::CMPERR); }
 147         bool isResultError() const { return isResultError(diffcode); }
 148         static bool isResultAbort(unsigned code) { return CheckCompare(code, DIFFCODE::CMPABORT); }
 149         bool isResultAbort() const { return isResultAbort(diffcode); }
 150         // filter status
 151         bool isResultFiltered() const { return CheckFilter(diffcode, DIFFCODE::SKIPPED); }
 152         // type
 153         bool isText() const { return Check(diffcode, DIFFCODE::TEXTFLAGS, DIFFCODE::TEXT); }
 154         bool isBin() const { return (diffcode & DIFFCODE::BIN) != 0; }
 155         bool isImage() const { return (diffcode & DIFFCODE::IMAGE) != 0; }
 156         // rescan
 157         bool isScanNeeded() const { return ((diffcode & DIFFCODE::SCANFLAGS) == DIFFCODE::NEEDSCAN); }
 158
 159         void swap(int idx1, int idx2);
 160 };
 161
 162 enum ViewCustomFlags
 163 {
 164         // No valid values are 0
 165         INVALID_CODE = 0,
 166         VISIBILITY = 0x3U, VISIBLE = 0x1U, HIDDEN = 0x2U, EXPANDED = 0x4U
 167 };
 168
 169 /**
 170  * @brief information about one file/folder item.
 171  * This class holds information about one compared "item" in the folder comparison tree.
 172  * The item can be a file item or folder item.  The item can have data from
 173  * both (or all three) compare sides (file/folder exists in all sides) or from
 174  * fewer sides (file/folder is missing in one/two sides).
 175  *
 176  * The basic structure consists of linkage to the `parent` folder and possible "sibling"
 177  * file/folder items that share the identical `parent` folder item.  Folder items also
 178  * have a `children` link indicating the head of another DIFFITEM list of contained
 179  * files/folders.
 180  *
 181  * This class is for backend differences processing, representing physical
 182  * files and folders. This class is not for GUI data like selection or
 183  * visibility statuses. So do not include any GUI-dependent data here.
 184  */
 185
 186 // See http://web.eecs.utk.edu/~bvz/teaching/cs140Fa09/notes/Dllists for a discussion of
 187 // "doubly linked lists".  The "sibling" linkage used here is basically a doubly linked
 188 // list (similar to what is described in that article), with the notes ...
 189 //              A. Items may be deleted anywhere within the tree (e.g. via "Refresh Selected (ctrl-F5)").
 190 //                      This justifies the usage of a double link list.
 191 //              B. Lists are only traversed in the forward direction (using `Flink`).  Using `nullptr`
 192 //                      to stop this traversal is both obvious and convenient.
 193 //              C. Items are only inserted at the end, so storing the end's link (for a future insertion)
 194 //                      into the head's `Blink` serves the function of the "sentinel node" without consuming
 195 //                      extra space.
 196 //              D. A "sentinel" structure is not necessary because ...
 197 //                      D1. The head of a sibling list can always be found directly from the parent folder
 198 //                              item by `this->children`.  From an arbitrary sibling item, the head is at
 199 //                              `this->parent->children` .
 200 //                      D2. Similarily, the end of a sibling list is found (from the parent folder item) at
 201 //                              `this->children->Blink` or (from a sibling item) at `this->parent->children->Blink`.
 202 //              E. The "root" item for a DIFFITEM tree is `m_pRoot`, declared in and managed by the
 203 //                      DiffItemList class.  There is one "root" for each active folder comparison
 204 //                      (i.e. each folder comparison window in the GUI).  The "root" item exists to anchor the
 205 //                      tree, as well as to guarantee that the `parent` and `children` linkage is correct at the
 206 //                      top folder comparison level.
 207 //
 208 //
 209 // Sometimes a picture is worth many words...
