Adding upstream version 9.0.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>

1 files changed, 469 insertions, 0 deletions

diff --git a/services/gitdiff/csv.go b/services/gitdiff/csv.go
new file mode 100644
index 0000000..8db73c5
--- /dev/null
+++ b/services/gitdiff/csv.go
@@ -0,0 +1,469 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitdiff
+
+import (
+	"encoding/csv"
+	"errors"
+	"io"
+)
+
+const (
+	unmappedColumn           = -1
+	maxRowsToInspect int     = 10
+	minRatioToMatch  float32 = 0.8
+)
+
+// TableDiffCellType represents the type of a TableDiffCell.
+type TableDiffCellType uint8
+
+// TableDiffCellType possible values.
+const (
+	TableDiffCellUnchanged TableDiffCellType = iota + 1
+	TableDiffCellChanged
+	TableDiffCellAdd
+	TableDiffCellDel
+	TableDiffCellMovedUnchanged
+	TableDiffCellMovedChanged
+)
+
+// TableDiffCell represents a cell of a TableDiffRow
+type TableDiffCell struct {
+	LeftCell  string
+	RightCell string
+	Type      TableDiffCellType
+}
+
+// TableDiffRow represents a row of a TableDiffSection.
+type TableDiffRow struct {
+	RowIdx int
+	Cells  []*TableDiffCell
+}
+
+// TableDiffSection represents a section of a DiffFile.
+type TableDiffSection struct {
+	Rows []*TableDiffRow
+}
+
+// csvReader wraps a csv.Reader which buffers the first rows.
+type csvReader struct {
+	reader *csv.Reader
+	buffer [][]string
+	line   int
+	eof    bool
+}
+
+// ErrorUndefinedCell is for when a row, column coordinates do not exist in the CSV
+var ErrorUndefinedCell = errors.New("undefined cell")
+
+// createCsvReader creates a csvReader and fills the buffer
+func createCsvReader(reader *csv.Reader, bufferRowCount int) (*csvReader, error) {
+	csv := &csvReader{reader: reader}
+	csv.buffer = make([][]string, bufferRowCount)
+	for i := 0; i < bufferRowCount && !csv.eof; i++ {
+		row, err := csv.readNextRow()
+		if err != nil {
+			return nil, err
+		}
+		csv.buffer[i] = row
+	}
+	csv.line = bufferRowCount
+	return csv, nil
+}
+
+// GetRow gets a row from the buffer if present or advances the reader to the requested row. On the end of the file only nil gets returned.
+func (csv *csvReader) GetRow(row int) ([]string, error) {
+	if row < len(csv.buffer) && row >= 0 {
+		return csv.buffer[row], nil
+	}
+	if csv.eof {
+		return nil, nil
+	}
+	for {
+		fields, err := csv.readNextRow()
+		if err != nil {
+			return nil, err
+		}
+		if csv.eof {
+			return nil, nil
+		}
+		csv.line++
+		if csv.line-1 == row {
+			return fields, nil
+		}
+	}
+}
+
+func (csv *csvReader) readNextRow() ([]string, error) {
+	if csv.eof {
+		return nil, nil
+	}
+	row, err := csv.reader.Read()
+	if err != nil {
+		if err != io.EOF {
+			return nil, err
+		}
+		csv.eof = true
+	}
+	return row, nil
+}
+
+// CreateCsvDiff creates a tabular diff based on two CSV readers.
+func CreateCsvDiff(diffFile *DiffFile, baseReader, headReader *csv.Reader) ([]*TableDiffSection, error) {
+	if baseReader != nil && headReader != nil {
+		return createCsvDiff(diffFile, baseReader, headReader)
+	}
+
+	if baseReader != nil {
+		return createCsvDiffSingle(baseReader, TableDiffCellDel)
+	}
+	return createCsvDiffSingle(headReader, TableDiffCellAdd)
+}
+
+// createCsvDiffSingle creates a tabular diff based on a single CSV reader. All cells are added or deleted.
