genesi

4 files changed, 446 insertions, 0 deletions

diff --git a/document/annot.go b/document/annot.go
new file mode 100644
index 0000000..e280cd0
--- /dev/null
+++ b/document/annot.go
@@ -0,0 +1,76 @@
+package document
+
+import (
+	"github.com/scrotadamus/ghligh/go-poppler"
+)
+
+type AnnotJSON struct {
+	Type		poppler.AnnotType	`json:"type,omitempty"`
+	Index		int			`json:"index,omitempty"`
+	Date		string			`json:"date,omitempty"`
+	Rect		poppler.Rectangle	`json:"rect,omitempty"`
+	Color		poppler.Color		`json:"color,omitempty"`
+	Name		string			`json:"name,omitempty"`
+	Contents	string			`json:"contents,omitempty"`
+	Flags		poppler.AnnotFlag	`json:"flags,omitempty"`
+	Quads		[]poppler.Quad		`json:"quads,omitempty"`
+}
+
+func annotToJson(a poppler.Annot) (AnnotJSON) {
+	var aj AnnotJSON
+	aj.Type = a.Type()
+	aj.Index = a.Index()
+	aj.Date = a.Date()
+	aj.Rect = a.Rect()
+	aj.Color = a.Color()
+	aj.Name = a.Name()
+	aj.Contents = a.Contents()
+	aj.Flags = a.Flags()
+	aj.Quads = a.Quads()
+
+	return aj
+}
+
+func (d *GhlighDoc) jsonToAnnot(aJson AnnotJSON) *poppler.Annot {
+
+	annot, _ := d.doc.NewAnnot(poppler.AnnotHighlight, aJson.Rect, aJson.Quads)
+
+	annot.SetColor(aJson.Color)
+	annot.SetContents(aJson.Contents)
+	annot.SetFlags(aJson.Flags)
+
+	return &annot
+}
+
+func popplerAnnotsMatch(a *poppler.Annot, b *poppler.Annot) bool {
+	aRect := a.Rect()
+	bRect := b.Rect()
+
+	aQuads := a.Quads()
+	bQuads := b.Quads()
+
+	if aRect.X1 != bRect.X1 ||
+		aRect.Y1 != bRect.Y1 ||
+		aRect.X2 != bRect.X2 ||
+		aRect.Y2 != bRect.Y2 {
+		return false
+	}
+
+	if len(aQuads) != len(bQuads) {
+		return false
+	}
+
+	for i := range aQuads {
+		q1 := aQuads[i]
+		q2 := bQuads[i]
+
+		if q1.P1.X != q2.P1.X || q1.P1.Y != q2.P1.Y ||
+			q1.P2.X != q2.P2.X || q1.P2.Y != q2.P2.Y ||
+			q1.P3.X != q2.P3.X || q1.P3.Y != q2.P3.Y ||
+			q1.P4.X != q2.P4.X || q1.P4.Y != q2.P4.Y {
+			return false
+		}
+	}
+
+	return true
+}
diff --git a/document/document.go b/document/document.go
new file mode 100644
index 0000000..a036eee
--- /dev/null
+++ b/document/document.go
@@ -0,0 +1,236 @@
+package document
+
+import (
+	"github.com/scrotadamus/ghligh/go-poppler"
+
+	"os"
+	"sync"
+
+	"strings"
+
+	"fmt"
+)
+
+const ghlighFilter = "ghligh-Y2lhbm5v:"
+
+// This is different from poppler's annot_mapping
+// it is the list of annotations mapped to the page index
+type AnnotsMap map[int][]AnnotJSON
+
+type GhlighDoc struct {
+	doc *poppler.Document
+	mu  sync.Mutex
+
+	Path         string    `json:"file"`
+	HashBuffer   string    `json:"hash"`
+	AnnotsBuffer AnnotsMap `json:"highlights,omitempty"`
+}
+
+type HighlightedText struct {
+	Page     int    `json:"page"`
+	Text     string `json:"text"`
+	Contents string `json:"contents,omitempty"`
+}
+
+func Open(filename string) (*GhlighDoc, error) {
+	var err error
+
+	g := &GhlighDoc{}
+
+	g.doc, err = poppler.Open(filename)
+	if err != nil {
+		fmt.Errorf("%s: error opening pdf %v", os.Args[0], err)
+		return nil, err
+	}
+	g.Path = filename
+	// HashDoc??