 210 //
 211 // |------P1-------|
 212 // | "parent item" |
 213 // | parent -------|---> P0
 214 // | Blink & Flink |
 215 // | children -----|->\
 216 // |---------------|  |
 217 //                    |
 218 //                    |  /--------------------------------------------------------------------------->\
 219 //                    |  |                                                                            |
 220 //                    |  |   |---P1.C0-----|           |---P1.S1-----|           |---P1.S2-----|      |
 221 //                    |  |   | data values |           | data values |           | data values |      |
 222 //                    |  |   |-------------|           |-------------|           |-------------|      |
 223 //                    |  \<--|--Blink      |<----------|--Blink      |<----------|--Blink      |<-----/
 224 //                    |      |  Flink -----|---------->|  Flink -----|---------->|  Flink -----|--------> `nullptr`
 225 //                    \----->|  children---|->\        |  children---|->\        |  children---|->\
 226 //            P1<------------|--parent     |  |   P1<--|--parent     |  |   P1<--|--parent     |  |
 227 //                           |-------------|  |        |-------------|  |        |-------------|  |
 228 //                                            |                         |                         |
 229 //                                            \--> P1.C0.C0             \--> P1.S1.C0             \--> P1.S2.C0
 230 //                                            \--> `nullptr`            \--> `nullptr`            \--> `nullptr`
 231 //
 232
 233 class DIFFITEM
 234 {
 235 //**** DIFFITEM data values
 236
 237 public:
 238         DiffFileInfo diffFileInfo[3];   /**< Fileinfo for left/middle/right file. */
 239         int     nsdiffs;                                        /**< Amount of non-ignored differences */
 240         int nidiffs;                                    /**< Amount of ignored differences */
 241                                                                         // Note: Keep `diffFileInfo[]`, `nsdiffs` and `nidiffs`
 242                                                                         //               near front of class for small offsets.
 243                                                                         // (see `DirColInfo` arrays in `DirViewColItems.cpp`) *>
 244         DIFFCODE diffcode;                              /**< Compare result */
 245         unsigned customFlags;                   /**< ViewCustomFlags flags */
 246
 247         String getFilepath(int nIndex, const String &sRoot) const;
 248         void Swap(int idx1, int idx2);
 249
 250 //**** Child, Parent, Sibling linkage
 251 private:                                                        // Don't allow direct external manipulation of link values
 252         DIFFITEM *parent;                               /**< Parent of current item */
 253         DIFFITEM *children;                             /**< Link to first child of this item */
 254         DIFFITEM *Flink;                                /**< Forward "sibling" link.  The forward linkage ends with
 255                                                                                  a `nullptr` in the final (newest) item. */
 256         DIFFITEM *Blink;                                /**< Backward "sibling" link.  The backward linkage is circular,
 257                                                                                  with the first (oldest) item (pointed to by `this->parent->children`)
 258                                                                                  pointing to the last (newest) item. This is for easy insertion. */
 259         void AppendSibling(DIFFITEM *p);
 260
 261 public:
 262         void DelinkFromSiblings();
 263         void AddChildToParent(DIFFITEM *p);
 264         void RemoveChildren();
 265         int GetDepth() const;
 266         bool IsAncestor(const DIFFITEM *pdi) const;
 267         inline DIFFITEM *GetFwdSiblingLink() const { return Flink; }
 268         inline DIFFITEM *GetFirstChild() const { return children; }
 269         inline DIFFITEM *GetParentLink() const { return parent; }
 270
 271         /** @brief Return whether the current DIFFITEM has children */
 272         inline bool DIFFITEM::HasChildren() const { return (children != nullptr); }
 273         /** @brief Return whether the current DIFFITEM has children */
 274         inline bool DIFFITEM::HasParent() const { return (parent != nullptr); }
 275
 276 //**** The `emptyitem` and its access procedures
 277 private:
 278         static DIFFITEM emptyitem;              /**< Singleton to represent a DIFFITEM that doesn't have any data */
 279
 280 public:
 281         static DIFFITEM *GetEmptyItem();
 282         inline bool isEmpty() const { return this == GetEmptyItem(); /* to invoke "emptiness" checking */ }
 283
 284 //**** CTOR, DTOR
 285 public:
 286         DIFFITEM() : parent(nullptr), children(nullptr), Flink(nullptr), Blink(nullptr),
 287                                         nidiffs(-1), nsdiffs(-1), customFlags(ViewCustomFlags::INVALID_CODE)
 288                                         // `DiffFileInfo` and `DIFFCODE` have their own initializers.
 289                                         {}
 290         ~DIFFITEM();
 291
 292 };