+func createCsvDiffSingle(reader *csv.Reader, celltype TableDiffCellType) ([]*TableDiffSection, error) {
+	var rows []*TableDiffRow
+	i := 1
+	for {
+		row, err := reader.Read()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, err
+		}
+		cells := make([]*TableDiffCell, len(row))
+		for j := 0; j < len(row); j++ {
+			if celltype == TableDiffCellDel {
+				cells[j] = &TableDiffCell{LeftCell: row[j], Type: celltype}
+			} else {
+				cells[j] = &TableDiffCell{RightCell: row[j], Type: celltype}
+			}
+		}
+		rows = append(rows, &TableDiffRow{RowIdx: i, Cells: cells})
+		i++
+	}
+
+	return []*TableDiffSection{{Rows: rows}}, nil
+}
+
+func createCsvDiff(diffFile *DiffFile, baseReader, headReader *csv.Reader) ([]*TableDiffSection, error) {
+	// Given the baseReader and headReader, we are going to create CSV Reader for each, baseCSVReader and b respectively
+	baseCSVReader, err := createCsvReader(baseReader, maxRowsToInspect)
+	if err != nil {
+		return nil, err
+	}
+	headCSVReader, err := createCsvReader(headReader, maxRowsToInspect)
+	if err != nil {
+		return nil, err
+	}
+
+	// Initializing the mappings of base to head (a2bColMap) and head to base (b2aColMap) columns
+	a2bColMap, b2aColMap := getColumnMapping(baseCSVReader, headCSVReader)
+
+	// Determines how many cols there will be in the diff table, which includes deleted columns from base and added columns to base
+	numDiffTableCols := len(a2bColMap) + countUnmappedColumns(b2aColMap)
+	if len(a2bColMap) < len(b2aColMap) {
+		numDiffTableCols = len(b2aColMap) + countUnmappedColumns(a2bColMap)
+	}
+
+	// createDiffTableRow takes the row # of the `a` line and `b` line of a diff (starting from 1), 0 if the line doesn't exist (undefined)
+	// in the base or head respectively.
+	// Returns a TableDiffRow which has the row index
+	createDiffTableRow := func(aLineNum, bLineNum int) (*TableDiffRow, error) {
+		// diffTableCells is a row of the diff table. It will have a cells for added, deleted, changed, and unchanged content, thus either
+		// the same size as the head table or bigger
+		diffTableCells := make([]*TableDiffCell, numDiffTableCols)
+		var bRow *[]string
+		if bLineNum > 0 {
+			row, err := headCSVReader.GetRow(bLineNum - 1)
+			if err != nil {
+				return nil, err
+			}
+			bRow = &row
+		}
+		var aRow *[]string
+		if aLineNum > 0 {
+			row, err := baseCSVReader.GetRow(aLineNum - 1)
+			if err != nil {
+				return nil, err
+			}
+			aRow = &row
+		}
+		if aRow == nil && bRow == nil {
+			// No content
+			return nil, nil
+		}
+
+		aIndex := 0      // tracks where we are in the a2bColMap
+		bIndex := 0      // tracks where we are in the b2aColMap
+		colsAdded := 0   // incremented whenever we found a column was added
+		colsDeleted := 0 // incrememted whenever a column was deleted
+
+		// We loop until both the aIndex and bIndex are greater than their col map, which then we are done
+		for aIndex < len(a2bColMap) || bIndex < len(b2aColMap) {
+			// Starting from where aIndex is currently pointing, we see if the map is -1 (dleeted) and if is, create column to note that, increment, and look at the next aIndex
+			for aIndex < len(a2bColMap) && a2bColMap[aIndex] == -1 && (bIndex >= len(b2aColMap) || aIndex <= bIndex) {
+				var aCell string
+				if aRow != nil {
+					if cell, err := getCell(*aRow, aIndex); err != nil {
+						if err != ErrorUndefinedCell {
+							return nil, err
+						}
+					} else {
+						aCell = cell
+					}
+				}
+				diffTableCells[bIndex+colsDeleted] = &TableDiffCell{LeftCell: aCell, Type: TableDiffCellDel}
+				aIndex++
+				colsDeleted++
+			}
+
+			// aIndex is now pointing to a column that also exists in b, or is at the end of a2bColMap. If the former,
