src/ports/SkFontHost_linux.cpp - platform/external/skqp - Gitiles

 /* libs/graphics/ports/SkFontHost_android.cpp
  **
  ** Copyright 2006, The Android Open Source Project
  **
  ** Licensed under the Apache License, Version 2.0 (the "License");
  ** you may not use this file except in compliance with the License.
  ** You may obtain a copy of the License at
  **
  **     http://www.apache.org/licenses/LICENSE-2.0
  **
  ** Unless required by applicable law or agreed to in writing, software
  ** distributed under the License is distributed on an "AS IS" BASIS,
  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ** See the License for the specific language governing permissions and
  ** limitations under the License.
  */

 #include "SkFontHost.h"
 #include "SkDescriptor.h"
 #include "SkMMapStream.h"
 #include "SkOSFile.h"
 #include "SkPaint.h"
 #include "SkString.h"
 #include "SkStream.h"
 #include "SkThread.h"
 #include "SkTSearch.h"
 #include <stdio.h>

 #define FONT_CACHE_MEMORY_BUDGET    (1 * 1024 * 1024)

 #ifndef SK_FONT_FILE_PREFIX
     #define SK_FONT_FILE_PREFIX      "/usr/share/fonts/truetype/msttcorefonts/"
 #endif

 SkTypeface::Style find_name_and_attributes(SkStream* stream, SkString* name,
                                            bool* isFixedWidth);

 static void GetFullPathForSysFonts(SkString* full, const char name[])
 {
     full->append(SK_FONT_FILE_PREFIX);
     full->append(name);
 }

 ///////////////////////////////////////////////////////////////////////////////

 struct FamilyRec;

 /*  This guy holds a mapping of a name -> family, used for looking up fonts.
  Since it is stored in a stretchy array that doesn't preserve object
  semantics, we don't use constructor/destructors, but just have explicit
  helpers to manage our internal bookkeeping.
  */
 struct NameFamilyPair {
     const char* fName;      // we own this
     FamilyRec*  fFamily;    // we don't own this, we just reference it

     void construct(const char name[], FamilyRec* family)
     {
         fName = strdup(name);
         fFamily = family;   // we don't own this, so just record the referene
     }
     void destruct()
     {
         free((char*)fName);
         // we don't own family, so just ignore our reference
     }
 };

 // we use atomic_inc to grow this for each typeface we create
 static int32_t gUniqueFontID;

 // this is the mutex that protects these globals
 static SkMutex gFamilyMutex;
 static FamilyRec* gFamilyHead;
 static SkTDArray<NameFamilyPair> gNameList;

 struct FamilyRec {
     FamilyRec*  fNext;
     SkTypeface* fFaces[4];

     FamilyRec()
     {
         fNext = gFamilyHead;
         memset(fFaces, 0, sizeof(fFaces));
         gFamilyHead = this;
     }
 };

 static SkTypeface* find_best_face(const FamilyRec* family,
                                   SkTypeface::Style style) {
     SkTypeface* const* faces = family->fFaces;

     if (faces[style] != NULL) { // exact match
         return faces[style];
     }
     // look for a matching bold
     style = (SkTypeface::Style)(style ^ SkTypeface::kItalic);
     if (faces[style] != NULL) {
         return faces[style];
     }
     // look for the plain
     if (faces[SkTypeface::kNormal] != NULL) {
         return faces[SkTypeface::kNormal];
     }
     // look for anything
     for (int i = 0; i < 4; i++) {
         if (faces[i] != NULL) {
             return faces[i];
         }
     }
     // should never get here, since the faces list should not be empty
     SkASSERT(!"faces list is empty");
     return NULL;
 }

 static FamilyRec* find_family(const SkTypeface* member) {
     FamilyRec* curr = gFamilyHead;
     while (curr != NULL) {
         for (int i = 0; i < 4; i++) {
             if (curr->fFaces[i] == member) {
                 return curr;
             }
         }
         curr = curr->fNext;
     }
     return NULL;
 }

 static SkTypeface* find_from_uniqueID(uint32_t uniqueID) {
     FamilyRec* curr = gFamilyHead;
     while (curr != NULL) {
         for (int i = 0; i < 4; i++) {
             SkTypeface* face = curr->fFaces[i];
             if (face != NULL && face->uniqueID() == uniqueID) {
                 return face;
             }
         }
         curr = curr->fNext;
     }
     return false;
 }

 static bool valid_uniqueID(uint32_t uniqueID) {
     return find_from_uniqueID(uniqueID) != NULL;
 }

 /*  Remove reference to this face from its family. If the resulting family
  is empty (has no faces), return that family, otherwise return NULL
  */
 static FamilyRec* remove_from_family(const SkTypeface* face) {
     FamilyRec* family = find_family(face);
     SkASSERT(family->fFaces[face->style()] == face);
     family->fFaces[face->style()] = NULL;

     for (int i = 0; i < 4; i++) {
         if (family->fFaces[i] != NULL) {    // family is non-empty
             return NULL;
         }
     }
     return family;  // return the empty family
 }