+
+	return g, nil
+}
+
+func (d *GhlighDoc) Close() {
+	d.AnnotsBuffer = nil
+	d.HashBuffer = ""
+	if d.doc != nil {
+		d.doc.Close()
+	}
+}
+
+func (d *GhlighDoc) Info() poppler.DocumentInfo {
+	return d.doc.Info()
+}
+
+func (d *GhlighDoc) tagExists(text string) bool {
+	for _, tag := range d.GetTags() {
+		if tag == text {
+			return true
+		}
+	}
+	return false
+}
+
+func (d *GhlighDoc) Tag(text string) {
+	if !d.tagExists(text) {
+		d.doc.Tag(ghlighFilter + text)
+	} else {
+		fmt.Fprintf(os.Stderr, "warning: tag %s already exist inside %s, i don't do anything\n", text, d.Path)
+	}
+}
+
+func (d *GhlighDoc) GetTags() []string {
+	var tags []string
+	annots := d.doc.GetTags(ghlighFilter)
+	for _, annot := range annots {
+		contents := strings.TrimPrefix(annot.Contents(), ghlighFilter)
+		tags = append(tags, contents)
+	}
+	return tags
+}
+
+func (d *GhlighDoc) RemoveTags(tags []string) int {
+	zeroPage := d.doc.GetPage(0)
+	var removedTags int
+
+	annots := d.doc.GetTags(ghlighFilter)
+	for _, annot := range annots {
+		contents := strings.TrimPrefix(annot.Contents(), ghlighFilter)
+		for _, tag := range tags {
+			if tag == contents {
+				zeroPage.RemoveAnnot(*annot)
+				removedTags += 1
+				break
+			}
+		}
+	}
+	return removedTags
+}
+
+func (d *GhlighDoc) Import(annotsMap AnnotsMap) (int, error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	annots_count := 0
+
+	var err error
+	d.AnnotsBuffer = annotsMap
+
+	for key := range d.AnnotsBuffer {
+		page := d.doc.GetPage(key)
+		for _, annot := range d.AnnotsBuffer[key] {
+			a := d.jsonToAnnot(annot)
+			if !isInPage(a, page) {
+				annots_count += 1
+				page.AddAnnot(*a)
+			}
+
+		}
+		page.Close()
+	}
+
+	d.AnnotsBuffer = nil
+	return annots_count, err
+}
+
+func integrityCheck(tizio *GhlighDoc, caio *GhlighDoc) {
+
+}
+
+func (d *GhlighDoc) Save() (bool, error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	tempFile, err := os.CreateTemp("", ".ghligh_*.pdf")
+	if err != nil {
+		return false, err
+	}
+	defer os.Remove(tempFile.Name())
+
+	ok, err := d.doc.Save(tempFile.Name())
+	if !ok {
+		return false, err
+	}
+
+	/* integrity check */
+	newDoc, err := Open(tempFile.Name())
+	if err != nil {
+		return false, err
+	}
+
+	if newDoc.HashDoc() != d.HashDoc() {
+		return false, fmt.Errorf("After saving document %s to %s its hash doesn't correspond the the old one", d.Path, tempFile.Name())
+	}
+
+	err = os.Rename(tempFile.Name(), d.Path)
+	if err != nil {
+		return false, err
+	}
+
+	return true, nil
+}
+
+func (d *GhlighDoc) Cat() []HighlightedText {
+	var highlights []HighlightedText
+
+	n_pages := d.doc.GetNPages()
+	for i := 0; i < n_pages; i++ {
+		page := d.doc.GetPage(i)
+		annots := page.GetAnnots()
+		for _, annot := range annots {
+			if annot.Type() == poppler.AnnotHighlight {
+				annotText := page.AnnotText(*annot)
+
+				highlights = append(highlights, HighlightedText{Page: i, Text: annotText, Contents: annot.Contents()})
+			}
+		}
+
+		page.Close()
+	}
+	return highlights
+}
+
+func (d *GhlighDoc) HasHighlights() bool {
+	// check if is tagged with ls
+	if d.tagExists("ls") {
+		return true
+	}
+
+	// check if it has highlights
+	n_pages := d.doc.GetNPages()
+	for i := 0; i < n_pages; i++ {
+		page := d.doc.GetPage(i)
+		annots := page.GetAnnots()
+		for _, annot := range annots {
+			if annot.Type() == poppler.AnnotHighlight {
+				return true
+			}
+		}
+
+		page.Close()
+	}
+	return false