+			// we can just increment aIndex until it points to a -1 column or one greater than the current bIndex
+			for aIndex < len(a2bColMap) && a2bColMap[aIndex] != -1 {
+				aIndex++
+			}
+
+			// Starting from where bIndex is currently pointing, we see if the map is -1 (added) and if is, create column to note that, increment, and look at the next aIndex
+			for bIndex < len(b2aColMap) && b2aColMap[bIndex] == -1 && (aIndex >= len(a2bColMap) || bIndex < aIndex) {
+				var bCell string
+				cellType := TableDiffCellAdd
+				if bRow != nil {
+					if cell, err := getCell(*bRow, bIndex); err != nil {
+						if err != ErrorUndefinedCell {
+							return nil, err
+						}
+					} else {
+						bCell = cell
+					}
+				} else {
+					cellType = TableDiffCellDel
+				}
+				diffTableCells[bIndex+colsDeleted] = &TableDiffCell{RightCell: bCell, Type: cellType}
+				bIndex++
+				colsAdded++
+			}
+
+			// aIndex is now pointing to a column that also exists in a, or is at the end of b2aColMap. If the former,
+			// we get the a col and b col values (if they exist), figure out if they are the same or not, and if the column moved, and add it to the diff table
+			for bIndex < len(b2aColMap) && b2aColMap[bIndex] != -1 && (aIndex >= len(a2bColMap) || bIndex < aIndex) {
+				var diffTableCell TableDiffCell
+
+				var aCell *string
+				// get the aCell value if the aRow exists
+				if aRow != nil {
+					if cell, err := getCell(*aRow, b2aColMap[bIndex]); err != nil {
+						if err != ErrorUndefinedCell {
+							return nil, err
+						}
+					} else {
+						aCell = &cell
+						diffTableCell.LeftCell = cell
+					}
+				} else {
+					diffTableCell.Type = TableDiffCellAdd
+				}
+
+				var bCell *string
+				// get the bCell value if the bRow exists
+				if bRow != nil {
+					if cell, err := getCell(*bRow, bIndex); err != nil {
+						if err != ErrorUndefinedCell {
+							return nil, err
+						}
+					} else {
+						bCell = &cell
+						diffTableCell.RightCell = cell
+					}
+				} else {
+					diffTableCell.Type = TableDiffCellDel
+				}
+
+				// if both a and b have a row that exists, compare the value and determine if the row has moved
+				if aCell != nil && bCell != nil {
+					moved := ((bIndex + colsDeleted) != (b2aColMap[bIndex] + colsAdded))
+					if *aCell != *bCell {
+						if moved {
+							diffTableCell.Type = TableDiffCellMovedChanged
+						} else {
+							diffTableCell.Type = TableDiffCellChanged
+						}
+					} else {
+						if moved {
+							diffTableCell.Type = TableDiffCellMovedUnchanged
+						} else {
+							diffTableCell.Type = TableDiffCellUnchanged
+						}
+						diffTableCell.LeftCell = ""
+					}
+				}
+
+				// Add the diff column to the diff row
+				diffTableCells[bIndex+colsDeleted] = &diffTableCell
+				bIndex++
+			}
+		}
+
+		return &TableDiffRow{RowIdx: bLineNum, Cells: diffTableCells}, nil
+	}
+
+	// diffTableSections are TableDiffSections which represent the diffTableSections we get when doing a diff, each will be its own table in the view
+	var diffTableSections []*TableDiffSection
+
+	for i, section := range diffFile.Sections {
+		// Each section has multiple diffTableRows
+		var diffTableRows []*TableDiffRow
+		lines := tryMergeLines(section.Lines)
+		// Loop through the merged lines to get each row of the CSV diff table for this section
+		for j, line := range lines {
+			if i == 0 && j == 0 && (line[0] != 1 || line[1] != 1) {
+				diffTableRow, err := createDiffTableRow(1, 1)
+				if err != nil {
+					return nil, err
+				}
+				if diffTableRow != nil {
+					diffTableRows = append(diffTableRows, diffTableRow)
+				}
+			}
+			diffTableRow, err := createDiffTableRow(line[0], line[1])
+			if err != nil {
+				return nil, err