 // maybe we should make FamilyRec be doubly-linked
 static void detach_and_delete_family(FamilyRec* family) {
     FamilyRec* curr = gFamilyHead;
     FamilyRec* prev = NULL;

     while (curr != NULL) {
         FamilyRec* next = curr->fNext;
         if (curr == family) {
             if (prev == NULL) {
                 gFamilyHead = next;
             } else {
                 prev->fNext = next;
             }
             SkDELETE(family);
             return;
         }
         prev = curr;
         curr = next;
     }
     SkASSERT(!"Yikes, couldn't find family in our list to remove/delete");
 }

 static FamilyRec* find_familyrec(const char name[]) {
     const NameFamilyPair* list = gNameList.begin();
     int index = SkStrLCSearch(&list[0].fName, gNameList.count(), name,
                               sizeof(list[0]));
     return index >= 0 ? list[index].fFamily : NULL;
 }

 static SkTypeface* find_typeface(const char name[], SkTypeface::Style style) {
     FamilyRec* rec = find_familyrec(name);
     return rec ? find_best_face(rec, style) : NULL;
 }

 static SkTypeface* find_typeface(const SkTypeface* familyMember,
                                  SkTypeface::Style style) {
     const FamilyRec* family = find_family(familyMember);
     return family ? find_best_face(family, style) : NULL;
 }

 static void add_name(const char name[], FamilyRec* family) {
     SkAutoAsciiToLC tolc(name);
     name = tolc.lc();

     NameFamilyPair* list = gNameList.begin();
     int             count = gNameList.count();

     int index = SkStrLCSearch(&list[0].fName, count, name, sizeof(list[0]));

     if (index < 0) {
         list = gNameList.insert(~index);
         list->construct(name, family);
     }
 }

 static void remove_from_names(FamilyRec* emptyFamily) {
 #ifdef SK_DEBUG
     for (int i = 0; i < 4; i++) {
         SkASSERT(emptyFamily->fFaces[i] == NULL);
     }
 #endif

     SkTDArray<NameFamilyPair>& list = gNameList;

     // must go backwards when removing
     for (int i = list.count() - 1; i >= 0; --i) {
         NameFamilyPair* pair = &list[i];
         if (pair->fFamily == emptyFamily) {
             pair->destruct();
             list.remove(i);
         }
     }
 }

 ///////////////////////////////////////////////////////////////////////////////

 class FamilyTypeface : public SkTypeface {
 public:
     FamilyTypeface(Style style, bool sysFont, FamilyRec* family, bool isFixedWidth)
     : SkTypeface(style, sk_atomic_inc(&gUniqueFontID) + 1, isFixedWidth) {
         fIsSysFont = sysFont;

         SkAutoMutexAcquire  ac(gFamilyMutex);

         if (NULL == family) {
             family = SkNEW(FamilyRec);
         }
         family->fFaces[style] = this;
         fFamilyRec = family;    // just record it so we can return it if asked
     }

     virtual ~FamilyTypeface() {
         SkAutoMutexAcquire  ac(gFamilyMutex);

         // remove us from our family. If the family is now empty, we return
         // that and then remove that family from the name list
         FamilyRec* family = remove_from_family(this);
         if (NULL != family) {
             remove_from_names(family);
             detach_and_delete_family(family);
         }
     }

     bool isSysFont() const { return fIsSysFont; }
     FamilyRec* getFamily() const { return fFamilyRec; }
     // openStream returns a SkStream that has been ref-ed
     virtual SkStream* openStream() = 0;
     virtual const char* getUniqueString() const = 0;

 private:
     FamilyRec*  fFamilyRec; // we don't own this, just point to it
     bool        fIsSysFont;

     typedef SkTypeface INHERITED;
 };

 ///////////////////////////////////////////////////////////////////////////////

 /* This subclass is just a place holder for when we have no fonts available.
     It exists so that our globals (e.g. gFamilyHead) that expect *something*
     will not be null.
  */
 class EmptyTypeface : public FamilyTypeface {
 public:
     EmptyTypeface() : INHERITED(SkTypeface::kNormal, true, NULL, false) {}

     // overrides
     virtual SkStream* openStream() { return NULL; }
     virtual const char* getUniqueString() const { return NULL; }

 private:
     typedef FamilyTypeface INHERITED;
 };

 class StreamTypeface : public FamilyTypeface {
 public:
     StreamTypeface(Style style, bool sysFont, FamilyRec* family,
                    SkStream* stream, bool isFixedWidth)
     : INHERITED(style, sysFont, family, isFixedWidth) {
         stream->ref();
         fStream = stream;
     }
     virtual ~StreamTypeface() {
         fStream->unref();
     }