+}
+
+func (d *GhlighDoc) GetAnnotsBuffer() AnnotsMap {
+	annots_json_of_page := make(AnnotsMap)
+
+	n := d.doc.GetNPages()
+	var annots_json []AnnotJSON
+	for i := 0; i < n; i++ {
+		annots_json = nil
+		page := d.doc.GetPage(i)
+
+		annots := page.GetAnnots()
+		for _, annot := range annots {
+			if annot.Type() == poppler.AnnotHighlight {
+				annot_json := annotToJson(*annot)
+				annots_json = append(annots_json, annot_json)
+			}
+		}
+
+		page.Close()
+
+		if len(annots_json) > 0 {
+			annots_json_of_page[i] = annots_json
+		}
+	}
+
+	return annots_json_of_page
+}
diff --git a/document/hash.go b/document/hash.go
new file mode 100644
index 0000000..fe9520c
--- /dev/null
+++ b/document/hash.go
@@ -0,0 +1,104 @@
+package document
+
+import (
+	"fmt"
+	"os"
+
+	"unsafe"
+	"reflect"
+
+	"math"
+
+	"runtime"
+	"sync"
+
+	"crypto/hmac"
+	"crypto/sha256"
+
+	"github.com/scrotadamus/ghligh/go-poppler"
+)
+
+
+var ghlighKey = []byte("ghligh-pdf-doc")
+
+var bufPool = sync.Pool{
+	New: func() interface{} {
+		return make([]byte, 0, os.Getpagesize())
+	},
+}
+
+type pageResult struct {
+	index int
+	buf   []byte
+}
+
+
+func sqrtInt(n int) int{
+	return int(math.Sqrt(float64(n)))
+}
+
+func continueAt(i, n int) bool {
+	// Very unlikely to edit a pdf and add a page in the center
+	return i < sqrtInt(n)/2  || i > n - sqrtInt(n)/2
+}
+
+// generate identifier from document based on document text (use layout instead)
+func (d *GhlighDoc) HashDoc() string {
+	nPages := d.doc.GetNPages()
+
+	hmacHash := hmac.New(sha256.New, ghlighKey)
+	resultsCh := make(chan pageResult, nPages)
+
+	var wg sync.WaitGroup
+
+	maxWorkers := runtime.NumCPU() + 1
+	sem := make(chan struct{}, maxWorkers)
+
+
+	for i := 0; continueAt(i, nPages); i++ {
+		wg.Add(1)
+		sem <- struct{}{}
+		go func(i int) {
+			defer wg.Done()
+			defer func() { <-sem }()
+
+			page := d.doc.GetPage(i)
+			text := page.Text()
+			page.Close()
+
+			buf := bufPool.Get().([]byte)
+			buf = buf[:0]
+			buf = append(buf, []byte(text)...)
+
+			resultsCh <- pageResult{index: i, buf: buf}
+		}(i)
+	}
+
+	wg.Wait()
+	close(resultsCh)
+
+	results := make([][]byte, nPages)
+	for res := range resultsCh {
+		results[res.index] = res.buf
+	}
+
+	for i := 0; continueAt(i, nPages); i++ {
+		hmacHash.Write(results[i])
+		hmacHash.Write([]byte{byte(i)})
+		bufPool.Put(results[i])
+	}
+	hmacHash.Write([]byte{byte(nPages)})
+
+	return fmt.Sprintf("%x", hmacHash.Sum(nil))
+}
+
+func rectToBytes(r *poppler.Rectangle) []byte {
+	size := int(unsafe.Sizeof(*r))
+
+	var sliceHeader reflect.SliceHeader
+	sliceHeader.Data = uintptr(unsafe.Pointer(r))
+	sliceHeader.Len = size
+	sliceHeader.Cap = size
+
+	return *(*[]byte)(unsafe.Pointer(&sliceHeader))
+}
diff --git a/document/utils.go b/document/utils.go
new file mode 100644
index 0000000..c6593c4
--- /dev/null
+++ b/document/utils.go
@@ -0,0 +1,30 @@
+package document
+
+import (
+	"github.com/scrotadamus/ghligh/go-poppler"
+
+	"encoding/json"
+)
+
+func unmarshallHighlights(jsonData string) (AnnotsMap, error) {
+	var annotsMap AnnotsMap
+
+	err := json.Unmarshal([]byte(jsonData), &struct {
+		Highlights *AnnotsMap `json:"highlights"`
+	}{
+		Highlights: &annotsMap,
+	})
+
+	return annotsMap, err
+}
+
+func isInPage(a *poppler.Annot, p *poppler.Page) bool {
+	annots := p.GetAnnots()
+	for _, annot := range annots {
+		if popplerAnnotsMatch(a, annot) {
+			return true
+		}
+	}
+
+	return false
+}