+			}
+			if diffTableRow != nil {
+				diffTableRows = append(diffTableRows, diffTableRow)
+			}
+		}
+
+		if len(diffTableRows) > 0 {
+			diffTableSections = append(diffTableSections, &TableDiffSection{Rows: diffTableRows})
+		}
+	}
+
+	return diffTableSections, nil
+}
+
+// getColumnMapping creates a mapping of columns between a and b
+func getColumnMapping(baseCSVReader, headCSVReader *csvReader) ([]int, []int) {
+	baseRow, _ := baseCSVReader.GetRow(0)
+	headRow, _ := headCSVReader.GetRow(0)
+
+	base2HeadColMap := []int{}
+	head2BaseColMap := []int{}
+
+	if baseRow != nil {
+		base2HeadColMap = make([]int, len(baseRow))
+	}
+	if headRow != nil {
+		head2BaseColMap = make([]int, len(headRow))
+	}
+
+	// Initializes all head2base mappings to be unmappedColumn (-1)
+	for i := 0; i < len(head2BaseColMap); i++ {
+		head2BaseColMap[i] = unmappedColumn
+	}
+
+	// Loops through the baseRow and see if there is a match in the head row
+	for i := 0; i < len(baseRow); i++ {
+		base2HeadColMap[i] = unmappedColumn
+		baseCell, err := getCell(baseRow, i)
+		if err == nil {
+			for j := 0; j < len(headRow); j++ {
+				if head2BaseColMap[j] == -1 {
+					headCell, err := getCell(headRow, j)
+					if err == nil && baseCell == headCell {
+						base2HeadColMap[i] = j
+						head2BaseColMap[j] = i
+						break
+					}
+				}
+			}
+		}
+	}
+
+	tryMapColumnsByContent(baseCSVReader, base2HeadColMap, headCSVReader, head2BaseColMap)
+	tryMapColumnsByContent(headCSVReader, head2BaseColMap, baseCSVReader, base2HeadColMap)
+
+	return base2HeadColMap, head2BaseColMap
+}
+
+// tryMapColumnsByContent tries to map missing columns by the content of the first lines.
+func tryMapColumnsByContent(baseCSVReader *csvReader, base2HeadColMap []int, headCSVReader *csvReader, head2BaseColMap []int) {
+	for i := 0; i < len(base2HeadColMap); i++ {
+		headStart := 0
+		for base2HeadColMap[i] == unmappedColumn && headStart < len(head2BaseColMap) {
+			if head2BaseColMap[headStart] == unmappedColumn {
+				rows := min(maxRowsToInspect, max(0, min(len(baseCSVReader.buffer), len(headCSVReader.buffer))-1))
+				same := 0
+				for j := 1; j <= rows; j++ {
+					baseCell, baseErr := getCell(baseCSVReader.buffer[j], i)
+					headCell, headErr := getCell(headCSVReader.buffer[j], headStart)
+					if baseErr == nil && headErr == nil && baseCell == headCell {
+						same++
+					}
+				}
+				if (float32(same) / float32(rows)) > minRatioToMatch {
+					base2HeadColMap[i] = headStart
+					head2BaseColMap[headStart] = i
+				}
+			}
+			headStart++
+		}
+	}
+}
+
+// getCell returns the specific cell or nil if not present.
+func getCell(row []string, column int) (string, error) {
+	if column < len(row) {
+		return row[column], nil
+	}
+	return "", ErrorUndefinedCell
+}
+
+// countUnmappedColumns returns the count of unmapped columns.
+func countUnmappedColumns(mapping []int) int {
+	count := 0
+	for i := 0; i < len(mapping); i++ {
+		if mapping[i] == unmappedColumn {
+			count++
+		}
+	}
+	return count
+}
+
+// tryMergeLines maps the separated line numbers of a git diff. The result is assumed to be ordered.
+func tryMergeLines(lines []*DiffLine) [][2]int {
+	ids := make([][2]int, len(lines))
+
+	i := 0
+	for _, line := range lines {
+		if line.Type != DiffLineSection {
+			ids[i][0] = line.LeftIdx
+			ids[i][1] = line.RightIdx
+			i++
+		}
+	}
+
+	ids = ids[:i]
+
+	result := make([][2]int, len(ids))
+
+	j := 0
+	for i = 0; i < len(ids); i++ {
+		if ids[i][0] == 0 {
+			if j > 0 && result[j-1][1] == 0 {
+				temp := j
+				for temp > 0 && result[temp-1][1] == 0 {
+					temp--
+				}
+				result[temp][1] = ids[i][1]
+				continue
+			}
+		}
+		result[j] = ids[i]
+		j++
+	}
+
+	return result[:j]
+}