     // overrides
     virtual SkStream* openStream()
     {
       // openStream returns a refed stream.
       fStream->ref();
       return fStream;
     }
     virtual const char* getUniqueString() const { return NULL; }

 private:
     SkStream* fStream;

     typedef FamilyTypeface INHERITED;
 };

 class FileTypeface : public FamilyTypeface {
 public:
     FileTypeface(Style style, bool sysFont, FamilyRec* family,
                  const char path[], bool isFixedWidth)
         : INHERITED(style, sysFont, family, isFixedWidth) {
         fPath.set(path);
     }

     // overrides
     virtual SkStream* openStream()
     {
         SkStream* stream = SkNEW_ARGS(SkMMAPStream, (fPath.c_str()));

         // check for failure
         if (stream->getLength() <= 0) {
             SkDELETE(stream);
             // maybe MMAP isn't supported. try FILE
             stream = SkNEW_ARGS(SkFILEStream, (fPath.c_str()));
             if (stream->getLength() <= 0) {
                 SkDELETE(stream);
                 stream = NULL;
             }
         }
         return stream;
     }

     virtual const char* getUniqueString() const {
         const char* str = strrchr(fPath.c_str(), '/');
         if (str) {
             str += 1;   // skip the '/'
         }
         return str;
     }

 private:
     SkString fPath;

     typedef FamilyTypeface INHERITED;
 };

 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////

 static bool get_name_and_style(const char path[], SkString* name,
                                SkTypeface::Style* style, bool* isFixedWidth) {
     SkMMAPStream stream(path);
     if (stream.getLength() > 0) {
         *style = find_name_and_attributes(&stream, name, isFixedWidth);
         return true;
     }
     else {
         SkFILEStream stream(path);
         if (stream.getLength() > 0) {
             *style = find_name_and_attributes(&stream, name, isFixedWidth);
             return true;
         }
     }

     SkDebugf("---- failed to open <%s> as a font\n", path);
     return false;
 }

 // these globals are assigned (once) by load_system_fonts()
 static SkTypeface* gFallBackTypeface;
 static FamilyRec* gDefaultFamily;
 static SkTypeface* gDefaultNormal;

 static void load_system_fonts() {
     // check if we've already be called
     if (NULL != gDefaultNormal) {
         printf("---- default font %p\n", gDefaultNormal);
         return;
     }

     SkOSFile::Iter  iter(SK_FONT_FILE_PREFIX, ".ttf");
     SkString        name;
     int             count = 0;

     while (iter.next(&name, false)) {
         SkString filename;
         GetFullPathForSysFonts(&filename, name.c_str());

         bool isFixedWidth;
         SkString realname;
         SkTypeface::Style style = SkTypeface::kNormal; // avoid uninitialized warning

         if (!get_name_and_style(filename.c_str(), &realname, &style, &isFixedWidth)) {
             SkDebugf("------ can't load <%s> as a font\n", filename.c_str());
             continue;
         }

 //        SkDebugf("font: <%s> %d <%s>\n", realname.c_str(), style, filename.c_str());

         FamilyRec* family = find_familyrec(realname.c_str());
         if (family && family->fFaces[style]) {
 //            SkDebugf("---- skipping duplicate typeface %s style %d\n",
 //                     realname.c_str(), style);
             continue;
         }

         // this constructor puts us into the global gFamilyHead llist
         FamilyTypeface* tf = SkNEW_ARGS(FileTypeface,
                                         (style,
                                          true,  // system-font (cannot delete)
                                          family, // what family to join
                                          filename.c_str(),
                                          isFixedWidth) // filename
                                         );

         if (NULL == family) {
             add_name(realname.c_str(), tf->getFamily());
         }
         count += 1;
     }

     if (0 == count) {
         SkNEW(EmptyTypeface);
     }

     // do this after all fonts are loaded. This is our default font, and it
     // acts as a sentinel so we only execute load_system_fonts() once
     static const char* gDefaultNames[] = {
         "Arial", "Verdana", "Times New Roman", NULL
     };
     const char** names = gDefaultNames;
     while (*names) {
         SkTypeface* tf = find_typeface(*names++, SkTypeface::kNormal);
         if (tf) {
             gDefaultNormal = tf;
             break;
         }
     }
     // check if we found *something*
     if (NULL == gDefaultNormal) {
         if (NULL == gFamilyHead) {
             sk_throw();
         }
         for (int i = 0; i < 4; i++) {
             if ((gDefaultNormal = gFamilyHead->fFaces[i]) != NULL) {
                 break;
             }
         }
     }
     if (NULL == gDefaultNormal) {
         sk_throw();
     }
     gFallBackTypeface = gDefaultNormal;
     gDefaultFamily = find_family(gDefaultNormal);

 //    SkDebugf("---- default %p head %p family %p\n", gDefaultNormal, gFamilyHead, gDefaultFamily);
 }

 ///////////////////////////////////////////////////////////////////////////////

 void SkFontHost::Serialize(const SkTypeface* face, SkWStream* stream) {
 #if 0
     const char* name = ((FamilyTypeface*)face)->getUniqueString();

     stream->write8((uint8_t)face->getStyle());

     if (NULL == name || 0 == *name) {
         stream->writePackedUInt(0);
         //        SkDebugf("--- fonthost serialize null\n");
     } else {
         uint32_t len = strlen(name);
         stream->writePackedUInt(len);
         stream->write(name, len);
         //      SkDebugf("--- fonthost serialize <%s> %d\n", name, face->getStyle());
     }
 #endif
     sk_throw();
 }

 SkTypeface* SkFontHost::Deserialize(SkStream* stream) {
 #if 0
     load_system_fonts();

     int style = stream->readU8();

     int len = stream->readPackedUInt();
     if (len > 0) {
         SkString str;
         str.resize(len);
         stream->read(str.writable_str(), len);

         const FontInitRec* rec = gSystemFonts;
         for (size_t i = 0; i < SK_ARRAY_COUNT(gSystemFonts); i++) {
             if (strcmp(rec[i].fFileName, str.c_str()) == 0) {
                 // backup until we hit the fNames
                 for (int j = i; j >= 0; --j) {
                     if (rec[j].fNames != NULL) {
                         return SkFontHost::CreateTypeface(NULL, rec[j].fNames[0], NULL, 0,
                                                           (SkTypeface::Style)style);
                     }
                 }
             }
         }
     }
     return SkFontHost::CreateTypeface(NULL, NULL, NULL, 0, (SkTypeface::Style)style);
 #endif
     sk_throw();
     return NULL;
 }

 ///////////////////////////////////////////////////////////////////////////////

 SkTypeface* SkFontHost::CreateTypeface(const SkTypeface* familyFace,
                                        const char familyName[],
                                        const void* data, size_t bytelength,
                                        SkTypeface::Style style) {
     load_system_fonts();

     SkAutoMutexAcquire  ac(gFamilyMutex);

     // clip to legal style bits
     style = (SkTypeface::Style)(style & SkTypeface::kBoldItalic);

     SkTypeface* tf = NULL;

     if (NULL != familyFace) {
         tf = find_typeface(familyFace, style);
     } else if (NULL != familyName) {
         //        SkDebugf("======= familyName <%s>\n", familyName);
         tf = find_typeface(familyName, style);
     }

     if (NULL == tf) {
         tf = find_best_face(gDefaultFamily, style);
     }

     SkSafeRef(tf);
     return tf;
 }

 bool SkFontHost::ValidFontID(uint32_t fontID) {
     SkAutoMutexAcquire  ac(gFamilyMutex);

     return valid_uniqueID(fontID);
 }

 SkStream* SkFontHost::OpenStream(uint32_t fontID) {
     FamilyTypeface* tf = (FamilyTypeface*)find_from_uniqueID(fontID);
     SkStream* stream = tf ? tf->openStream() : NULL;

     if (stream && stream->getLength() == 0) {
         stream->unref();
         stream = NULL;
     }
     return stream;
 }

 size_t SkFontHost::GetFileName(SkFontID fontID, char path[], size_t length,
                                int32_t* index) {
     SkDebugf("SkFontHost::GetFileName unimplemented\n");
     return 0;
 }

 uint32_t SkFontHost::NextLogicalFont(uint32_t fontID) {
     return 0;
 }

 ///////////////////////////////////////////////////////////////////////////////

 SkTypeface* SkFontHost::CreateTypefaceFromStream(SkStream* stream) {
     if (NULL == stream || stream->getLength() <= 0) {
         SkDELETE(stream);
         return NULL;
     }

     bool isFixedWidth;
     SkString name;
     SkTypeface::Style style = find_name_and_attributes(stream, &name, &isFixedWidth);

     return SkNEW_ARGS(StreamTypeface, (style, false, NULL, stream, isFixedWidth));
 }

 SkTypeface* SkFontHost::CreateTypefaceFromFile(const char path[]) {
     SkTypeface* face = NULL;
     SkFILEStream* stream = SkNEW_ARGS(SkFILEStream, (path));

     if (stream->isValid()) {
         face = CreateTypefaceFromStream(stream);
     }
     stream->unref();
     return face;
 }

 ///////////////////////////////////////////////////////////////////////////////

 size_t SkFontHost::ShouldPurgeFontCache(size_t sizeAllocatedSoFar) {
     if (sizeAllocatedSoFar > FONT_CACHE_MEMORY_BUDGET)
         return sizeAllocatedSoFar - FONT_CACHE_MEMORY_BUDGET;
     else
         return 0;   // nothing to do
 }
	/* libs/graphics/ports/SkFontHost_android.cpp
	**
	** Copyright 2006, The Android Open Source Project
	**
	** Licensed under the Apache License, Version 2.0 (the "License");
	** you may not use this file except in compliance with the License.
	** You may obtain a copy of the License at
	**
	** http://www.apache.org/licenses/LICENSE-2.0
	**
	** Unless required by applicable law or agreed to in writing, software
	** distributed under the License is distributed on an "AS IS" BASIS,
	** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	** See the License for the specific language governing permissions and
	** limitations under the License.
	*/

	#include "SkFontHost.h"
	#include "SkDescriptor.h"
	#include "SkMMapStream.h"
	#include "SkOSFile.h"
	#include "SkPaint.h"
	#include "SkString.h"
	#include "SkStream.h"
	#include "SkThread.h"
	#include "SkTSearch.h"
	#include <stdio.h>

	#define FONT_CACHE_MEMORY_BUDGET (1 * 1024 * 1024)

	#ifndef SK_FONT_FILE_PREFIX
	#define SK_FONT_FILE_PREFIX "/usr/share/fonts/truetype/msttcorefonts/"
	#endif

	SkTypeface::Style find_name_and_attributes(SkStream* stream, SkString* name,
	bool* isFixedWidth);

	static void GetFullPathForSysFonts(SkString* full, const char name[])
	{
	full->append(SK_FONT_FILE_PREFIX);
	full->append(name);
	}

	///////////////////////////////////////////////////////////////////////////////

	struct FamilyRec;

	/* This guy holds a mapping of a name -> family, used for looking up fonts.
	Since it is stored in a stretchy array that doesn't preserve object
	semantics, we don't use constructor/destructors, but just have explicit
	helpers to manage our internal bookkeeping.
	*/
	struct NameFamilyPair {
	const char* fName; // we own this
	FamilyRec* fFamily; // we don't own this, we just reference it

	void construct(const char name[], FamilyRec* family)
	{
	fName = strdup(name);
	fFamily = family; // we don't own this, so just record the referene
	}
	void destruct()
	{
	free((char*)fName);
	// we don't own family, so just ignore our reference
	}
	};

	// we use atomic_inc to grow this for each typeface we create
	static int32_t gUniqueFontID;

	// this is the mutex that protects these globals
	static SkMutex gFamilyMutex;
	static FamilyRec* gFamilyHead;
	static SkTDArray<NameFamilyPair> gNameList;

	struct FamilyRec {
	FamilyRec* fNext;
	SkTypeface* fFaces[4];

	FamilyRec()
	{
	fNext = gFamilyHead;
	memset(fFaces, 0, sizeof(fFaces));
	gFamilyHead = this;
	}
	};

	static SkTypeface* find_best_face(const FamilyRec* family,
	SkTypeface::Style style) {
	SkTypeface* const* faces = family->fFaces;

	if (faces[style] != NULL) { // exact match
	return faces[style];
	}
	// look for a matching bold
	style = (SkTypeface::Style)(style ^ SkTypeface::kItalic);
	if (faces[style] != NULL) {
	return faces[style];
	}
	// look for the plain
	if (faces[SkTypeface::kNormal] != NULL) {
	return faces[SkTypeface::kNormal];
	}
	// look for anything
	for (int i = 0; i < 4; i++) {
	if (faces[i] != NULL) {
	return faces[i];
	}
	}
	// should never get here, since the faces list should not be empty
	SkASSERT(!"faces list is empty");
	return NULL;
	}

	static FamilyRec* find_family(const SkTypeface* member) {
	FamilyRec* curr = gFamilyHead;
	while (curr != NULL) {
	for (int i = 0; i < 4; i++) {
	if (curr->fFaces[i] == member) {
	return curr;
	}
	}
	curr = curr->fNext;
	}
	return NULL;
	}

	static SkTypeface* find_from_uniqueID(uint32_t uniqueID) {
	FamilyRec* curr = gFamilyHead;
	while (curr != NULL) {
	for (int i = 0; i < 4; i++) {
	SkTypeface* face = curr->fFaces[i];
	if (face != NULL && face->uniqueID() == uniqueID) {
	return face;
	}
	}
	curr = curr->fNext;
	}
	return false;
	}

	static bool valid_uniqueID(uint32_t uniqueID) {
	return find_from_uniqueID(uniqueID) != NULL;
	}

	/* Remove reference to this face from its family. If the resulting family
	is empty (has no faces), return that family, otherwise return NULL
	*/
	static FamilyRec* remove_from_family(const SkTypeface* face) {
	FamilyRec* family = find_family(face);
	SkASSERT(family->fFaces[face->style()] == face);
	family->fFaces[face->style()] = NULL;

	for (int i = 0; i < 4; i++) {
	if (family->fFaces[i] != NULL) { // family is non-empty
	return NULL;
	}
	}
	return family; // return the empty family
	}

	// maybe we should make FamilyRec be doubly-linked
	static void detach_and_delete_family(FamilyRec* family) {
	FamilyRec* curr = gFamilyHead;
	FamilyRec* prev = NULL;

	while (curr != NULL) {
	FamilyRec* next = curr->fNext;
	if (curr == family) {
	if (prev == NULL) {
	gFamilyHead = next;
	} else {
	prev->fNext = next;
	}
	SkDELETE(family);
	return;
	}
	prev = curr;
	curr = next;
	}
	SkASSERT(!"Yikes, couldn't find family in our list to remove/delete");
	}

	static FamilyRec* find_familyrec(const char name[]) {
	const NameFamilyPair* list = gNameList.begin();
	int index = SkStrLCSearch(&list[0].fName, gNameList.count(), name,
	sizeof(list[0]));
	return index >= 0 ? list[index].fFamily : NULL;
	}

	static SkTypeface* find_typeface(const char name[], SkTypeface::Style style) {
	FamilyRec* rec = find_familyrec(name);
	return rec ? find_best_face(rec, style) : NULL;
	}

	static SkTypeface* find_typeface(const SkTypeface* familyMember,
	SkTypeface::Style style) {
	const FamilyRec* family = find_family(familyMember);
	return family ? find_best_face(family, style) : NULL;
	}

	static void add_name(const char name[], FamilyRec* family) {
	SkAutoAsciiToLC tolc(name);
	name = tolc.lc();

	NameFamilyPair* list = gNameList.begin();
	int count = gNameList.count();

	int index = SkStrLCSearch(&list[0].fName, count, name, sizeof(list[0]));

	if (index < 0) {
	list = gNameList.insert(~index);
	list->construct(name, family);
	}
	}

	static void remove_from_names(FamilyRec* emptyFamily) {
	#ifdef SK_DEBUG
	for (int i = 0; i < 4; i++) {
	SkASSERT(emptyFamily->fFaces[i] == NULL);
	}
	#endif

	SkTDArray<NameFamilyPair>& list = gNameList;

	// must go backwards when removing
	for (int i = list.count() - 1; i >= 0; --i) {
	NameFamilyPair* pair = &list[i];
	if (pair->fFamily == emptyFamily) {
	pair->destruct();
	list.remove(i);
	}
	}
	}

	///////////////////////////////////////////////////////////////////////////////

	class FamilyTypeface : public SkTypeface {
	public:
	FamilyTypeface(Style style, bool sysFont, FamilyRec* family, bool isFixedWidth)
	: SkTypeface(style, sk_atomic_inc(&gUniqueFontID) + 1, isFixedWidth) {
	fIsSysFont = sysFont;

	SkAutoMutexAcquire ac(gFamilyMutex);

	if (NULL == family) {
	family = SkNEW(FamilyRec);
	}
	family->fFaces[style] = this;
	fFamilyRec = family; // just record it so we can return it if asked
	}

	virtual ~FamilyTypeface() {
	SkAutoMutexAcquire ac(gFamilyMutex);

	// remove us from our family. If the family is now empty, we return
	// that and then remove that family from the name list
	FamilyRec* family = remove_from_family(this);
	if (NULL != family) {
	remove_from_names(family);
	detach_and_delete_family(family);
	}
	}

	bool isSysFont() const { return fIsSysFont; }
	FamilyRec* getFamily() const { return fFamilyRec; }
	// openStream returns a SkStream that has been ref-ed
	virtual SkStream* openStream() = 0;
	virtual const char* getUniqueString() const = 0;

	private:
	FamilyRec* fFamilyRec; // we don't own this, just point to it
	bool fIsSysFont;

	typedef SkTypeface INHERITED;
	};

	///////////////////////////////////////////////////////////////////////////////

	/* This subclass is just a place holder for when we have no fonts available.
	It exists so that our globals (e.g. gFamilyHead) that expect something
	will not be null.
	*/
	class EmptyTypeface : public FamilyTypeface {
	public:
	EmptyTypeface() : INHERITED(SkTypeface::kNormal, true, NULL, false) {}

	// overrides
	virtual SkStream* openStream() { return NULL; }
	virtual const char* getUniqueString() const { return NULL; }

	private:
	typedef FamilyTypeface INHERITED;
	};

	class StreamTypeface : public FamilyTypeface {
	public:
	StreamTypeface(Style style, bool sysFont, FamilyRec* family,
	SkStream* stream, bool isFixedWidth)
	: INHERITED(style, sysFont, family, isFixedWidth) {
	stream->ref();
	fStream = stream;
	}
	virtual ~StreamTypeface() {
	fStream->unref();
	}

	// overrides
	virtual SkStream* openStream()
	{
	// openStream returns a refed stream.
	fStream->ref();
	return fStream;
	}
	virtual const char* getUniqueString() const { return NULL; }

	private:
	SkStream* fStream;

	typedef FamilyTypeface INHERITED;
	};

	class FileTypeface : public FamilyTypeface {
	public:
	FileTypeface(Style style, bool sysFont, FamilyRec* family,
	const char path[], bool isFixedWidth)
	: INHERITED(style, sysFont, family, isFixedWidth) {
	fPath.set(path);
	}

	// overrides
	virtual SkStream* openStream()
	{
	SkStream* stream = SkNEW_ARGS(SkMMAPStream, (fPath.c_str()));

	// check for failure
	if (stream->getLength() <= 0) {
	SkDELETE(stream);
	// maybe MMAP isn't supported. try FILE
	stream = SkNEW_ARGS(SkFILEStream, (fPath.c_str()));
	if (stream->getLength() <= 0) {
	SkDELETE(stream);
	stream = NULL;
	}
	}
	return stream;
	}

	virtual const char* getUniqueString() const {
	const char* str = strrchr(fPath.c_str(), '/');
	if (str) {
	str += 1; // skip the '/'
	}
	return str;
	}

	private:
	SkString fPath;

	typedef FamilyTypeface INHERITED;
	};

	///////////////////////////////////////////////////////////////////////////////
	///////////////////////////////////////////////////////////////////////////////

	static bool get_name_and_style(const char path[], SkString* name,
	SkTypeface::Style* style, bool* isFixedWidth) {
	SkMMAPStream stream(path);
	if (stream.getLength() > 0) {
	*style = find_name_and_attributes(&stream, name, isFixedWidth);
	return true;
	}
	else {
	SkFILEStream stream(path);
	if (stream.getLength() > 0) {
	*style = find_name_and_attributes(&stream, name, isFixedWidth);
	return true;
	}
	}

	SkDebugf("---- failed to open <%s> as a font\n", path);
	return false;
	}

	// these globals are assigned (once) by load_system_fonts()
	static SkTypeface* gFallBackTypeface;
	static FamilyRec* gDefaultFamily;
	static SkTypeface* gDefaultNormal;

	static void load_system_fonts() {
	// check if we've already be called
	if (NULL != gDefaultNormal) {
	printf("---- default font %p\n", gDefaultNormal);
	return;
	}

	SkOSFile::Iter iter(SK_FONT_FILE_PREFIX, ".ttf");
	SkString name;
	int count = 0;

	while (iter.next(&name, false)) {
	SkString filename;
	GetFullPathForSysFonts(&filename, name.c_str());

	bool isFixedWidth;
	SkString realname;
	SkTypeface::Style style = SkTypeface::kNormal; // avoid uninitialized warning

	if (!get_name_and_style(filename.c_str(), &realname, &style, &isFixedWidth)) {
	SkDebugf("------ can't load <%s> as a font\n", filename.c_str());
	continue;
	}

	// SkDebugf("font: <%s> %d <%s>\n", realname.c_str(), style, filename.c_str());

	FamilyRec* family = find_familyrec(realname.c_str());
	if (family && family->fFaces[style]) {
	// SkDebugf("---- skipping duplicate typeface %s style %d\n",
	// realname.c_str(), style);
	continue;
	}

	// this constructor puts us into the global gFamilyHead llist
	FamilyTypeface* tf = SkNEW_ARGS(FileTypeface,
	(style,
	true, // system-font (cannot delete)
	family, // what family to join
	filename.c_str(),
	isFixedWidth) // filename
	);

	if (NULL == family) {
	add_name(realname.c_str(), tf->getFamily());
	}
	count += 1;
	}

	if (0 == count) {
	SkNEW(EmptyTypeface);
	}

	// do this after all fonts are loaded. This is our default font, and it
	// acts as a sentinel so we only execute load_system_fonts() once
	static const char* gDefaultNames[] = {
	"Arial", "Verdana", "Times New Roman", NULL
	};
	const char** names = gDefaultNames;
	while (*names) {
	SkTypeface* tf = find_typeface(*names++, SkTypeface::kNormal);
	if (tf) {
	gDefaultNormal = tf;
	break;
	}
	}
	// check if we found something
	if (NULL == gDefaultNormal) {
	if (NULL == gFamilyHead) {
	sk_throw();
	}
	for (int i = 0; i < 4; i++) {
	if ((gDefaultNormal = gFamilyHead->fFaces[i]) != NULL) {
	break;
	}
	}
	}
	if (NULL == gDefaultNormal) {
	sk_throw();
	}
	gFallBackTypeface = gDefaultNormal;
	gDefaultFamily = find_family(gDefaultNormal);

	// SkDebugf("---- default %p head %p family %p\n", gDefaultNormal, gFamilyHead, gDefaultFamily);
	}

	///////////////////////////////////////////////////////////////////////////////

	void SkFontHost::Serialize(const SkTypeface* face, SkWStream* stream) {
	#if 0
	const char* name = ((FamilyTypeface*)face)->getUniqueString();

	stream->write8((uint8_t)face->getStyle());

	if (NULL == name \|\| 0 == *name) {
	stream->writePackedUInt(0);
	// SkDebugf("--- fonthost serialize null\n");
	} else {
	uint32_t len = strlen(name);
	stream->writePackedUInt(len);
	stream->write(name, len);
	// SkDebugf("--- fonthost serialize <%s> %d\n", name, face->getStyle());
	}
	#endif
	sk_throw();
	}

	SkTypeface* SkFontHost::Deserialize(SkStream* stream) {
	#if 0
	load_system_fonts();

	int style = stream->readU8();

	int len = stream->readPackedUInt();
	if (len > 0) {
	SkString str;
	str.resize(len);
	stream->read(str.writable_str(), len);

	const FontInitRec* rec = gSystemFonts;
	for (size_t i = 0; i < SK_ARRAY_COUNT(gSystemFonts); i++) {
	if (strcmp(rec[i].fFileName, str.c_str()) == 0) {
	// backup until we hit the fNames
	for (int j = i; j >= 0; --j) {
	if (rec[j].fNames != NULL) {
	return SkFontHost::CreateTypeface(NULL, rec[j].fNames[0], NULL, 0,
	(SkTypeface::Style)style);
	}
	}
	}
	}
	}
	return SkFontHost::CreateTypeface(NULL, NULL, NULL, 0, (SkTypeface::Style)style);
	#endif
	sk_throw();
	return NULL;
	}

	///////////////////////////////////////////////////////////////////////////////

	SkTypeface* SkFontHost::CreateTypeface(const SkTypeface* familyFace,
	const char familyName[],
	const void* data, size_t bytelength,
	SkTypeface::Style style) {
	load_system_fonts();

	SkAutoMutexAcquire ac(gFamilyMutex);

	// clip to legal style bits
	style = (SkTypeface::Style)(style & SkTypeface::kBoldItalic);

	SkTypeface* tf = NULL;

	if (NULL != familyFace) {
	tf = find_typeface(familyFace, style);
	} else if (NULL != familyName) {
	// SkDebugf("======= familyName <%s>\n", familyName);
	tf = find_typeface(familyName, style);
	}

	if (NULL == tf) {
	tf = find_best_face(gDefaultFamily, style);
	}

	SkSafeRef(tf);
	return tf;
	}

	bool SkFontHost::ValidFontID(uint32_t fontID) {
	SkAutoMutexAcquire ac(gFamilyMutex);

	return valid_uniqueID(fontID);
	}

	SkStream* SkFontHost::OpenStream(uint32_t fontID) {
	FamilyTypeface* tf = (FamilyTypeface*)find_from_uniqueID(fontID);
	SkStream* stream = tf ? tf->openStream() : NULL;

	if (stream && stream->getLength() == 0) {
	stream->unref();
	stream = NULL;
	}
	return stream;
	}

	size_t SkFontHost::GetFileName(SkFontID fontID, char path[], size_t length,
	int32_t* index) {
	SkDebugf("SkFontHost::GetFileName unimplemented\n");
	return 0;
	}

	uint32_t SkFontHost::NextLogicalFont(uint32_t fontID) {
	return 0;
	}

	///////////////////////////////////////////////////////////////////////////////

	SkTypeface* SkFontHost::CreateTypefaceFromStream(SkStream* stream) {
	if (NULL == stream \|\| stream->getLength() <= 0) {
	SkDELETE(stream);
	return NULL;
	}

	bool isFixedWidth;
	SkString name;
	SkTypeface::Style style = find_name_and_attributes(stream, &name, &isFixedWidth);

	return SkNEW_ARGS(StreamTypeface, (style, false, NULL, stream, isFixedWidth));
	}

	SkTypeface* SkFontHost::CreateTypefaceFromFile(const char path[]) {
	SkTypeface* face = NULL;
	SkFILEStream* stream = SkNEW_ARGS(SkFILEStream, (path));

	if (stream->isValid()) {
	face = CreateTypefaceFromStream(stream);
	}
	stream->unref();
	return face;
	}

	///////////////////////////////////////////////////////////////////////////////

	size_t SkFontHost::ShouldPurgeFontCache(size_t sizeAllocatedSoFar) {
	if (sizeAllocatedSoFar > FONT_CACHE_MEMORY_BUDGET)
	return sizeAllocatedSoFar - FONT_CACHE_MEMORY_BUDGET;
	else
	return 0; // nothing to do
	}